Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

24 files changed, 9052 insertions, 0 deletions

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
new file mode 100644
index 000000000..9754d8b31
--- /dev/null
+++ b/drivers/devfreq/Kconfig
@@ -0,0 +1,156 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig PM_DEVFREQ
+	bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
+	select SRCU
+	select PM_OPP
+	help
+	  A device may have a list of frequencies and voltages available.
+	  devfreq, a generic DVFS framework can be registered for a device
+	  in order to let the governor provided to devfreq choose an
+	  operating frequency based on the device driver's policy.
+
+	  Each device may have its own governor and policy. Devfreq can
+	  reevaluate the device state periodically and/or based on the
+	  notification to "nb", a notifier block, of devfreq.
+
+	  Like some CPUs with CPUfreq, a device may have multiple clocks.
+	  However, because the clock frequencies of a single device are
+	  determined by the single device's state, an instance of devfreq
+	  is attached to a single device and returns a "representative"
+	  clock frequency of the device, which is also attached
+	  to a device by 1-to-1. The device registering devfreq takes the
+	  responsibility to "interpret" the representative frequency and
+	  to set its every clock accordingly with the "target" callback
+	  given to devfreq.
+
+	  When OPP is used with the devfreq device, it is recommended to
+	  register devfreq's nb to the OPP's notifier head.  If OPP is
+	  used with the devfreq device, you may use OPP helper
+	  functions defined in devfreq.h.
+
+if PM_DEVFREQ
+
+comment "DEVFREQ Governors"
+
+config DEVFREQ_GOV_SIMPLE_ONDEMAND
+	tristate "Simple Ondemand"
+	help
+	  Chooses frequency based on the recent load on the device. Works
+	  similar as ONDEMAND governor of CPUFREQ does. A device with
+	  Simple-Ondemand should be able to provide busy/total counter
+	  values that imply the usage rate. A device may provide tuned
+	  values to the governor with data field at devfreq_add_device().
+
+config DEVFREQ_GOV_PERFORMANCE
+	tristate "Performance"
+	help
+	  Sets the frequency at the maximum available frequency.
+	  This governor always returns UINT_MAX as frequency so that
+	  the DEVFREQ framework returns the highest frequency available
+	  at any time.
+
+config DEVFREQ_GOV_POWERSAVE
+	tristate "Powersave"
+	help
+	  Sets the frequency at the minimum available frequency.
+	  This governor always returns 0 as frequency so that
+	  the DEVFREQ framework returns the lowest frequency available
+	  at any time.
+
+config DEVFREQ_GOV_USERSPACE
+	tristate "Userspace"
+	help
+	  Sets the frequency at the user specified one.
+	  This governor returns the user configured frequency if there
+	  has been an input to /sys/devices/.../userspace/set_freq.
+	  Otherwise, the governor does not change the frequency
+	  given at the initialization.
+
+config DEVFREQ_GOV_PASSIVE
+	tristate "Passive"
+	help
+	  Sets the frequency based on the frequency of its parent devfreq
+	  device. This governor does not change the frequency by itself
+	  through sysfs entries. The passive governor recommends that
+	  devfreq device uses the OPP table to get the frequency/voltage.
+
+comment "DEVFREQ Drivers"
+
+config ARM_EXYNOS_BUS_DEVFREQ
+	tristate "ARM Exynos Generic Memory Bus DEVFREQ Driver"
+	depends on ARCH_EXYNOS || COMPILE_TEST
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select DEVFREQ_GOV_PASSIVE
+	select DEVFREQ_EVENT_EXYNOS_PPMU
+	select PM_DEVFREQ_EVENT
+	help
+	  This adds the common DEVFREQ driver for Exynos Memory bus. Exynos
+	  Memory bus has one more group of memory bus (e.g, MIF and INT block).
+	  Each memory bus group could contain many memoby bus block. It reads
+	  PPMU counters of memory controllers by using DEVFREQ-event device
+	  and adjusts the operating frequencies and voltages with OPP support.
+	  This does not yet operate with optimal voltages.
+
+config ARM_IMX_BUS_DEVFREQ
+	tristate "i.MX Generic Bus DEVFREQ Driver"
+	depends on ARCH_MXC || COMPILE_TEST
+	select DEVFREQ_GOV_USERSPACE
+	help
+	  This adds the generic DEVFREQ driver for i.MX interconnects. It
+	  allows adjusting NIC/NOC frequency.
+
+config ARM_IMX8M_DDRC_DEVFREQ
+	tristate "i.MX8M DDRC DEVFREQ Driver"
+	depends on (ARCH_MXC && HAVE_ARM_SMCCC) || \
+		(COMPILE_TEST && HAVE_ARM_SMCCC)
+	select DEVFREQ_GOV_USERSPACE
+	help
+	  This adds the DEVFREQ driver for the i.MX8M DDR Controller. It allows
+	  adjusting DRAM frequency.
+
+config ARM_TEGRA_DEVFREQ
+	tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver"
+	depends on ARCH_TEGRA_3x_SOC || ARCH_TEGRA_114_SOC || \
+		ARCH_TEGRA_132_SOC || ARCH_TEGRA_124_SOC || \
+		ARCH_TEGRA_210_SOC || \
+		COMPILE_TEST
+	depends on COMMON_CLK
+	help
+	  This adds the DEVFREQ driver for the Tegra family of SoCs.
+	  It reads ACTMON counters of memory controllers and adjusts the
+	  operating frequencies and voltages with OPP support.
+
+config ARM_MEDIATEK_CCI_DEVFREQ
+	tristate "MEDIATEK CCI DEVFREQ Driver"
+	depends on ARM_MEDIATEK_CPUFREQ || COMPILE_TEST
+	select DEVFREQ_GOV_PASSIVE
+	help
+	  This adds a devfreq driver for MediaTek Cache Coherent Interconnect
+	  which is shared the same regulators with the cpu cluster. It can track
+	  buck voltages and update a proper CCI frequency. Use the notification
+	  to get the regulator status.
+
+config ARM_RK3399_DMC_DEVFREQ
+	tristate "ARM RK3399 DMC DEVFREQ Driver"
+	depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) || \
+		(COMPILE_TEST && HAVE_ARM_SMCCC)
+	select DEVFREQ_EVENT_ROCKCHIP_DFI
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select PM_DEVFREQ_EVENT
+	help
+	  This adds the DEVFREQ driver for the RK3399 DMC(Dynamic Memory Controller).
+	  It sets the frequency for the memory controller and reads the usage counts
+	  from hardware.
+
+config ARM_SUN8I_A33_MBUS_DEVFREQ
+	tristate "sun8i/sun50i MBUS DEVFREQ Driver"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	depends on COMMON_CLK
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	help
+	  This adds the DEVFREQ driver for the MBUS controller in some
+	  Allwinner sun8i (A33 through H3) and sun50i (A64 and H5) SoCs.
+
+source "drivers/devfreq/event/Kconfig"
+
+endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
new file mode 100644
index 000000000..bf40d0492
--- /dev/null
+++ b/drivers/devfreq/Makefile
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PM_DEVFREQ)	+= devfreq.o
+obj-$(CONFIG_PM_DEVFREQ_EVENT)	+= devfreq-event.o
+obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)	+= governor_simpleondemand.o
+obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
+obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
+obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
+obj-$(CONFIG_DEVFREQ_GOV_PASSIVE)	+= governor_passive.o
+
+# DEVFREQ Drivers
+obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ)	+= exynos-bus.o
+obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ)	+= imx-bus.o
+obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ)	+= imx8m-ddrc.o
+obj-$(CONFIG_ARM_MEDIATEK_CCI_DEVFREQ)	+= mtk-cci-devfreq.o
+obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ)	+= rk3399_dmc.o
+obj-$(CONFIG_ARM_SUN8I_A33_MBUS_DEVFREQ)	+= sun8i-a33-mbus.o
+obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra30-devfreq.o
+
+# DEVFREQ Event Drivers
+obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/
diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
new file mode 100644
index 000000000..6765c0333
--- /dev/null
+++ b/drivers/devfreq/devfreq-event.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * devfreq-event: a framework to provide raw data and events of devfreq devices
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This driver is based on drivers/devfreq/devfreq.c.
+ */
+
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/of.h>
+
+static struct class *devfreq_event_class;
+
+/* The list of all devfreq event list */
+static LIST_HEAD(devfreq_event_list);
+static DEFINE_MUTEX(devfreq_event_list_lock);
+
+#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
+
+/**
+ * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
+ *				 the enable_count of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function increase the enable_count and enable the
+ * devfreq-event device. The devfreq-event device should be enabled before
+ * using it by devfreq device.
+ */
+int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->enable
+			&& edev->enable_count == 0) {
+		ret = edev->desc->ops->enable(edev);
+		if (ret < 0)
+			goto err;
+	}
+	edev->enable_count++;
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
+
+/**
+ * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
+ *				  the enable_count of the devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function decrease the enable_count and disable the
+ * devfreq-event device. After the devfreq-event device is disabled,
+ * devfreq device can't use the devfreq-event device for get/set/reset
+ * operations.
+ */
+int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->enable_count <= 0) {
+		dev_warn(&edev->dev, "unbalanced enable_count\n");
+		ret = -EIO;
+		goto err;
+	}
+
+	if (edev->desc->ops && edev->desc->ops->disable
+			&& edev->enable_count == 1) {
+		ret = edev->desc->ops->disable(edev);
+		if (ret < 0)
+			goto err;
+	}
+	edev->enable_count--;
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
+
+/**
+ * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
+ *				not.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function check whether devfreq-event dev is enabled or not.
+ * If return true, the devfreq-event dev is enabeld. If return false, the
+ * devfreq-event dev is disabled.
+ */
+bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
+{
+	bool enabled = false;
+
+	if (!edev || !edev->desc)
+		return enabled;
+
+	mutex_lock(&edev->lock);
+
+	if (edev->enable_count > 0)
+		enabled = true;
+
+	mutex_unlock(&edev->lock);
+
+	return enabled;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
+
+/**
+ * devfreq_event_set_event() - Set event to devfreq-event dev to start.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function set the event to the devfreq-event device to start
+ * for getting the event data which could be various event type.
+ */
+int devfreq_event_set_event(struct devfreq_event_dev *edev)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->set_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->set_event(edev);
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_set_event);
+
+/**
+ * devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
+ * @edev	: the devfreq-event device
+ * @edata	: the calculated data of devfreq-event device
+ *
+ * Note that this function get the calculated event data from devfreq-event dev
+ * after stoping the progress of whole sequence of devfreq-event dev.
+ */
+int devfreq_event_get_event(struct devfreq_event_dev *edev,
+			    struct devfreq_event_data *edata)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->get_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EINVAL;
+
+	edata->total_count = edata->load_count = 0;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->get_event(edev, edata);
+	if (ret < 0)
+		edata->total_count = edata->load_count = 0;
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_event);
+
+/**
+ * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function stop all operations of devfreq-event dev and reset
+ * the current event data to make the devfreq-event device into initial state.
+ */
+int devfreq_event_reset_event(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->reset)
+		ret = edev->desc->ops->reset(edev);
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
+
+/**
+ * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
+ *					 devicetree.
+ * @dev		: the pointer to the given device
+ * @phandle_name: name of property holding a phandle value
+ * @index	: the index into list of devfreq-event device
+ *
+ * Note that this function return the pointer of devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
+					const char *phandle_name, int index)
+{
+	struct device_node *node;
+	struct devfreq_event_dev *edev;
+
+	if (!dev->of_node || !phandle_name)
+		return ERR_PTR(-EINVAL);
+
+	node = of_parse_phandle(dev->of_node, phandle_name, index);
+	if (!node)
+		return ERR_PTR(-ENODEV);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_for_each_entry(edev, &devfreq_event_list, node) {
+		if (edev->dev.parent && edev->dev.parent->of_node == node)
+			goto out;
+	}
+
+	list_for_each_entry(edev, &devfreq_event_list, node) {
+		if (of_node_name_eq(node, edev->desc->name))
+			goto out;
+	}
+	edev = NULL;
+out:
+	mutex_unlock(&devfreq_event_list_lock);
+
+	if (!edev) {
+		of_node_put(node);
+		return ERR_PTR(-ENODEV);
+	}
+
+	of_node_put(node);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
+
+/**
+ * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
+ * @dev		: the pointer to the given device
+ * @phandle_name: name of property holding a phandle value
+ *
+ * Note that this function return the count of devfreq-event devices.
+ */
+int devfreq_event_get_edev_count(struct device *dev, const char *phandle_name)
+{
+	int count;
+
+	if (!dev->of_node || !phandle_name) {
+		dev_err(dev, "device does not have a device node entry\n");
+		return -EINVAL;
+	}
+
+	count = of_property_count_elems_of_size(dev->of_node, phandle_name,
+						sizeof(u32));
+	if (count < 0) {
+		dev_err(dev,
+			"failed to get the count of devfreq-event in %pOF node\n",
+			dev->of_node);
+		return count;
+	}
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
+
+static void devfreq_event_release_edev(struct device *dev)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	kfree(edev);
+}
+
+/**
+ * devfreq_event_add_edev() - Add new devfreq-event device.
+ * @dev		: the device owning the devfreq-event device being created
+ * @desc	: the devfreq-event device's descriptor which include essential
+ *		  data for devfreq-event device.
+ *
+ * Note that this function add new devfreq-event device to devfreq-event class
+ * list and register the device of the devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+						struct devfreq_event_desc *desc)
+{
+	struct devfreq_event_dev *edev;
+	static atomic_t event_no = ATOMIC_INIT(-1);
+	int ret;
+
+	if (!dev || !desc)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->name || !desc->ops)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->ops->set_event || !desc->ops->get_event)
+		return ERR_PTR(-EINVAL);
+
+	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
+	if (!edev)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&edev->lock);
+	edev->desc = desc;
+	edev->enable_count = 0;
+	edev->dev.parent = dev;
+	edev->dev.class = devfreq_event_class;
+	edev->dev.release = devfreq_event_release_edev;
+
+	dev_set_name(&edev->dev, "event%d", atomic_inc_return(&event_no));
+	ret = device_register(&edev->dev);
+	if (ret < 0) {
+		put_device(&edev->dev);
+		return ERR_PTR(ret);
+	}
+	dev_set_drvdata(&edev->dev, edev);
+
+	INIT_LIST_HEAD(&edev->node);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_add(&edev->node, &devfreq_event_list);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
+
+/**
+ * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function removes the registered devfreq-event device.
+ */
+int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
+{
+	if (!edev)
+		return -EINVAL;
+
+	WARN_ON(edev->enable_count);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_del(&edev->node);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	device_unregister(&edev->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
+
+static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
+{
+	struct devfreq_event_dev **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+static void devm_devfreq_event_release(struct device *dev, void *res)
+{
+	devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
+}
+
+/**
+ * devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
+ * @dev		: the device owning the devfreq-event device being created
+ * @desc	: the devfreq-event device's descriptor which include essential
+ *		  data for devfreq-event device.
+ *
+ * Note that this function manages automatically the memory of devfreq-event
+ * device using device resource management and simplify the free operation
+ * for memory of devfreq-event device.
+ */
+struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
+						struct devfreq_event_desc *desc)
+{
+	struct devfreq_event_dev **ptr, *edev;
+
+	ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr),
+				GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	edev = devfreq_event_add_edev(dev, desc);
+	if (IS_ERR(edev)) {
+		devres_free(ptr);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	*ptr = edev;
+	devres_add(dev, ptr);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
+
+/**
+ * devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
+ * @dev		: the device owning the devfreq-event device being created
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function manages automatically the memory of devfreq-event
+ * device using device resource management.
+ */
+void devm_devfreq_event_remove_edev(struct device *dev,
+				struct devfreq_event_dev *edev)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_event_release,
+			       devm_devfreq_event_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
+
+/*
+ * Device attributes for devfreq-event class.
+ */
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", edev->desc->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t enable_count_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n", edev->enable_count);
+}
+static DEVICE_ATTR_RO(enable_count);
+
+static struct attribute *devfreq_event_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_enable_count.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(devfreq_event);
+
+static int __init devfreq_event_init(void)
+{
+	devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
+	if (IS_ERR(devfreq_event_class)) {
+		pr_err("%s: couldn't create class\n", __FILE__);
+		return PTR_ERR(devfreq_event_class);
+	}
+
+	devfreq_event_class->dev_groups = devfreq_event_groups;
+
+	return 0;
+}
+subsys_initcall(devfreq_event_init);
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
new file mode 100644
index 000000000..2951a87cc
--- /dev/null
+++ b/drivers/devfreq/devfreq.c
@@ -0,0 +1,2275 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ *	    for Non-CPU Devices.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/sched.h>
+#include <linux/debugfs.h>
+#include <linux/devfreq_cooling.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/pm_opp.h>
+#include <linux/devfreq.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/hrtimer.h>
+#include <linux/of.h>
+#include <linux/pm_qos.h>
+#include <linux/units.h>
+#include "governor.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/devfreq.h>
+
+#define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
+#define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
+
+static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
+
+/*
+ * devfreq core provides delayed work based load monitoring helper
+ * functions. Governors can use these or can implement their own
+ * monitoring mechanism.
+ */
+static struct workqueue_struct *devfreq_wq;
+
+/* The list of all device-devfreq governors */
+static LIST_HEAD(devfreq_governor_list);
+/* The list of all device-devfreq */
+static LIST_HEAD(devfreq_list);
+static DEFINE_MUTEX(devfreq_list_lock);
+
+static const char timer_name[][DEVFREQ_NAME_LEN] = {
+	[DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
+	[DEVFREQ_TIMER_DELAYED] = { "delayed" },
+};
+
+/**
+ * find_device_devfreq() - find devfreq struct using device pointer
+ * @dev:	device pointer used to lookup device devfreq.
+ *
+ * Search the list of device devfreqs and return the matched device's
+ * devfreq info. devfreq_list_lock should be held by the caller.
+ */
+static struct devfreq *find_device_devfreq(struct device *dev)
+{
+	struct devfreq *tmp_devfreq;
+
+	lockdep_assert_held(&devfreq_list_lock);
+
+	if (IS_ERR_OR_NULL(dev)) {
+		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
+		if (tmp_devfreq->dev.parent == dev)
+			return tmp_devfreq;
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+
+static unsigned long find_available_min_freq(struct devfreq *devfreq)
+{
+	struct dev_pm_opp *opp;
+	unsigned long min_freq = 0;
+
+	opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
+	if (IS_ERR(opp))
+		min_freq = 0;
+	else
+		dev_pm_opp_put(opp);
+
+	return min_freq;
+}
+
+static unsigned long find_available_max_freq(struct devfreq *devfreq)
+{
+	struct dev_pm_opp *opp;
+	unsigned long max_freq = ULONG_MAX;
+
+	opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
+	if (IS_ERR(opp))
+		max_freq = 0;
+	else
+		dev_pm_opp_put(opp);
+
+	return max_freq;
+}
+
+/**
+ * devfreq_get_freq_range() - Get the current freq range
+ * @devfreq:	the devfreq instance
+ * @min_freq:	the min frequency
+ * @max_freq:	the max frequency
+ *
+ * This takes into consideration all constraints.
+ */
+void devfreq_get_freq_range(struct devfreq *devfreq,
+			    unsigned long *min_freq,
+			    unsigned long *max_freq)
+{
+	unsigned long *freq_table = devfreq->freq_table;
+	s32 qos_min_freq, qos_max_freq;
+
+	lockdep_assert_held(&devfreq->lock);
+
+	/*
+	 * Initialize minimum/maximum frequency from freq table.
+	 * The devfreq drivers can initialize this in either ascending or
+	 * descending order and devfreq core supports both.
+	 */
+	if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
+		*min_freq = freq_table[0];
+		*max_freq = freq_table[devfreq->max_state - 1];
+	} else {
+		*min_freq = freq_table[devfreq->max_state - 1];
+		*max_freq = freq_table[0];
+	}
+
+	/* Apply constraints from PM QoS */
+	qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
+					     DEV_PM_QOS_MIN_FREQUENCY);
+	qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
+					     DEV_PM_QOS_MAX_FREQUENCY);
+	*min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
+	if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
+		*max_freq = min(*max_freq,
+				(unsigned long)HZ_PER_KHZ * qos_max_freq);
+
+	/* Apply constraints from OPP interface */
+	*min_freq = max(*min_freq, devfreq->scaling_min_freq);
+	*max_freq = min(*max_freq, devfreq->scaling_max_freq);
+
+	if (*min_freq > *max_freq)
+		*min_freq = *max_freq;
+}
+EXPORT_SYMBOL(devfreq_get_freq_range);
+
+/**
+ * devfreq_get_freq_level() - Lookup freq_table for the frequency
+ * @devfreq:	the devfreq instance
+ * @freq:	the target frequency
+ */
+static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
+{
+	int lev;
+
+	for (lev = 0; lev < devfreq->max_state; lev++)
+		if (freq == devfreq->freq_table[lev])
+			return lev;
+
+	return -EINVAL;
+}
+
+static int set_freq_table(struct devfreq *devfreq)
+{
+	struct dev_pm_opp *opp;
+	unsigned long freq;
+	int i, count;
+
+	/* Initialize the freq_table from OPP table */
+	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
+	if (count <= 0)
+		return -EINVAL;
+
+	devfreq->max_state = count;
+	devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
+					   devfreq->max_state,
+					   sizeof(*devfreq->freq_table),
+					   GFP_KERNEL);
+	if (!devfreq->freq_table)
+		return -ENOMEM;
+
+	for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
+		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
+		if (IS_ERR(opp)) {
+			devm_kfree(devfreq->dev.parent, devfreq->freq_table);
+			return PTR_ERR(opp);
+		}
+		dev_pm_opp_put(opp);
+		devfreq->freq_table[i] = freq;
+	}
+
+	return 0;
+}
+
+/**
+ * devfreq_update_status() - Update statistics of devfreq behavior
+ * @devfreq:	the devfreq instance
+ * @freq:	the update target frequency
+ */
+int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+{
+	int lev, prev_lev, ret = 0;
+	u64 cur_time;
+
+	lockdep_assert_held(&devfreq->lock);
+	cur_time = get_jiffies_64();
+
+	/* Immediately exit if previous_freq is not initialized yet. */
+	if (!devfreq->previous_freq)
+		goto out;
+
+	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
+	if (prev_lev < 0) {
+		ret = prev_lev;
+		goto out;
+	}
+
+	devfreq->stats.time_in_state[prev_lev] +=
+			cur_time - devfreq->stats.last_update;
+
+	lev = devfreq_get_freq_level(devfreq, freq);
+	if (lev < 0) {
+		ret = lev;
+		goto out;
+	}
+
+	if (lev != prev_lev) {
+		devfreq->stats.trans_table[
+			(prev_lev * devfreq->max_state) + lev]++;
+		devfreq->stats.total_trans++;
+	}
+
+out:
+	devfreq->stats.last_update = cur_time;
+	return ret;
+}
+EXPORT_SYMBOL(devfreq_update_status);
+
+/**
+ * find_devfreq_governor() - find devfreq governor from name
+ * @name:	name of the governor
+ *
+ * Search the list of devfreq governors and return the matched
+ * governor's pointer. devfreq_list_lock should be held by the caller.
+ */
+static struct devfreq_governor *find_devfreq_governor(const char *name)
+{
+	struct devfreq_governor *tmp_governor;
+
+	lockdep_assert_held(&devfreq_list_lock);
+
+	if (IS_ERR_OR_NULL(name)) {
+		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
+		if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
+			return tmp_governor;
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+
+/**
+ * try_then_request_governor() - Try to find the governor and request the
+ *                               module if is not found.
+ * @name:	name of the governor
+ *
+ * Search the list of devfreq governors and request the module and try again
+ * if is not found. This can happen when both drivers (the governor driver
+ * and the driver that call devfreq_add_device) are built as modules.
+ * devfreq_list_lock should be held by the caller. Returns the matched
+ * governor's pointer or an error pointer.
+ */
+static struct devfreq_governor *try_then_request_governor(const char *name)
+{
+	struct devfreq_governor *governor;
+	int err = 0;
+
+	lockdep_assert_held(&devfreq_list_lock);
+
+	if (IS_ERR_OR_NULL(name)) {
+		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	governor = find_devfreq_governor(name);
+	if (IS_ERR(governor)) {
+		mutex_unlock(&devfreq_list_lock);
+
+		if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
+			     DEVFREQ_NAME_LEN))
+			err = request_module("governor_%s", "simpleondemand");
+		else
+			err = request_module("governor_%s", name);
+		/* Restore previous state before return */
+		mutex_lock(&devfreq_list_lock);
+		if (err)
+			return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
+
+		governor = find_devfreq_governor(name);
+	}
+
+	return governor;
+}
+
+static int devfreq_notify_transition(struct devfreq *devfreq,
+		struct devfreq_freqs *freqs, unsigned int state)
+{
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (state) {
+	case DEVFREQ_PRECHANGE:
+		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+				DEVFREQ_PRECHANGE, freqs);
+		break;
+
+	case DEVFREQ_POSTCHANGE:
+		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+				DEVFREQ_POSTCHANGE, freqs);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
+			      u32 flags)
+{
+	struct devfreq_freqs freqs;
+	unsigned long cur_freq;
+	int err = 0;
+
+	if (devfreq->profile->get_cur_freq)
+		devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
+	else
+		cur_freq = devfreq->previous_freq;
+
+	freqs.old = cur_freq;
+	freqs.new = new_freq;
+	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
+
+	err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
+	if (err) {
+		freqs.new = cur_freq;
+		devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+		return err;
+	}
+
+	/*
+	 * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
+	 * and DEVFREQ_POSTCHANGE because for showing the correct frequency
+	 * change order of between devfreq device and passive devfreq device.
+	 */
+	if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
+		trace_devfreq_frequency(devfreq, new_freq, cur_freq);
+
+	freqs.new = new_freq;
+	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+
+	if (devfreq_update_status(devfreq, new_freq))
+		dev_warn(&devfreq->dev,
+			 "Couldn't update frequency transition information.\n");
+
+	devfreq->previous_freq = new_freq;
+
+	if (devfreq->suspend_freq)
+		devfreq->resume_freq = new_freq;
+
+	return err;
+}
+
+/**
+ * devfreq_update_target() - Reevaluate the device and configure frequency
+ *			   on the final stage.
+ * @devfreq:	the devfreq instance.
+ * @freq:	the new frequency of parent device. This argument
+ *		is only used for devfreq device using passive governor.
+ *
+ * Note: Lock devfreq->lock before calling devfreq_update_target. This function
+ *	 should be only used by both update_devfreq() and devfreq governors.
+ */
+int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
+{
+	unsigned long min_freq, max_freq;
+	int err = 0;
+	u32 flags = 0;
+
+	lockdep_assert_held(&devfreq->lock);
+
+	if (!devfreq->governor)
+		return -EINVAL;
+
+	/* Reevaluate the proper frequency */
+	err = devfreq->governor->get_target_freq(devfreq, &freq);
+	if (err)
+		return err;
+	devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+
+	if (freq < min_freq) {
+		freq = min_freq;
+		flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
+	}
+	if (freq > max_freq) {
+		freq = max_freq;
+		flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
+	}
+
+	return devfreq_set_target(devfreq, freq, flags);
+}
+EXPORT_SYMBOL(devfreq_update_target);
+
+/* Load monitoring helper functions for governors use */
+
+/**
+ * update_devfreq() - Reevaluate the device and configure frequency.
+ * @devfreq:	the devfreq instance.
+ *
+ * Note: Lock devfreq->lock before calling update_devfreq
+ *	 This function is exported for governors.
+ */
+int update_devfreq(struct devfreq *devfreq)
+{
+	return devfreq_update_target(devfreq, 0L);
+}
+EXPORT_SYMBOL(update_devfreq);
+
+/**
+ * devfreq_monitor() - Periodically poll devfreq objects.
+ * @work:	the work struct used to run devfreq_monitor periodically.
+ *
+ */
+static void devfreq_monitor(struct work_struct *work)
+{
+	int err;
+	struct devfreq *devfreq = container_of(work,
+					struct devfreq, work.work);
+
+	mutex_lock(&devfreq->lock);
+	err = update_devfreq(devfreq);
+	if (err)
+		dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
+
+	queue_delayed_work(devfreq_wq, &devfreq->work,
+				msecs_to_jiffies(devfreq->profile->polling_ms));
+	mutex_unlock(&devfreq->lock);
+
+	trace_devfreq_monitor(devfreq);
+}
+
+/**
+ * devfreq_monitor_start() - Start load monitoring of devfreq instance
+ * @devfreq:	the devfreq instance.
+ *
+ * Helper function for starting devfreq device load monitoring. By
+ * default delayed work based monitoring is supported. Function
+ * to be called from governor in response to DEVFREQ_GOV_START
+ * event when device is added to devfreq framework.
+ */
+void devfreq_monitor_start(struct devfreq *devfreq)
+{
+	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+		return;
+
+	switch (devfreq->profile->timer) {
+	case DEVFREQ_TIMER_DEFERRABLE:
+		INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
+		break;
+	case DEVFREQ_TIMER_DELAYED:
+		INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
+		break;
+	default:
+		return;
+	}
+
+	if (devfreq->profile->polling_ms)
+		queue_delayed_work(devfreq_wq, &devfreq->work,
+			msecs_to_jiffies(devfreq->profile->polling_ms));
+}
+EXPORT_SYMBOL(devfreq_monitor_start);
+
+/**
+ * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
+ * @devfreq:	the devfreq instance.
+ *
+ * Helper function to stop devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_STOP
+ * event when device is removed from devfreq framework.
+ */
+void devfreq_monitor_stop(struct devfreq *devfreq)
+{
+	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+		return;
+
+	cancel_delayed_work_sync(&devfreq->work);
+}
+EXPORT_SYMBOL(devfreq_monitor_stop);
+
+/**
+ * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
+ * @devfreq:	the devfreq instance.
+ *
+ * Helper function to suspend devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_SUSPEND
+ * event or when polling interval is set to zero.
+ *
+ * Note: Though this function is same as devfreq_monitor_stop(),
+ * intentionally kept separate to provide hooks for collecting
+ * transition statistics.
+ */
+void devfreq_monitor_suspend(struct devfreq *devfreq)
+{
+	mutex_lock(&devfreq->lock);
+	if (devfreq->stop_polling) {
+		mutex_unlock(&devfreq->lock);
+		return;
+	}
+
+	devfreq_update_status(devfreq, devfreq->previous_freq);
+	devfreq->stop_polling = true;
+	mutex_unlock(&devfreq->lock);
+
+	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+		return;
+
+	cancel_delayed_work_sync(&devfreq->work);
+}
+EXPORT_SYMBOL(devfreq_monitor_suspend);
+
+/**
+ * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
+ * @devfreq:    the devfreq instance.
+ *
+ * Helper function to resume devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_RESUME
+ * event or when polling interval is set to non-zero.
+ */
+void devfreq_monitor_resume(struct devfreq *devfreq)
+{
+	unsigned long freq;
+
+	mutex_lock(&devfreq->lock);
+
+	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+		goto out_update;
+
+	if (!devfreq->stop_polling)
+		goto out;
+
+	if (!delayed_work_pending(&devfreq->work) &&
+			devfreq->profile->polling_ms)
+		queue_delayed_work(devfreq_wq, &devfreq->work,
+			msecs_to_jiffies(devfreq->profile->polling_ms));
+
+out_update:
+	devfreq->stats.last_update = get_jiffies_64();
+	devfreq->stop_polling = false;
+
+	if (devfreq->profile->get_cur_freq &&
+		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
+		devfreq->previous_freq = freq;
+
+out:
+	mutex_unlock(&devfreq->lock);
+}
+EXPORT_SYMBOL(devfreq_monitor_resume);
+
+/**
+ * devfreq_update_interval() - Update device devfreq monitoring interval
+ * @devfreq:    the devfreq instance.
+ * @delay:      new polling interval to be set.
+ *
+ * Helper function to set new load monitoring polling interval. Function
+ * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
+ */
+void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
+{
+	unsigned int cur_delay = devfreq->profile->polling_ms;
+	unsigned int new_delay = *delay;
+
+	mutex_lock(&devfreq->lock);
+	devfreq->profile->polling_ms = new_delay;
+
+	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+		goto out;
+
+	if (devfreq->stop_polling)
+		goto out;
+
+	/* if new delay is zero, stop polling */
+	if (!new_delay) {
+		mutex_unlock(&devfreq->lock);
+		cancel_delayed_work_sync(&devfreq->work);
+		return;
+	}
+
+	/* if current delay is zero, start polling with new delay */
+	if (!cur_delay) {
+		queue_delayed_work(devfreq_wq, &devfreq->work,
+			msecs_to_jiffies(devfreq->profile->polling_ms));
+		goto out;
+	}
+
+	/* if current delay is greater than new delay, restart polling */
+	if (cur_delay > new_delay) {
+		mutex_unlock(&devfreq->lock);
+		cancel_delayed_work_sync(&devfreq->work);
+		mutex_lock(&devfreq->lock);
+		if (!devfreq->stop_polling)
+			queue_delayed_work(devfreq_wq, &devfreq->work,
+				msecs_to_jiffies(devfreq->profile->polling_ms));
+	}
+out:
+	mutex_unlock(&devfreq->lock);
+}
+EXPORT_SYMBOL(devfreq_update_interval);
+
+/**
+ * devfreq_notifier_call() - Notify that the device frequency requirements
+ *			     has been changed out of devfreq framework.
+ * @nb:		the notifier_block (supposed to be devfreq->nb)
+ * @type:	not used
+ * @devp:	not used
+ *
+ * Called by a notifier that uses devfreq->nb.
+ */
+static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
+				 void *devp)
+{
+	struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
+	int err = -EINVAL;
+
+	mutex_lock(&devfreq->lock);
+
+	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
+	if (!devfreq->scaling_min_freq)
+		goto out;
+
+	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
+	if (!devfreq->scaling_max_freq) {
+		devfreq->scaling_max_freq = ULONG_MAX;
+		goto out;
+	}
+
+	err = update_devfreq(devfreq);
+
+out:
+	mutex_unlock(&devfreq->lock);
+	if (err)
+		dev_err(devfreq->dev.parent,
+			"failed to update frequency from OPP notifier (%d)\n",
+			err);
+
+	return NOTIFY_OK;
+}
+
+/**
+ * qos_notifier_call() - Common handler for QoS constraints.
+ * @devfreq:    the devfreq instance.
+ */
+static int qos_notifier_call(struct devfreq *devfreq)
+{
+	int err;
+
+	mutex_lock(&devfreq->lock);
+	err = update_devfreq(devfreq);
+	mutex_unlock(&devfreq->lock);
+	if (err)
+		dev_err(devfreq->dev.parent,
+			"failed to update frequency from PM QoS (%d)\n",
+			err);
+
+	return NOTIFY_OK;
+}
+
+/**
+ * qos_min_notifier_call() - Callback for QoS min_freq changes.
+ * @nb:		Should be devfreq->nb_min
+ * @val:	not used
+ * @ptr:	not used
+ */
+static int qos_min_notifier_call(struct notifier_block *nb,
+					 unsigned long val, void *ptr)
+{
+	return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
+}
+
+/**
+ * qos_max_notifier_call() - Callback for QoS max_freq changes.
+ * @nb:		Should be devfreq->nb_max
+ * @val:	not used
+ * @ptr:	not used
+ */
+static int qos_max_notifier_call(struct notifier_block *nb,
+					 unsigned long val, void *ptr)
+{
+	return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
+}
+
+/**
+ * devfreq_dev_release() - Callback for struct device to release the device.
+ * @dev:	the devfreq device
+ *
+ * Remove devfreq from the list and release its resources.
+ */
+static void devfreq_dev_release(struct device *dev)
+{
+	struct devfreq *devfreq = to_devfreq(dev);
+	int err;
+
+	mutex_lock(&devfreq_list_lock);
+	list_del(&devfreq->node);
+	mutex_unlock(&devfreq_list_lock);
+
+	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
+					 DEV_PM_QOS_MAX_FREQUENCY);
+	if (err && err != -ENOENT)
+		dev_warn(dev->parent,
+			"Failed to remove max_freq notifier: %d\n", err);
+	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
+					 DEV_PM_QOS_MIN_FREQUENCY);
+	if (err && err != -ENOENT)
+		dev_warn(dev->parent,
+			"Failed to remove min_freq notifier: %d\n", err);
+
+	if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
+		err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
+		if (err < 0)
+			dev_warn(dev->parent,
+				"Failed to remove max_freq request: %d\n", err);
+	}
+	if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
+		err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
+		if (err < 0)
+			dev_warn(dev->parent,
+				"Failed to remove min_freq request: %d\n", err);
+	}
+
+	if (devfreq->profile->exit)
+		devfreq->profile->exit(devfreq->dev.parent);
+
+	if (devfreq->opp_table)
+		dev_pm_opp_put_opp_table(devfreq->opp_table);
+
+	mutex_destroy(&devfreq->lock);
+	srcu_cleanup_notifier_head(&devfreq->transition_notifier_list);
+	kfree(devfreq);
+}
+
+static void create_sysfs_files(struct devfreq *devfreq,
+				const struct devfreq_governor *gov);
+static void remove_sysfs_files(struct devfreq *devfreq,
+				const struct devfreq_governor *gov);
+
+/**
+ * devfreq_add_device() - Add devfreq feature to the device
+ * @dev:	the device to add devfreq feature.
+ * @profile:	device-specific profile to run devfreq.
+ * @governor_name:	name of the policy to choose frequency.
+ * @data:	devfreq driver pass to governors, governor should not change it.
+ */
+struct devfreq *devfreq_add_device(struct device *dev,
+				   struct devfreq_dev_profile *profile,
+				   const char *governor_name,
+				   void *data)
+{
+	struct devfreq *devfreq;
+	struct devfreq_governor *governor;
+	unsigned long min_freq, max_freq;
+	int err = 0;
+
+	if (!dev || !profile || !governor_name) {
+		dev_err(dev, "%s: Invalid parameters.\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	mutex_lock(&devfreq_list_lock);
+	devfreq = find_device_devfreq(dev);
+	mutex_unlock(&devfreq_list_lock);
+	if (!IS_ERR(devfreq)) {
+		dev_err(dev, "%s: devfreq device already exists!\n",
+			__func__);
+		err = -EINVAL;
+		goto err_out;
+	}
+
+	devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
+	if (!devfreq) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	mutex_init(&devfreq->lock);
+	mutex_lock(&devfreq->lock);
+	devfreq->dev.parent = dev;
+	devfreq->dev.class = devfreq_class;
+	devfreq->dev.release = devfreq_dev_release;
+	INIT_LIST_HEAD(&devfreq->node);
+	devfreq->profile = profile;
+	devfreq->previous_freq = profile->initial_freq;
+	devfreq->last_status.current_frequency = profile->initial_freq;
+	devfreq->data = data;
+	devfreq->nb.notifier_call = devfreq_notifier_call;
+
+	if (devfreq->profile->timer < 0
+		|| devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
+		mutex_unlock(&devfreq->lock);
+		err = -EINVAL;
+		goto err_dev;
+	}
+
+	if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
+		mutex_unlock(&devfreq->lock);
+		err = set_freq_table(devfreq);
+		if (err < 0)
+			goto err_dev;
+		mutex_lock(&devfreq->lock);
+	} else {
+		devfreq->freq_table = devfreq->profile->freq_table;
+		devfreq->max_state = devfreq->profile->max_state;
+	}
+
+	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
+	if (!devfreq->scaling_min_freq) {
+		mutex_unlock(&devfreq->lock);
+		err = -EINVAL;
+		goto err_dev;
+	}
+
+	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
+	if (!devfreq->scaling_max_freq) {
+		mutex_unlock(&devfreq->lock);
+		err = -EINVAL;
+		goto err_dev;
+	}
+
+	devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+
+	devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
+	devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
+	if (IS_ERR(devfreq->opp_table))
+		devfreq->opp_table = NULL;
+
+	atomic_set(&devfreq->suspend_count, 0);
+
+	dev_set_name(&devfreq->dev, "%s", dev_name(dev));
+	err = device_register(&devfreq->dev);
+	if (err) {
+		mutex_unlock(&devfreq->lock);
+		put_device(&devfreq->dev);
+		goto err_out;
+	}
+
+	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
+			array3_size(sizeof(unsigned int),
+				    devfreq->max_state,
+				    devfreq->max_state),
+			GFP_KERNEL);
+	if (!devfreq->stats.trans_table) {
+		mutex_unlock(&devfreq->lock);
+		err = -ENOMEM;
+		goto err_devfreq;
+	}
+
+	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
+			devfreq->max_state,
+			sizeof(*devfreq->stats.time_in_state),
+			GFP_KERNEL);
+	if (!devfreq->stats.time_in_state) {
+		mutex_unlock(&devfreq->lock);
+		err = -ENOMEM;
+		goto err_devfreq;
+	}
+
+	devfreq->stats.total_trans = 0;
+	devfreq->stats.last_update = get_jiffies_64();
+
+	srcu_init_notifier_head(&devfreq->transition_notifier_list);
+
+	mutex_unlock(&devfreq->lock);
+
+	err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
+				     DEV_PM_QOS_MIN_FREQUENCY, 0);
+	if (err < 0)
+		goto err_devfreq;
+	err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
+				     DEV_PM_QOS_MAX_FREQUENCY,
+				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
+	if (err < 0)
+		goto err_devfreq;
+
+	devfreq->nb_min.notifier_call = qos_min_notifier_call;
+	err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
+				      DEV_PM_QOS_MIN_FREQUENCY);
+	if (err)
+		goto err_devfreq;
+
+	devfreq->nb_max.notifier_call = qos_max_notifier_call;
+	err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
+				      DEV_PM_QOS_MAX_FREQUENCY);
+	if (err)
+		goto err_devfreq;
+
+	mutex_lock(&devfreq_list_lock);
+
+	governor = try_then_request_governor(governor_name);
+	if (IS_ERR(governor)) {
+		dev_err(dev, "%s: Unable to find governor for the device\n",
+			__func__);
+		err = PTR_ERR(governor);
+		goto err_init;
+	}
+
+	devfreq->governor = governor;
+	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
+						NULL);
+	if (err) {
+		dev_err_probe(dev, err,
+			"%s: Unable to start governor for the device\n",
+			 __func__);
+		goto err_init;
+	}
+	create_sysfs_files(devfreq, devfreq->governor);
+
+	list_add(&devfreq->node, &devfreq_list);
+
+	mutex_unlock(&devfreq_list_lock);
+
+	if (devfreq->profile->is_cooling_device) {
+		devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
+		if (IS_ERR(devfreq->cdev))
+			devfreq->cdev = NULL;
+	}
+
+	return devfreq;
+
+err_init:
+	mutex_unlock(&devfreq_list_lock);
+err_devfreq:
+	devfreq_remove_device(devfreq);
+	devfreq = NULL;
+err_dev:
+	kfree(devfreq);
+err_out:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(devfreq_add_device);
+
+/**
+ * devfreq_remove_device() - Remove devfreq feature from a device.
+ * @devfreq:	the devfreq instance to be removed
+ *
+ * The opposite of devfreq_add_device().
+ */
+int devfreq_remove_device(struct devfreq *devfreq)
+{
+	if (!devfreq)
+		return -EINVAL;
+
+	devfreq_cooling_unregister(devfreq->cdev);
+
+	if (devfreq->governor) {
+		devfreq->governor->event_handler(devfreq,
+						 DEVFREQ_GOV_STOP, NULL);
+		remove_sysfs_files(devfreq, devfreq->governor);
+	}
+
+	device_unregister(&devfreq->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(devfreq_remove_device);
+
+static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
+{
+	struct devfreq **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+static void devm_devfreq_dev_release(struct device *dev, void *res)
+{
+	devfreq_remove_device(*(struct devfreq **)res);
+}
+
+/**
+ * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
+ * @dev:	the device to add devfreq feature.
+ * @profile:	device-specific profile to run devfreq.
+ * @governor_name:	name of the policy to choose frequency.
+ * @data:	 devfreq driver pass to governors, governor should not change it.
+ *
+ * This function manages automatically the memory of devfreq device using device
+ * resource management and simplify the free operation for memory of devfreq
+ * device.
+ */
+struct devfreq *devm_devfreq_add_device(struct device *dev,
+					struct devfreq_dev_profile *profile,
+					const char *governor_name,
+					void *data)
+{
+	struct devfreq **ptr, *devfreq;
+
+	ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	devfreq = devfreq_add_device(dev, profile, governor_name, data);
+	if (IS_ERR(devfreq)) {
+		devres_free(ptr);
+		return devfreq;
+	}
+
+	*ptr = devfreq;
+	devres_add(dev, ptr);
+
+	return devfreq;
+}
+EXPORT_SYMBOL(devm_devfreq_add_device);
+
+#ifdef CONFIG_OF
+/*
+ * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
+ * @node - pointer to device_node
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+	struct devfreq *devfreq;
+
+	if (!node)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&devfreq_list_lock);
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		if (devfreq->dev.parent
+			&& devfreq->dev.parent->of_node == node) {
+			mutex_unlock(&devfreq_list_lock);
+			return devfreq;
+		}
+	}
+	mutex_unlock(&devfreq_list_lock);
+
+	return ERR_PTR(-ENODEV);
+}
+
+/*
+ * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
+ * @dev - instance to the given device
+ * @phandle_name - name of property holding a phandle value
+ * @index - index into list of devfreq
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+					const char *phandle_name, int index)
+{
+	struct device_node *node;
+	struct devfreq *devfreq;
+
+	if (!dev || !phandle_name)
+		return ERR_PTR(-EINVAL);
+
+	if (!dev->of_node)
+		return ERR_PTR(-EINVAL);
+
+	node = of_parse_phandle(dev->of_node, phandle_name, index);
+	if (!node)
+		return ERR_PTR(-ENODEV);
+
+	devfreq = devfreq_get_devfreq_by_node(node);
+	of_node_put(node);
+
+	return devfreq;
+}
+
+#else
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+					const char *phandle_name, int index)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif /* CONFIG_OF */
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
+
+/**
+ * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
+ * @dev:	the device from which to remove devfreq feature.
+ * @devfreq:	the devfreq instance to be removed
+ */
+void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_dev_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_remove_device);
+
+/**
+ * devfreq_suspend_device() - Suspend devfreq of a device.
+ * @devfreq: the devfreq instance to be suspended
+ *
+ * This function is intended to be called by the pm callbacks
+ * (e.g., runtime_suspend, suspend) of the device driver that
+ * holds the devfreq.
+ */
+int devfreq_suspend_device(struct devfreq *devfreq)
+{
+	int ret;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	if (atomic_inc_return(&devfreq->suspend_count) > 1)
+		return 0;
+
+	if (devfreq->governor) {
+		ret = devfreq->governor->event_handler(devfreq,
+					DEVFREQ_GOV_SUSPEND, NULL);
+		if (ret)
+			return ret;
+	}
+
+	if (devfreq->suspend_freq) {
+		mutex_lock(&devfreq->lock);
+		ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
+		mutex_unlock(&devfreq->lock);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(devfreq_suspend_device);
+
+/**
+ * devfreq_resume_device() - Resume devfreq of a device.
+ * @devfreq: the devfreq instance to be resumed
+ *
+ * This function is intended to be called by the pm callbacks
+ * (e.g., runtime_resume, resume) of the device driver that
+ * holds the devfreq.
+ */
+int devfreq_resume_device(struct devfreq *devfreq)
+{
+	int ret;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	if (atomic_dec_return(&devfreq->suspend_count) >= 1)
+		return 0;
+
+	if (devfreq->resume_freq) {
+		mutex_lock(&devfreq->lock);
+		ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
+		mutex_unlock(&devfreq->lock);
+		if (ret)
+			return ret;
+	}
+
+	if (devfreq->governor) {
+		ret = devfreq->governor->event_handler(devfreq,
+					DEVFREQ_GOV_RESUME, NULL);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(devfreq_resume_device);
+
+/**
+ * devfreq_suspend() - Suspend devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycles for suspending governors
+ * and devices preserving the state for resume. On some platforms the devfreq
+ * device must have precise state (frequency) after resume in order to provide
+ * fully operating setup.
+ */
+void devfreq_suspend(void)
+{
+	struct devfreq *devfreq;
+	int ret;
+
+	mutex_lock(&devfreq_list_lock);
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		ret = devfreq_suspend_device(devfreq);
+		if (ret)
+			dev_err(&devfreq->dev,
+				"failed to suspend devfreq device\n");
+	}
+	mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_resume() - Resume devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycle for resuming governors and
+ * devices that are suspended with devfreq_suspend().
+ */
+void devfreq_resume(void)
+{
+	struct devfreq *devfreq;
+	int ret;
+
+	mutex_lock(&devfreq_list_lock);
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		ret = devfreq_resume_device(devfreq);
+		if (ret)
+			dev_warn(&devfreq->dev,
+				 "failed to resume devfreq device\n");
+	}
+	mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_add_governor() - Add devfreq governor
+ * @governor:	the devfreq governor to be added
+ */
+int devfreq_add_governor(struct devfreq_governor *governor)
+{
+	struct devfreq_governor *g;
+	struct devfreq *devfreq;
+	int err = 0;
+
+	if (!governor) {
+		pr_err("%s: Invalid parameters.\n", __func__);
+		return -EINVAL;
+	}
+
+	mutex_lock(&devfreq_list_lock);
+	g = find_devfreq_governor(governor->name);
+	if (!IS_ERR(g)) {
+		pr_err("%s: governor %s already registered\n", __func__,
+		       g->name);
+		err = -EINVAL;
+		goto err_out;
+	}
+
+	list_add(&governor->node, &devfreq_governor_list);
+
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		int ret = 0;
+		struct device *dev = devfreq->dev.parent;
+
+		if (!strncmp(devfreq->governor->name, governor->name,
+			     DEVFREQ_NAME_LEN)) {
+			/* The following should never occur */
+			if (devfreq->governor) {
+				dev_warn(dev,
+					 "%s: Governor %s already present\n",
+					 __func__, devfreq->governor->name);
+				ret = devfreq->governor->event_handler(devfreq,
+							DEVFREQ_GOV_STOP, NULL);
+				if (ret) {
+					dev_warn(dev,
+						 "%s: Governor %s stop = %d\n",
+						 __func__,
+						 devfreq->governor->name, ret);
+				}
+				/* Fall through */
+			}
+			devfreq->governor = governor;
+			ret = devfreq->governor->event_handler(devfreq,
+						DEVFREQ_GOV_START, NULL);
+			if (ret) {
+				dev_warn(dev, "%s: Governor %s start=%d\n",
+					 __func__, devfreq->governor->name,
+					 ret);
+			}
+		}
+	}
+
+err_out:
+	mutex_unlock(&devfreq_list_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(devfreq_add_governor);
+
+static void devm_devfreq_remove_governor(void *governor)
+{
+	WARN_ON(devfreq_remove_governor(governor));
+}
+
+/**
+ * devm_devfreq_add_governor() - Add devfreq governor
+ * @dev:	device which adds devfreq governor
+ * @governor:	the devfreq governor to be added
+ *
+ * This is a resource-managed variant of devfreq_add_governor().
+ */
+int devm_devfreq_add_governor(struct device *dev,
+			      struct devfreq_governor *governor)
+{
+	int err;
+
+	err = devfreq_add_governor(governor);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
+					governor);
+}
+EXPORT_SYMBOL(devm_devfreq_add_governor);
+
+/**
+ * devfreq_remove_governor() - Remove devfreq feature from a device.
+ * @governor:	the devfreq governor to be removed
+ */
+int devfreq_remove_governor(struct devfreq_governor *governor)
+{
+	struct devfreq_governor *g;
+	struct devfreq *devfreq;
+	int err = 0;
+
+	if (!governor) {
+		pr_err("%s: Invalid parameters.\n", __func__);
+		return -EINVAL;
+	}
+
+	mutex_lock(&devfreq_list_lock);
+	g = find_devfreq_governor(governor->name);
+	if (IS_ERR(g)) {
+		pr_err("%s: governor %s not registered\n", __func__,
+		       governor->name);
+		err = PTR_ERR(g);
+		goto err_out;
+	}
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		int ret;
+		struct device *dev = devfreq->dev.parent;
+
+		if (!strncmp(devfreq->governor->name, governor->name,
+			     DEVFREQ_NAME_LEN)) {
+			/* we should have a devfreq governor! */
+			if (!devfreq->governor) {
+				dev_warn(dev, "%s: Governor %s NOT present\n",
+					 __func__, governor->name);
+				continue;
+				/* Fall through */
+			}
+			ret = devfreq->governor->event_handler(devfreq,
+						DEVFREQ_GOV_STOP, NULL);
+			if (ret) {
+				dev_warn(dev, "%s: Governor %s stop=%d\n",
+					 __func__, devfreq->governor->name,
+					 ret);
+			}
+			devfreq->governor = NULL;
+		}
+	}
+
+	list_del(&governor->node);
+err_out:
+	mutex_unlock(&devfreq_list_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(devfreq_remove_governor);
+
+static ssize_t name_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+	return sprintf(buf, "%s\n", dev_name(df->dev.parent));
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t governor_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+
+	if (!df->governor)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", df->governor->name);
+}
+
+static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	int ret;
+	char str_governor[DEVFREQ_NAME_LEN + 1];
+	const struct devfreq_governor *governor, *prev_governor;
+
+	if (!df->governor)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
+	if (ret != 1)
+		return -EINVAL;
+
+	mutex_lock(&devfreq_list_lock);
+	governor = try_then_request_governor(str_governor);
+	if (IS_ERR(governor)) {
+		ret = PTR_ERR(governor);
+		goto out;
+	}
+	if (df->governor == governor) {
+		ret = 0;
+		goto out;
+	} else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
+		|| IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Stop the current governor and remove the specific sysfs files
+	 * which depend on current governor.
+	 */
+	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
+	if (ret) {
+		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
+			 __func__, df->governor->name, ret);
+		goto out;
+	}
+	remove_sysfs_files(df, df->governor);
+
+	/*
+	 * Start the new governor and create the specific sysfs files
+	 * which depend on the new governor.
+	 */
+	prev_governor = df->governor;
+	df->governor = governor;
+	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+	if (ret) {
+		dev_warn(dev, "%s: Governor %s not started(%d)\n",
+			 __func__, df->governor->name, ret);
+
+		/* Restore previous governor */
+		df->governor = prev_governor;
+		ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+		if (ret) {
+			dev_err(dev,
+				"%s: reverting to Governor %s failed (%d)\n",
+				__func__, prev_governor->name, ret);
+			df->governor = NULL;
+			goto out;
+		}
+	}
+
+	/*
+	 * Create the sysfs files for the new governor. But if failed to start
+	 * the new governor, restore the sysfs files of previous governor.
+	 */
+	create_sysfs_files(df, df->governor);
+
+out:
+	mutex_unlock(&devfreq_list_lock);
+
+	if (!ret)
+		ret = count;
+	return ret;
+}
+static DEVICE_ATTR_RW(governor);
+
+static ssize_t available_governors_show(struct device *d,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct devfreq *df = to_devfreq(d);
+	ssize_t count = 0;
+
+	if (!df->governor)
+		return -EINVAL;
+
+	mutex_lock(&devfreq_list_lock);
+
+	/*
+	 * The devfreq with immutable governor (e.g., passive) shows
+	 * only own governor.
+	 */
+	if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
+		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
+				  "%s ", df->governor->name);
+	/*
+	 * The devfreq device shows the registered governor except for
+	 * immutable governors such as passive governor .
+	 */
+	} else {
+		struct devfreq_governor *governor;
+
+		list_for_each_entry(governor, &devfreq_governor_list, node) {
+			if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
+				continue;
+			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+					   "%s ", governor->name);
+		}
+	}
+
+	mutex_unlock(&devfreq_list_lock);
+
+	/* Truncate the trailing space */
+	if (count)
+		count--;
+
+	count += sprintf(&buf[count], "\n");
+
+	return count;
+}
+static DEVICE_ATTR_RO(available_governors);
+
+static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	unsigned long freq;
+	struct devfreq *df = to_devfreq(dev);
+
+	if (!df->profile)
+		return -EINVAL;
+
+	if (df->profile->get_cur_freq &&
+		!df->profile->get_cur_freq(df->dev.parent, &freq))
+		return sprintf(buf, "%lu\n", freq);
+
+	return sprintf(buf, "%lu\n", df->previous_freq);
+}
+static DEVICE_ATTR_RO(cur_freq);
+
+static ssize_t target_freq_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+
+	return sprintf(buf, "%lu\n", df->previous_freq);
+}
+static DEVICE_ATTR_RO(target_freq);
+
+static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned long value;
+	int ret;
+
+	/*
+	 * Protect against theoretical sysfs writes between
+	 * device_add and dev_pm_qos_add_request
+	 */
+	if (!dev_pm_qos_request_active(&df->user_min_freq_req))
+		return -EAGAIN;
+
+	ret = sscanf(buf, "%lu", &value);
+	if (ret != 1)
+		return -EINVAL;
+
+	/* Round down to kHz for PM QoS */
+	ret = dev_pm_qos_update_request(&df->user_min_freq_req,
+					value / HZ_PER_KHZ);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned long min_freq, max_freq;
+
+	mutex_lock(&df->lock);
+	devfreq_get_freq_range(df, &min_freq, &max_freq);
+	mutex_unlock(&df->lock);
+
+	return sprintf(buf, "%lu\n", min_freq);
+}
+static DEVICE_ATTR_RW(min_freq);
+
+static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned long value;
+	int ret;
+
+	/*
+	 * Protect against theoretical sysfs writes between
+	 * device_add and dev_pm_qos_add_request
+	 */
+	if (!dev_pm_qos_request_active(&df->user_max_freq_req))
+		return -EINVAL;
+
+	ret = sscanf(buf, "%lu", &value);
+	if (ret != 1)
+		return -EINVAL;
+
+	/*
+	 * PM QoS frequencies are in kHz so we need to convert. Convert by
+	 * rounding upwards so that the acceptable interval never shrinks.
+	 *
+	 * For example if the user writes "666666666" to sysfs this value will
+	 * be converted to 666667 kHz and back to 666667000 Hz before an OPP
+	 * lookup, this ensures that an OPP of 666666666Hz is still accepted.
+	 *
+	 * A value of zero means "no limit".
+	 */
+	if (value)
+		value = DIV_ROUND_UP(value, HZ_PER_KHZ);
+	else
+		value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
+
+	ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned long min_freq, max_freq;
+
+	mutex_lock(&df->lock);
+	devfreq_get_freq_range(df, &min_freq, &max_freq);
+	mutex_unlock(&df->lock);
+
+	return sprintf(buf, "%lu\n", max_freq);
+}
+static DEVICE_ATTR_RW(max_freq);
+
+static ssize_t available_frequencies_show(struct device *d,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct devfreq *df = to_devfreq(d);
+	ssize_t count = 0;
+	int i;
+
+	if (!df->profile)
+		return -EINVAL;
+
+	mutex_lock(&df->lock);
+
+	for (i = 0; i < df->max_state; i++)
+		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+				"%lu ", df->freq_table[i]);
+
+	mutex_unlock(&df->lock);
+	/* Truncate the trailing space */
+	if (count)
+		count--;
+
+	count += sprintf(&buf[count], "\n");
+
+	return count;
+}
+static DEVICE_ATTR_RO(available_frequencies);
+
+static ssize_t trans_stat_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+	ssize_t len = 0;
+	int i, j;
+	unsigned int max_state;
+
+	if (!df->profile)
+		return -EINVAL;
+	max_state = df->max_state;
+
+	if (max_state == 0)
+		return scnprintf(buf, PAGE_SIZE, "Not Supported.\n");
+
+	mutex_lock(&df->lock);
+	if (!df->stop_polling &&
+			devfreq_update_status(df, df->previous_freq)) {
+		mutex_unlock(&df->lock);
+		return 0;
+	}
+	mutex_unlock(&df->lock);
+
+	len += scnprintf(buf + len, PAGE_SIZE - len, "     From  :   To\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "           :");
+	for (i = 0; i < max_state; i++) {
+		if (len >= PAGE_SIZE - 1)
+			break;
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu",
+				 df->freq_table[i]);
+	}
+	if (len >= PAGE_SIZE - 1)
+		return PAGE_SIZE - 1;
+
+	len += scnprintf(buf + len, PAGE_SIZE - len, "   time(ms)\n");
+
+	for (i = 0; i < max_state; i++) {
+		if (len >= PAGE_SIZE - 1)
+			break;
+		if (df->freq_table[i] == df->previous_freq)
+			len += scnprintf(buf + len, PAGE_SIZE - len, "*");
+		else
+			len += scnprintf(buf + len, PAGE_SIZE - len, " ");
+		if (len >= PAGE_SIZE - 1)
+			break;
+
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu:",
+				 df->freq_table[i]);
+		for (j = 0; j < max_state; j++) {
+			if (len >= PAGE_SIZE - 1)
+				break;
+			len += scnprintf(buf + len, PAGE_SIZE - len, "%10u",
+					 df->stats.trans_table[(i * max_state) + j]);
+		}
+		if (len >= PAGE_SIZE - 1)
+			break;
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%10llu\n", (u64)
+				 jiffies64_to_msecs(df->stats.time_in_state[i]));
+	}
+
+	if (len < PAGE_SIZE - 1)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "Total transition : %u\n",
+				 df->stats.total_trans);
+
+	if (len >= PAGE_SIZE - 1) {
+		pr_warn_once("devfreq transition table exceeds PAGE_SIZE. Disabling\n");
+		return -EFBIG;
+	}
+
+	return len;
+}
+
+static ssize_t trans_stat_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	int err, value;
+
+	if (!df->profile)
+		return -EINVAL;
+
+	if (df->max_state == 0)
+		return count;
+
+	err = kstrtoint(buf, 10, &value);
+	if (err || value != 0)
+		return -EINVAL;
+
+	mutex_lock(&df->lock);
+	memset(df->stats.time_in_state, 0, (df->max_state *
+					sizeof(*df->stats.time_in_state)));
+	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
+					df->max_state,
+					df->max_state));
+	df->stats.total_trans = 0;
+	df->stats.last_update = get_jiffies_64();
+	mutex_unlock(&df->lock);
+
+	return count;
+}
+static DEVICE_ATTR_RW(trans_stat);
+
+static struct attribute *devfreq_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_governor.attr,
+	&dev_attr_available_governors.attr,
+	&dev_attr_cur_freq.attr,
+	&dev_attr_available_frequencies.attr,
+	&dev_attr_target_freq.attr,
+	&dev_attr_min_freq.attr,
+	&dev_attr_max_freq.attr,
+	&dev_attr_trans_stat.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(devfreq);
+
+static ssize_t polling_interval_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+
+	if (!df->profile)
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n", df->profile->polling_ms);
+}
+
+static ssize_t polling_interval_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned int value;
+	int ret;
+
+	if (!df->governor)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%u", &value);
+	if (ret != 1)
+		return -EINVAL;
+
+	df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
+	ret = count;
+
+	return ret;
+}
+static DEVICE_ATTR_RW(polling_interval);
+
+static ssize_t timer_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct devfreq *df = to_devfreq(dev);
+
+	if (!df->profile)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
+}
+
+static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	char str_timer[DEVFREQ_NAME_LEN + 1];
+	int timer = -1;
+	int ret = 0, i;
+
+	if (!df->governor || !df->profile)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%16s", str_timer);
+	if (ret != 1)
+		return -EINVAL;
+
+	for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
+		if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
+			timer = i;
+			break;
+		}
+	}
+
+	if (timer < 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (df->profile->timer == timer) {
+		ret = 0;
+		goto out;
+	}
+
+	mutex_lock(&df->lock);
+	df->profile->timer = timer;
+	mutex_unlock(&df->lock);
+
+	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
+	if (ret) {
+		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
+			 __func__, df->governor->name, ret);
+		goto out;
+	}
+
+	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+	if (ret)
+		dev_warn(dev, "%s: Governor %s not started(%d)\n",
+			 __func__, df->governor->name, ret);
+out:
+	return ret ? ret : count;
+}
+static DEVICE_ATTR_RW(timer);
+
+#define CREATE_SYSFS_FILE(df, name)					\
+{									\
+	int ret;							\
+	ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);	\
+	if (ret < 0) {							\
+		dev_warn(&df->dev,					\
+			"Unable to create attr(%s)\n", "##name");	\
+	}								\
+}									\
+
+/* Create the specific sysfs files which depend on each governor. */
+static void create_sysfs_files(struct devfreq *devfreq,
+				const struct devfreq_governor *gov)
+{
+	if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+		CREATE_SYSFS_FILE(devfreq, polling_interval);
+	if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+		CREATE_SYSFS_FILE(devfreq, timer);
+}
+
+/* Remove the specific sysfs files which depend on each governor. */
+static void remove_sysfs_files(struct devfreq *devfreq,
+				const struct devfreq_governor *gov)
+{
+	if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+		sysfs_remove_file(&devfreq->dev.kobj,
+				&dev_attr_polling_interval.attr);
+	if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+		sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
+}
+
+/**
+ * devfreq_summary_show() - Show the summary of the devfreq devices
+ * @s:		seq_file instance to show the summary of devfreq devices
+ * @data:	not used
+ *
+ * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
+ * It helps that user can know the detailed information of the devfreq devices.
+ *
+ * Return 0 always because it shows the information without any data change.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+	struct devfreq *devfreq;
+	struct devfreq *p_devfreq = NULL;
+	unsigned long cur_freq, min_freq, max_freq;
+	unsigned int polling_ms;
+	unsigned int timer;
+
+	seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
+			"dev",
+			"parent_dev",
+			"governor",
+			"timer",
+			"polling_ms",
+			"cur_freq_Hz",
+			"min_freq_Hz",
+			"max_freq_Hz");
+	seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
+			"------------------------------",
+			"------------------------------",
+			"---------------",
+			"----------",
+			"----------",
+			"------------",
+			"------------",
+			"------------");
+
+	mutex_lock(&devfreq_list_lock);
+
+	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
+		if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
+							DEVFREQ_NAME_LEN)) {
+			struct devfreq_passive_data *data = devfreq->data;
+
+			if (data)
+				p_devfreq = data->parent;
+		} else {
+			p_devfreq = NULL;
+		}
+#endif
+
+		mutex_lock(&devfreq->lock);
+		cur_freq = devfreq->previous_freq;
+		devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+		timer = devfreq->profile->timer;
+
+		if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
+			polling_ms = devfreq->profile->polling_ms;
+		else
+			polling_ms = 0;
+		mutex_unlock(&devfreq->lock);
+
+		seq_printf(s,
+			"%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
+			dev_name(&devfreq->dev),
+			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
+			devfreq->governor->name,
+			polling_ms ? timer_name[timer] : "null",
+			polling_ms,
+			cur_freq,
+			min_freq,
+			max_freq);
+	}
+
+	mutex_unlock(&devfreq_list_lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
+static int __init devfreq_init(void)
+{
+	devfreq_class = class_create(THIS_MODULE, "devfreq");
+	if (IS_ERR(devfreq_class)) {
+		pr_err("%s: couldn't create class\n", __FILE__);
+		return PTR_ERR(devfreq_class);
+	}
+
+	devfreq_wq = create_freezable_workqueue("devfreq_wq");
+	if (!devfreq_wq) {
+		class_destroy(devfreq_class);
+		pr_err("%s: couldn't create workqueue\n", __FILE__);
+		return -ENOMEM;
+	}
+	devfreq_class->dev_groups = devfreq_groups;
+
+	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+	debugfs_create_file("devfreq_summary", 0444,
+				devfreq_debugfs, NULL,
+				&devfreq_summary_fops);
+
+	return 0;
+}
+subsys_initcall(devfreq_init);
+
+/*
+ * The following are helper functions for devfreq user device drivers with
+ * OPP framework.
+ */
+
+/**
+ * devfreq_recommended_opp() - Helper function to get proper OPP for the
+ *			     freq value given to target callback.
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @freq:	The frequency given to target function
+ * @flags:	Flags handed from devfreq framework.
+ *
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
+ */
+struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
+					   unsigned long *freq,
+					   u32 flags)
+{
+	struct dev_pm_opp *opp;
+
+	if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
+		/* The freq is an upper bound. opp should be lower */
+		opp = dev_pm_opp_find_freq_floor(dev, freq);
+
+		/* If not available, use the closest opp */
+		if (opp == ERR_PTR(-ERANGE))
+			opp = dev_pm_opp_find_freq_ceil(dev, freq);
+	} else {
+		/* The freq is an lower bound. opp should be higher */
+		opp = dev_pm_opp_find_freq_ceil(dev, freq);
+
+		/* If not available, use the closest opp */
+		if (opp == ERR_PTR(-ERANGE))
+			opp = dev_pm_opp_find_freq_floor(dev, freq);
+	}
+
+	return opp;
+}
+EXPORT_SYMBOL(devfreq_recommended_opp);
+
+/**
+ * devfreq_register_opp_notifier() - Helper function to get devfreq notified
+ *				     for any changes in the OPP availability
+ *				     changes
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ */
+int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
+{
+	return dev_pm_opp_register_notifier(dev, &devfreq->nb);
+}
+EXPORT_SYMBOL(devfreq_register_opp_notifier);
+
+/**
+ * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
+ *				       notified for any changes in the OPP
+ *				       availability changes anymore.
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ *
+ * At exit() callback of devfreq_dev_profile, this must be included if
+ * devfreq_recommended_opp is used.
+ */
+int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
+{
+	return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
+}
+EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
+
+static void devm_devfreq_opp_release(struct device *dev, void *res)
+{
+	devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
+}
+
+/**
+ * devm_devfreq_register_opp_notifier() - Resource-managed
+ *					  devfreq_register_opp_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ */
+int devm_devfreq_register_opp_notifier(struct device *dev,
+				       struct devfreq *devfreq)
+{
+	struct devfreq **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = devfreq_register_opp_notifier(dev, devfreq);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = devfreq;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
+
+/**
+ * devm_devfreq_unregister_opp_notifier() - Resource-managed
+ *					    devfreq_unregister_opp_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ */
+void devm_devfreq_unregister_opp_notifier(struct device *dev,
+					 struct devfreq *devfreq)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_opp_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
+
+/**
+ * devfreq_register_notifier() - Register a driver with devfreq
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to register.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_register_notifier(struct devfreq *devfreq,
+			      struct notifier_block *nb,
+			      unsigned int list)
+{
+	int ret = 0;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (list) {
+	case DEVFREQ_TRANSITION_NOTIFIER:
+		ret = srcu_notifier_chain_register(
+				&devfreq->transition_notifier_list, nb);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devfreq_register_notifier);
+
+/*
+ * devfreq_unregister_notifier() - Unregister a driver with devfreq
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_unregister_notifier(struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	int ret = 0;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (list) {
+	case DEVFREQ_TRANSITION_NOTIFIER:
+		ret = srcu_notifier_chain_unregister(
+				&devfreq->transition_notifier_list, nb);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devfreq_unregister_notifier);
+
+struct devfreq_notifier_devres {
+	struct devfreq *devfreq;
+	struct notifier_block *nb;
+	unsigned int list;
+};
+
+static void devm_devfreq_notifier_release(struct device *dev, void *res)
+{
+	struct devfreq_notifier_devres *this = res;
+
+	devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
+}
+
+/**
+ * devm_devfreq_register_notifier()
+ *	- Resource-managed devfreq_register_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devm_devfreq_register_notifier(struct device *dev,
+				struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	struct devfreq_notifier_devres *ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
+				GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = devfreq_register_notifier(devfreq, nb, list);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	ptr->devfreq = devfreq;
+	ptr->nb = nb;
+	ptr->list = list;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_notifier);
+
+/**
+ * devm_devfreq_unregister_notifier()
+ *	- Resource-managed devfreq_unregister_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+void devm_devfreq_unregister_notifier(struct device *dev,
+				      struct devfreq *devfreq,
+				      struct notifier_block *nb,
+				      unsigned int list)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_notifier);
diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
new file mode 100644
index 000000000..878825372
--- /dev/null
+++ b/drivers/devfreq/event/Kconfig
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig PM_DEVFREQ_EVENT
+	bool "DEVFREQ-Event device Support"
+	help
+	  The devfreq-event device provide the raw data and events which
+	  indicate the current state of devfreq-event device. The provided
+	  data from devfreq-event device is used to monitor the state of
+	  device and determine the suitable size of resource to reduce the
+	  wasted resource.
+
+	  The devfreq-event device can support the various type of events
+	  (e.g., raw data, utilization, latency, bandwidth). The events
+	  may be used by devfreq governor and other subsystem.
+
+if PM_DEVFREQ_EVENT
+
+config DEVFREQ_EVENT_EXYNOS_NOCP
+	tristate "Exynos NoC (Network On Chip) Probe DEVFREQ event Driver"
+	depends on ARCH_EXYNOS || COMPILE_TEST
+	select PM_OPP
+	select REGMAP_MMIO
+	help
+	  This add the devfreq-event driver for Exynos SoC. It provides NoC
+	  (Network on Chip) Probe counters to measure the bandwidth of AXI bus.
+
+config DEVFREQ_EVENT_EXYNOS_PPMU
+	tristate "Exynos PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
+	depends on ARCH_EXYNOS || COMPILE_TEST
+	select PM_OPP
+	help
+	  This add the devfreq-event driver for Exynos SoC. It provides PPMU
+	  (Platform Performance Monitoring Unit) counters to estimate the
+	  utilization of each module.
+
+config DEVFREQ_EVENT_ROCKCHIP_DFI
+	tristate "ROCKCHIP DFI DEVFREQ event Driver"
+	depends on ARCH_ROCKCHIP || COMPILE_TEST
+	help
+	  This add the devfreq-event driver for Rockchip SoC. It provides DFI
+	  (DDR Monitor Module) driver to count ddr load.
+
+endif # PM_DEVFREQ_EVENT
diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
new file mode 100644
index 000000000..3c847e5d5
--- /dev/null
+++ b/drivers/devfreq/event/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Exynos DEVFREQ Event Drivers
+
+obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_NOCP) += exynos-nocp.o
+obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_PPMU) += exynos-ppmu.o
+obj-$(CONFIG_DEVFREQ_EVENT_ROCKCHIP_DFI) += rockchip-dfi.o
diff --git a/drivers/devfreq/event/exynos-nocp.c b/drivers/devfreq/event/exynos-nocp.c
new file mode 100644
index 000000000..ccc531ee6
--- /dev/null
+++ b/drivers/devfreq/event/exynos-nocp.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * exynos-nocp.c - Exynos NoC (Network On Chip) Probe support
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "exynos-nocp.h"
+
+struct exynos_nocp {
+	struct devfreq_event_dev *edev;
+	struct devfreq_event_desc desc;
+
+	struct device *dev;
+
+	struct regmap *regmap;
+	struct clk *clk;
+};
+
+/*
+ * The devfreq-event ops structure for nocp probe.
+ */
+static int exynos_nocp_set_event(struct devfreq_event_dev *edev)
+{
+	struct exynos_nocp *nocp = devfreq_event_get_drvdata(edev);
+	int ret;
+
+	/* Disable NoC probe */
+	ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
+				NOCP_MAIN_CTL_STATEN_MASK, 0);
+	if (ret < 0) {
+		dev_err(nocp->dev, "failed to disable the NoC probe device\n");
+		return ret;
+	}
+
+	/* Set a statistics dump period to 0 */
+	ret = regmap_write(nocp->regmap, NOCP_STAT_PERIOD, 0x0);
+	if (ret < 0)
+		goto out;
+
+	/* Set the IntEvent fields of *_SRC */
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_0_SRC,
+				NOCP_CNT_SRC_INTEVENT_MASK,
+				NOCP_CNT_SRC_INTEVENT_BYTE_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_1_SRC,
+				NOCP_CNT_SRC_INTEVENT_MASK,
+				NOCP_CNT_SRC_INTEVENT_CHAIN_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_2_SRC,
+				NOCP_CNT_SRC_INTEVENT_MASK,
+				NOCP_CNT_SRC_INTEVENT_CYCLE_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_3_SRC,
+				NOCP_CNT_SRC_INTEVENT_MASK,
+				NOCP_CNT_SRC_INTEVENT_CHAIN_MASK);
+	if (ret < 0)
+		goto out;
+
+
+	/* Set an alarm with a max/min value of 0 to generate StatALARM */
+	ret = regmap_write(nocp->regmap, NOCP_STAT_ALARM_MIN, 0x0);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_write(nocp->regmap, NOCP_STAT_ALARM_MAX, 0x0);
+	if (ret < 0)
+		goto out;
+
+	/* Set AlarmMode */
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_0_ALARM_MODE,
+				NOCP_CNT_ALARM_MODE_MASK,
+				NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_1_ALARM_MODE,
+				NOCP_CNT_ALARM_MODE_MASK,
+				NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_2_ALARM_MODE,
+				NOCP_CNT_ALARM_MODE_MASK,
+				NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_3_ALARM_MODE,
+				NOCP_CNT_ALARM_MODE_MASK,
+				NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
+	if (ret < 0)
+		goto out;
+
+	/* Enable the measurements by setting AlarmEn and StatEn */
+	ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
+			NOCP_MAIN_CTL_STATEN_MASK | NOCP_MAIN_CTL_ALARMEN_MASK,
+			NOCP_MAIN_CTL_STATEN_MASK | NOCP_MAIN_CTL_ALARMEN_MASK);
+	if (ret < 0)
+		goto out;
+
+	/* Set GlobalEN */
+	ret = regmap_update_bits(nocp->regmap, NOCP_CFG_CTL,
+				NOCP_CFG_CTL_GLOBALEN_MASK,
+				NOCP_CFG_CTL_GLOBALEN_MASK);
+	if (ret < 0)
+		goto out;
+
+	/* Enable NoC probe */
+	ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
+				NOCP_MAIN_CTL_STATEN_MASK,
+				NOCP_MAIN_CTL_STATEN_MASK);
+	if (ret < 0)
+		goto out;
+
+	return 0;
+
+out:
+	/* Reset NoC probe */
+	if (regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
+				NOCP_MAIN_CTL_STATEN_MASK, 0)) {
+		dev_err(nocp->dev, "Failed to reset NoC probe device\n");
+	}
+
+	return ret;
+}
+
+static int exynos_nocp_get_event(struct devfreq_event_dev *edev,
+				struct devfreq_event_data *edata)
+{
+	struct exynos_nocp *nocp = devfreq_event_get_drvdata(edev);
+	unsigned int counter[4];
+	int ret;
+
+	/* Read cycle count */
+	ret = regmap_read(nocp->regmap, NOCP_COUNTERS_0_VAL, &counter[0]);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_read(nocp->regmap, NOCP_COUNTERS_1_VAL, &counter[1]);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_read(nocp->regmap, NOCP_COUNTERS_2_VAL, &counter[2]);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_read(nocp->regmap, NOCP_COUNTERS_3_VAL, &counter[3]);
+	if (ret < 0)
+		goto out;
+
+	edata->load_count = ((counter[1] << 16) | counter[0]);
+	edata->total_count = ((counter[3] << 16) | counter[2]);
+
+	dev_dbg(&edev->dev, "%s (event: %ld/%ld)\n", edev->desc->name,
+					edata->load_count, edata->total_count);
+
+	return 0;
+
+out:
+	dev_err(nocp->dev, "Failed to read the counter of NoC probe device\n");
+
+	return ret;
+}
+
+static const struct devfreq_event_ops exynos_nocp_ops = {
+	.set_event = exynos_nocp_set_event,
+	.get_event = exynos_nocp_get_event,
+};
+
+static const struct of_device_id exynos_nocp_id_match[] = {
+	{ .compatible = "samsung,exynos5420-nocp", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, exynos_nocp_id_match);
+
+static struct regmap_config exynos_nocp_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = NOCP_COUNTERS_3_VAL,
+};
+
+static int exynos_nocp_parse_dt(struct platform_device *pdev,
+				struct exynos_nocp *nocp)
+{
+	struct device *dev = nocp->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *res;
+	void __iomem *base;
+
+	if (!np) {
+		dev_err(dev, "failed to find devicetree node\n");
+		return -EINVAL;
+	}
+
+	nocp->clk = devm_clk_get(dev, "nocp");
+	if (IS_ERR(nocp->clk))
+		nocp->clk = NULL;
+
+	/* Maps the memory mapped IO to control nocp register */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	exynos_nocp_regmap_config.max_register = resource_size(res) - 4;
+
+	nocp->regmap = devm_regmap_init_mmio(dev, base,
+					&exynos_nocp_regmap_config);
+	if (IS_ERR(nocp->regmap)) {
+		dev_err(dev, "failed to initialize regmap\n");
+		return PTR_ERR(nocp->regmap);
+	}
+
+	return 0;
+}
+
+static int exynos_nocp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct exynos_nocp *nocp;
+	int ret;
+
+	nocp = devm_kzalloc(&pdev->dev, sizeof(*nocp), GFP_KERNEL);
+	if (!nocp)
+		return -ENOMEM;
+
+	nocp->dev = &pdev->dev;
+
+	/* Parse dt data to get resource */
+	ret = exynos_nocp_parse_dt(pdev, nocp);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"failed to parse devicetree for resource\n");
+		return ret;
+	}
+
+	/* Add devfreq-event device to measure the bandwidth of NoC */
+	nocp->desc.ops = &exynos_nocp_ops;
+	nocp->desc.driver_data = nocp;
+	nocp->desc.name = np->full_name;
+	nocp->edev = devm_devfreq_event_add_edev(&pdev->dev, &nocp->desc);
+	if (IS_ERR(nocp->edev)) {
+		dev_err(&pdev->dev,
+			"failed to add devfreq-event device\n");
+		return PTR_ERR(nocp->edev);
+	}
+	platform_set_drvdata(pdev, nocp);
+
+	ret = clk_prepare_enable(nocp->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to prepare ppmu clock\n");
+		return ret;
+	}
+
+	pr_info("exynos-nocp: new NoC Probe device registered: %s\n",
+			dev_name(dev));
+
+	return 0;
+}
+
+static int exynos_nocp_remove(struct platform_device *pdev)
+{
+	struct exynos_nocp *nocp = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(nocp->clk);
+
+	return 0;
+}
+
+static struct platform_driver exynos_nocp_driver = {
+	.probe	= exynos_nocp_probe,
+	.remove	= exynos_nocp_remove,
+	.driver = {
+		.name	= "exynos-nocp",
+		.of_match_table = exynos_nocp_id_match,
+	},
+};
+module_platform_driver(exynos_nocp_driver);
+
+MODULE_DESCRIPTION("Exynos NoC (Network on Chip) Probe driver");
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/event/exynos-nocp.h b/drivers/devfreq/event/exynos-nocp.h
new file mode 100644
index 000000000..2d6f08cfd
--- /dev/null
+++ b/drivers/devfreq/event/exynos-nocp.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * exynos-nocp.h - Exynos NoC (Network on Chip) Probe header file
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ */
+
+#ifndef __EXYNOS_NOCP_H__
+#define __EXYNOS_NOCP_H__
+
+enum nocp_reg {
+	NOCP_ID_REVISION_ID		= 0x04,
+	NOCP_MAIN_CTL			= 0x08,
+	NOCP_CFG_CTL			= 0x0C,
+
+	NOCP_STAT_PERIOD		= 0x24,
+	NOCP_STAT_GO			= 0x28,
+	NOCP_STAT_ALARM_MIN		= 0x2C,
+	NOCP_STAT_ALARM_MAX		= 0x30,
+	NOCP_STAT_ALARM_STATUS		= 0x34,
+	NOCP_STAT_ALARM_CLR		= 0x38,
+
+	NOCP_COUNTERS_0_SRC		= 0x138,
+	NOCP_COUNTERS_0_ALARM_MODE	= 0x13C,
+	NOCP_COUNTERS_0_VAL		= 0x140,
+
+	NOCP_COUNTERS_1_SRC		= 0x14C,
+	NOCP_COUNTERS_1_ALARM_MODE	= 0x150,
+	NOCP_COUNTERS_1_VAL		= 0x154,
+
+	NOCP_COUNTERS_2_SRC		= 0x160,
+	NOCP_COUNTERS_2_ALARM_MODE	= 0x164,
+	NOCP_COUNTERS_2_VAL		= 0x168,
+
+	NOCP_COUNTERS_3_SRC		= 0x174,
+	NOCP_COUNTERS_3_ALARM_MODE	= 0x178,
+	NOCP_COUNTERS_3_VAL		= 0x17C,
+};
+
+/* NOCP_MAIN_CTL register */
+#define NOCP_MAIN_CTL_ERREN_MASK		BIT(0)
+#define NOCP_MAIN_CTL_TRACEEN_MASK		BIT(1)
+#define NOCP_MAIN_CTL_PAYLOADEN_MASK		BIT(2)
+#define NOCP_MAIN_CTL_STATEN_MASK		BIT(3)
+#define NOCP_MAIN_CTL_ALARMEN_MASK		BIT(4)
+#define NOCP_MAIN_CTL_STATCONDDUMP_MASK	BIT(5)
+#define NOCP_MAIN_CTL_INTRUSIVEMODE_MASK	BIT(6)
+
+/* NOCP_CFG_CTL register */
+#define NOCP_CFG_CTL_GLOBALEN_MASK		BIT(0)
+#define NOCP_CFG_CTL_ACTIVE_MASK		BIT(1)
+
+/* NOCP_COUNTERS_x_SRC register */
+#define NOCP_CNT_SRC_INTEVENT_SHIFT		0
+#define NOCP_CNT_SRC_INTEVENT_MASK		(0x1F << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_OFF_MASK		(0x0 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_CYCLE_MASK	(0x1 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_IDLE_MASK		(0x2 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_XFER_MASK		(0x3 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_BUSY_MASK		(0x4 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_WAIT_MASK		(0x5 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_PKT_MASK		(0x6 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_BYTE_MASK		(0x8 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+#define NOCP_CNT_SRC_INTEVENT_CHAIN_MASK	(0x10 << NOCP_CNT_SRC_INTEVENT_SHIFT)
+
+/* NOCP_COUNTERS_x_ALARM_MODE register */
+#define NOCP_CNT_ALARM_MODE_SHIFT		0
+#define NOCP_CNT_ALARM_MODE_MASK		(0x3 << NOCP_CNT_ALARM_MODE_SHIFT)
+#define NOCP_CNT_ALARM_MODE_OFF_MASK		(0x0 << NOCP_CNT_ALARM_MODE_SHIFT)
+#define NOCP_CNT_ALARM_MODE_MIN_MASK		(0x1 << NOCP_CNT_ALARM_MODE_SHIFT)
+#define NOCP_CNT_ALARM_MODE_MAX_MASK		(0x2 << NOCP_CNT_ALARM_MODE_SHIFT)
+#define NOCP_CNT_ALARM_MODE_MIN_MAX_MASK	(0x3 << NOCP_CNT_ALARM_MODE_SHIFT)
+
+#endif /* __EXYNOS_NOCP_H__ */
diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c
new file mode 100644
index 000000000..a443e7c42
--- /dev/null
+++ b/drivers/devfreq/event/exynos-ppmu.c
@@ -0,0 +1,724 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * exynos_ppmu.c - Exynos PPMU (Platform Performance Monitoring Unit) support
+ *
+ * Copyright (c) 2014-2015 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This driver is based on drivers/devfreq/exynos/exynos_ppmu.c
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/suspend.h>
+#include <linux/devfreq-event.h>
+
+#include "exynos-ppmu.h"
+
+enum exynos_ppmu_type {
+	EXYNOS_TYPE_PPMU,
+	EXYNOS_TYPE_PPMU_V2,
+};
+
+struct exynos_ppmu_data {
+	struct clk *clk;
+};
+
+struct exynos_ppmu {
+	struct devfreq_event_dev **edev;
+	struct devfreq_event_desc *desc;
+	unsigned int num_events;
+
+	struct device *dev;
+	struct regmap *regmap;
+
+	struct exynos_ppmu_data ppmu;
+	enum exynos_ppmu_type ppmu_type;
+};
+
+#define PPMU_EVENT(name)			\
+	{ "ppmu-event0-"#name, PPMU_PMNCNT0 },	\
+	{ "ppmu-event1-"#name, PPMU_PMNCNT1 },	\
+	{ "ppmu-event2-"#name, PPMU_PMNCNT2 },	\
+	{ "ppmu-event3-"#name, PPMU_PMNCNT3 }
+
+static struct __exynos_ppmu_events {
+	char *name;
+	int id;
+} ppmu_events[] = {
+	/* For Exynos3250, Exynos4 and Exynos5260 */
+	PPMU_EVENT(g3d),
+	PPMU_EVENT(fsys),
+
+	/* For Exynos4 SoCs and Exynos3250 */
+	PPMU_EVENT(dmc0),
+	PPMU_EVENT(dmc1),
+	PPMU_EVENT(cpu),
+	PPMU_EVENT(rightbus),
+	PPMU_EVENT(leftbus),
+	PPMU_EVENT(lcd0),
+	PPMU_EVENT(camif),
+
+	/* Only for Exynos3250 and Exynos5260 */
+	PPMU_EVENT(mfc),
+
+	/* Only for Exynos4 SoCs */
+	PPMU_EVENT(mfc-left),
+	PPMU_EVENT(mfc-right),
+
+	/* Only for Exynos5260 SoCs */
+	PPMU_EVENT(drex0-s0),
+	PPMU_EVENT(drex0-s1),
+	PPMU_EVENT(drex1-s0),
+	PPMU_EVENT(drex1-s1),
+	PPMU_EVENT(eagle),
+	PPMU_EVENT(kfc),
+	PPMU_EVENT(isp),
+	PPMU_EVENT(fimc),
+	PPMU_EVENT(gscl),
+	PPMU_EVENT(mscl),
+	PPMU_EVENT(fimd0x),
+	PPMU_EVENT(fimd1x),
+
+	/* Only for Exynos5433 SoCs */
+	PPMU_EVENT(d0-cpu),
+	PPMU_EVENT(d0-general),
+	PPMU_EVENT(d0-rt),
+	PPMU_EVENT(d1-cpu),
+	PPMU_EVENT(d1-general),
+	PPMU_EVENT(d1-rt),
+
+	/* For Exynos5422 SoC, deprecated (backwards compatible) */
+	PPMU_EVENT(dmc0_0),
+	PPMU_EVENT(dmc0_1),
+	PPMU_EVENT(dmc1_0),
+	PPMU_EVENT(dmc1_1),
+	/* For Exynos5422 SoC */
+	PPMU_EVENT(dmc0-0),
+	PPMU_EVENT(dmc0-1),
+	PPMU_EVENT(dmc1-0),
+	PPMU_EVENT(dmc1-1),
+};
+
+static int __exynos_ppmu_find_ppmu_id(const char *edev_name)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ppmu_events); i++)
+		if (!strcmp(edev_name, ppmu_events[i].name))
+			return ppmu_events[i].id;
+
+	return -EINVAL;
+}
+
+static int exynos_ppmu_find_ppmu_id(struct devfreq_event_dev *edev)
+{
+	return __exynos_ppmu_find_ppmu_id(edev->desc->name);
+}
+
+/*
+ * The devfreq-event ops structure for PPMU v1.1
+ */
+static int exynos_ppmu_disable(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int ret;
+	u32 pmnc;
+
+	/* Disable all counters */
+	ret = regmap_write(info->regmap, PPMU_CNTENC,
+				PPMU_CCNT_MASK |
+				PPMU_PMCNT0_MASK |
+				PPMU_PMCNT1_MASK |
+				PPMU_PMCNT2_MASK |
+				PPMU_PMCNT3_MASK);
+	if (ret < 0)
+		return ret;
+
+	/* Disable PPMU */
+	ret = regmap_read(info->regmap, PPMU_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	ret = regmap_write(info->regmap, PPMU_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int exynos_ppmu_set_event(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	int ret;
+	u32 pmnc, cntens;
+
+	if (id < 0)
+		return id;
+
+	/* Enable specific counter */
+	ret = regmap_read(info->regmap, PPMU_CNTENS, &cntens);
+	if (ret < 0)
+		return ret;
+
+	cntens |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	ret = regmap_write(info->regmap, PPMU_CNTENS, cntens);
+	if (ret < 0)
+		return ret;
+
+	/* Set the event of proper data type monitoring */
+	ret = regmap_write(info->regmap, PPMU_BEVTxSEL(id),
+			   edev->desc->event_type);
+	if (ret < 0)
+		return ret;
+
+	/* Reset cycle counter/performance counter and enable PPMU */
+	ret = regmap_read(info->regmap, PPMU_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~(PPMU_PMNC_ENABLE_MASK
+			| PPMU_PMNC_COUNTER_RESET_MASK
+			| PPMU_PMNC_CC_RESET_MASK);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_ENABLE_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_COUNTER_RESET_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_CC_RESET_SHIFT);
+	ret = regmap_write(info->regmap, PPMU_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int exynos_ppmu_get_event(struct devfreq_event_dev *edev,
+				struct devfreq_event_data *edata)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	unsigned int total_count, load_count;
+	unsigned int pmcnt3_high, pmcnt3_low;
+	unsigned int pmnc, cntenc;
+	int ret;
+
+	if (id < 0)
+		return -EINVAL;
+
+	/* Disable PPMU */
+	ret = regmap_read(info->regmap, PPMU_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	ret = regmap_write(info->regmap, PPMU_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	/* Read cycle count */
+	ret = regmap_read(info->regmap, PPMU_CCNT, &total_count);
+	if (ret < 0)
+		return ret;
+	edata->total_count = total_count;
+
+	/* Read performance count */
+	switch (id) {
+	case PPMU_PMNCNT0:
+	case PPMU_PMNCNT1:
+	case PPMU_PMNCNT2:
+		ret = regmap_read(info->regmap, PPMU_PMNCT(id), &load_count);
+		if (ret < 0)
+			return ret;
+		edata->load_count = load_count;
+		break;
+	case PPMU_PMNCNT3:
+		ret = regmap_read(info->regmap, PPMU_PMCNT3_HIGH, &pmcnt3_high);
+		if (ret < 0)
+			return ret;
+
+		ret = regmap_read(info->regmap, PPMU_PMCNT3_LOW, &pmcnt3_low);
+		if (ret < 0)
+			return ret;
+
+		edata->load_count = ((pmcnt3_high << 8) | pmcnt3_low);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Disable specific counter */
+	ret = regmap_read(info->regmap, PPMU_CNTENC, &cntenc);
+	if (ret < 0)
+		return ret;
+
+	cntenc |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	ret = regmap_write(info->regmap, PPMU_CNTENC, cntenc);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&edev->dev, "%s (event: %ld/%ld)\n", edev->desc->name,
+					edata->load_count, edata->total_count);
+
+	return 0;
+}
+
+static const struct devfreq_event_ops exynos_ppmu_ops = {
+	.disable = exynos_ppmu_disable,
+	.set_event = exynos_ppmu_set_event,
+	.get_event = exynos_ppmu_get_event,
+};
+
+/*
+ * The devfreq-event ops structure for PPMU v2.0
+ */
+static int exynos_ppmu_v2_disable(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int ret;
+	u32 pmnc, clear;
+
+	/* Disable all counters */
+	clear = (PPMU_CCNT_MASK | PPMU_PMCNT0_MASK | PPMU_PMCNT1_MASK
+		| PPMU_PMCNT2_MASK | PPMU_PMCNT3_MASK);
+	ret = regmap_write(info->regmap, PPMU_V2_FLAG, clear);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_INTENC, clear);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CNTENC, clear);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CNT_RESET, clear);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CIG_CFG0, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CIG_CFG1, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CIG_CFG2, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CIG_RESULT, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CNT_AUTO, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CH_EV0_TYPE, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CH_EV1_TYPE, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CH_EV2_TYPE, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_CH_EV3_TYPE, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_SM_ID_V, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_SM_ID_A, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_SM_OTHERS_V, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_SM_OTHERS_A, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, PPMU_V2_INTERRUPT_RESET, 0x0);
+	if (ret < 0)
+		return ret;
+
+	/* Disable PPMU */
+	ret = regmap_read(info->regmap, PPMU_V2_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	ret = regmap_write(info->regmap, PPMU_V2_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int exynos_ppmu_v2_set_event(struct devfreq_event_dev *edev)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	unsigned int pmnc, cntens;
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	int ret;
+
+	/* Enable all counters */
+	ret = regmap_read(info->regmap, PPMU_V2_CNTENS, &cntens);
+	if (ret < 0)
+		return ret;
+
+	cntens |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	ret = regmap_write(info->regmap, PPMU_V2_CNTENS, cntens);
+	if (ret < 0)
+		return ret;
+
+	/* Set the event of proper data type monitoring */
+	ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
+			   edev->desc->event_type);
+	if (ret < 0)
+		return ret;
+
+	/* Reset cycle counter/performance counter and enable PPMU */
+	ret = regmap_read(info->regmap, PPMU_V2_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~(PPMU_PMNC_ENABLE_MASK
+			| PPMU_PMNC_COUNTER_RESET_MASK
+			| PPMU_PMNC_CC_RESET_MASK
+			| PPMU_PMNC_CC_DIVIDER_MASK
+			| PPMU_V2_PMNC_START_MODE_MASK);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_ENABLE_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_COUNTER_RESET_SHIFT);
+	pmnc |= (PPMU_ENABLE << PPMU_PMNC_CC_RESET_SHIFT);
+	pmnc |= (PPMU_V2_MODE_MANUAL << PPMU_V2_PMNC_START_MODE_SHIFT);
+
+	ret = regmap_write(info->regmap, PPMU_V2_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int exynos_ppmu_v2_get_event(struct devfreq_event_dev *edev,
+				    struct devfreq_event_data *edata)
+{
+	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
+	int id = exynos_ppmu_find_ppmu_id(edev);
+	int ret;
+	unsigned int pmnc, cntenc;
+	unsigned int pmcnt_high, pmcnt_low;
+	unsigned int total_count, count;
+	unsigned long load_count = 0;
+
+	/* Disable PPMU */
+	ret = regmap_read(info->regmap, PPMU_V2_PMNC, &pmnc);
+	if (ret < 0)
+		return ret;
+
+	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
+	ret = regmap_write(info->regmap, PPMU_V2_PMNC, pmnc);
+	if (ret < 0)
+		return ret;
+
+	/* Read cycle count and performance count */
+	ret = regmap_read(info->regmap, PPMU_V2_CCNT, &total_count);
+	if (ret < 0)
+		return ret;
+	edata->total_count = total_count;
+
+	switch (id) {
+	case PPMU_PMNCNT0:
+	case PPMU_PMNCNT1:
+	case PPMU_PMNCNT2:
+		ret = regmap_read(info->regmap, PPMU_V2_PMNCT(id), &count);
+		if (ret < 0)
+			return ret;
+		load_count = count;
+		break;
+	case PPMU_PMNCNT3:
+		ret = regmap_read(info->regmap, PPMU_V2_PMCNT3_HIGH,
+						&pmcnt_high);
+		if (ret < 0)
+			return ret;
+
+		ret = regmap_read(info->regmap, PPMU_V2_PMCNT3_LOW, &pmcnt_low);
+		if (ret < 0)
+			return ret;
+
+		load_count = ((u64)((pmcnt_high & 0xff)) << 32)+ (u64)pmcnt_low;
+		break;
+	}
+	edata->load_count = load_count;
+
+	/* Disable all counters */
+	ret = regmap_read(info->regmap, PPMU_V2_CNTENC, &cntenc);
+	if (ret < 0)
+		return 0;
+
+	cntenc |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
+	ret = regmap_write(info->regmap, PPMU_V2_CNTENC, cntenc);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&edev->dev, "%25s (load: %ld / %ld)\n", edev->desc->name,
+					edata->load_count, edata->total_count);
+	return 0;
+}
+
+static const struct devfreq_event_ops exynos_ppmu_v2_ops = {
+	.disable = exynos_ppmu_v2_disable,
+	.set_event = exynos_ppmu_v2_set_event,
+	.get_event = exynos_ppmu_v2_get_event,
+};
+
+static const struct of_device_id exynos_ppmu_id_match[] = {
+	{
+		.compatible = "samsung,exynos-ppmu",
+		.data = (void *)EXYNOS_TYPE_PPMU,
+	}, {
+		.compatible = "samsung,exynos-ppmu-v2",
+		.data = (void *)EXYNOS_TYPE_PPMU_V2,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, exynos_ppmu_id_match);
+
+static int of_get_devfreq_events(struct device_node *np,
+				 struct exynos_ppmu *info)
+{
+	struct devfreq_event_desc *desc;
+	struct device *dev = info->dev;
+	struct device_node *events_np, *node;
+	int i, j, count;
+	const struct of_device_id *of_id;
+	int ret;
+
+	events_np = of_get_child_by_name(np, "events");
+	if (!events_np) {
+		dev_err(dev,
+			"failed to get child node of devfreq-event devices\n");
+		return -EINVAL;
+	}
+
+	count = of_get_child_count(events_np);
+	desc = devm_kcalloc(dev, count, sizeof(*desc), GFP_KERNEL);
+	if (!desc) {
+		of_node_put(events_np);
+		return -ENOMEM;
+	}
+	info->num_events = count;
+
+	of_id = of_match_device(exynos_ppmu_id_match, dev);
+	if (of_id)
+		info->ppmu_type = (enum exynos_ppmu_type)of_id->data;
+	else {
+		of_node_put(events_np);
+		return -EINVAL;
+	}
+
+	j = 0;
+	for_each_child_of_node(events_np, node) {
+		for (i = 0; i < ARRAY_SIZE(ppmu_events); i++) {
+			if (!ppmu_events[i].name)
+				continue;
+
+			if (of_node_name_eq(node, ppmu_events[i].name))
+				break;
+		}
+
+		if (i == ARRAY_SIZE(ppmu_events)) {
+			dev_warn(dev,
+				"don't know how to configure events : %pOFn\n",
+				node);
+			continue;
+		}
+
+		switch (info->ppmu_type) {
+		case EXYNOS_TYPE_PPMU:
+			desc[j].ops = &exynos_ppmu_ops;
+			break;
+		case EXYNOS_TYPE_PPMU_V2:
+			desc[j].ops = &exynos_ppmu_v2_ops;
+			break;
+		}
+
+		desc[j].driver_data = info;
+
+		of_property_read_string(node, "event-name", &desc[j].name);
+		ret = of_property_read_u32(node, "event-data-type",
+					   &desc[j].event_type);
+		if (ret) {
+			/* Set the event of proper data type counting.
+			 * Check if the data type has been defined in DT,
+			 * use default if not.
+			 */
+			if (info->ppmu_type == EXYNOS_TYPE_PPMU_V2) {
+				/* Not all registers take the same value for
+				 * read+write data count.
+				 */
+				switch (ppmu_events[i].id) {
+				case PPMU_PMNCNT0:
+				case PPMU_PMNCNT1:
+				case PPMU_PMNCNT2:
+					desc[j].event_type = PPMU_V2_RO_DATA_CNT
+						| PPMU_V2_WO_DATA_CNT;
+					break;
+				case PPMU_PMNCNT3:
+					desc[j].event_type =
+						PPMU_V2_EVT3_RW_DATA_CNT;
+					break;
+				}
+			} else {
+				desc[j].event_type = PPMU_RO_DATA_CNT |
+					PPMU_WO_DATA_CNT;
+			}
+		}
+
+		j++;
+	}
+	info->desc = desc;
+
+	of_node_put(events_np);
+
+	return 0;
+}
+
+static struct regmap_config exynos_ppmu_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static int exynos_ppmu_parse_dt(struct platform_device *pdev,
+				struct exynos_ppmu *info)
+{
+	struct device *dev = info->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *res;
+	void __iomem *base;
+	int ret = 0;
+
+	if (!np) {
+		dev_err(dev, "failed to find devicetree node\n");
+		return -EINVAL;
+	}
+
+	/* Maps the memory mapped IO to control PPMU register */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	exynos_ppmu_regmap_config.max_register = resource_size(res) - 4;
+	info->regmap = devm_regmap_init_mmio(dev, base,
+					&exynos_ppmu_regmap_config);
+	if (IS_ERR(info->regmap)) {
+		dev_err(dev, "failed to initialize regmap\n");
+		return PTR_ERR(info->regmap);
+	}
+
+	info->ppmu.clk = devm_clk_get(dev, "ppmu");
+	if (IS_ERR(info->ppmu.clk)) {
+		info->ppmu.clk = NULL;
+		dev_warn(dev, "cannot get PPMU clock\n");
+	}
+
+	ret = of_get_devfreq_events(np, info);
+	if (ret < 0) {
+		dev_err(dev, "failed to parse exynos ppmu dt node\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int exynos_ppmu_probe(struct platform_device *pdev)
+{
+	struct exynos_ppmu *info;
+	struct devfreq_event_dev **edev;
+	struct devfreq_event_desc *desc;
+	int i, ret = 0, size;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->dev = &pdev->dev;
+
+	/* Parse dt data to get resource */
+	ret = exynos_ppmu_parse_dt(pdev, info);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"failed to parse devicetree for resource\n");
+		return ret;
+	}
+	desc = info->desc;
+
+	size = sizeof(struct devfreq_event_dev *) * info->num_events;
+	info->edev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+	if (!info->edev)
+		return -ENOMEM;
+
+	edev = info->edev;
+	platform_set_drvdata(pdev, info);
+
+	for (i = 0; i < info->num_events; i++) {
+		edev[i] = devm_devfreq_event_add_edev(&pdev->dev, &desc[i]);
+		if (IS_ERR(edev[i])) {
+			dev_err(&pdev->dev,
+				"failed to add devfreq-event device\n");
+			return PTR_ERR(edev[i]);
+		}
+
+		pr_info("exynos-ppmu: new PPMU device registered %s (%s)\n",
+			dev_name(&pdev->dev), desc[i].name);
+	}
+
+	ret = clk_prepare_enable(info->ppmu.clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to prepare ppmu clock\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int exynos_ppmu_remove(struct platform_device *pdev)
+{
+	struct exynos_ppmu *info = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(info->ppmu.clk);
+
+	return 0;
+}
+
+static struct platform_driver exynos_ppmu_driver = {
+	.probe	= exynos_ppmu_probe,
+	.remove	= exynos_ppmu_remove,
+	.driver = {
+		.name	= "exynos-ppmu",
+		.of_match_table = exynos_ppmu_id_match,
+	},
+};
+module_platform_driver(exynos_ppmu_driver);
+
+MODULE_DESCRIPTION("Exynos PPMU(Platform Performance Monitoring Unit) driver");
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/event/exynos-ppmu.h b/drivers/devfreq/event/exynos-ppmu.h
new file mode 100644
index 000000000..97f667d0c
--- /dev/null
+++ b/drivers/devfreq/event/exynos-ppmu.h
@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * exynos_ppmu.h - Exynos PPMU header file
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ */
+
+#ifndef __EXYNOS_PPMU_H__
+#define __EXYNOS_PPMU_H__
+
+enum ppmu_state {
+	PPMU_DISABLE = 0,
+	PPMU_ENABLE,
+};
+
+enum ppmu_counter {
+	PPMU_PMNCNT0 = 0,
+	PPMU_PMNCNT1,
+	PPMU_PMNCNT2,
+	PPMU_PMNCNT3,
+
+	PPMU_PMNCNT_MAX,
+};
+
+/***
+ * PPMUv1.1 Definitions
+ */
+enum ppmu_event_type {
+	PPMU_RO_BUSY_CYCLE_CNT	= 0x0,
+	PPMU_WO_BUSY_CYCLE_CNT	= 0x1,
+	PPMU_RW_BUSY_CYCLE_CNT	= 0x2,
+	PPMU_RO_REQUEST_CNT	= 0x3,
+	PPMU_WO_REQUEST_CNT	= 0x4,
+	PPMU_RO_DATA_CNT	= 0x5,
+	PPMU_WO_DATA_CNT	= 0x6,
+	PPMU_RO_LATENCY		= 0x12,
+	PPMU_WO_LATENCY		= 0x16,
+};
+
+enum ppmu_reg {
+	/* PPC control register */
+	PPMU_PMNC		= 0x00,
+	PPMU_CNTENS		= 0x10,
+	PPMU_CNTENC		= 0x20,
+	PPMU_INTENS		= 0x30,
+	PPMU_INTENC		= 0x40,
+	PPMU_FLAG		= 0x50,
+
+	/* Cycle Counter and Performance Event Counter Register */
+	PPMU_CCNT		= 0x100,
+	PPMU_PMCNT0		= 0x110,
+	PPMU_PMCNT1		= 0x120,
+	PPMU_PMCNT2		= 0x130,
+	PPMU_PMCNT3_HIGH	= 0x140,
+	PPMU_PMCNT3_LOW		= 0x150,
+
+	/* Bus Event Generator */
+	PPMU_BEVT0SEL		= 0x1000,
+	PPMU_BEVT1SEL		= 0x1100,
+	PPMU_BEVT2SEL		= 0x1200,
+	PPMU_BEVT3SEL		= 0x1300,
+	PPMU_COUNTER_RESET	= 0x1810,
+	PPMU_READ_OVERFLOW_CNT	= 0x1810,
+	PPMU_READ_UNDERFLOW_CNT	= 0x1814,
+	PPMU_WRITE_OVERFLOW_CNT	= 0x1850,
+	PPMU_WRITE_UNDERFLOW_CNT = 0x1854,
+	PPMU_READ_PENDING_CNT	= 0x1880,
+	PPMU_WRITE_PENDING_CNT	= 0x1884
+};
+
+/* PMNC register */
+#define PPMU_PMNC_CC_RESET_SHIFT	2
+#define PPMU_PMNC_COUNTER_RESET_SHIFT	1
+#define PPMU_PMNC_ENABLE_SHIFT		0
+#define PPMU_PMNC_START_MODE_MASK	BIT(16)
+#define PPMU_PMNC_CC_DIVIDER_MASK	BIT(3)
+#define PPMU_PMNC_CC_RESET_MASK		BIT(2)
+#define PPMU_PMNC_COUNTER_RESET_MASK	BIT(1)
+#define PPMU_PMNC_ENABLE_MASK		BIT(0)
+
+/* CNTENS/CNTENC/INTENS/INTENC/FLAG register */
+#define PPMU_CCNT_MASK			BIT(31)
+#define PPMU_PMCNT3_MASK		BIT(3)
+#define PPMU_PMCNT2_MASK		BIT(2)
+#define PPMU_PMCNT1_MASK		BIT(1)
+#define PPMU_PMCNT0_MASK		BIT(0)
+
+/* PPMU_PMNCTx/PPMU_BETxSEL registers */
+#define PPMU_PMNCT(x)			(PPMU_PMCNT0 + (0x10 * x))
+#define PPMU_BEVTxSEL(x)		(PPMU_BEVT0SEL + (0x100 * x))
+
+/***
+ * PPMU_V2.0 definitions
+ */
+enum ppmu_v2_mode {
+	PPMU_V2_MODE_MANUAL = 0,
+	PPMU_V2_MODE_AUTO = 1,
+	PPMU_V2_MODE_CIG = 2,	/* CIG (Conditional Interrupt Generation) */
+};
+
+enum ppmu_v2_event_type {
+	PPMU_V2_RO_DATA_CNT	= 0x4,
+	PPMU_V2_WO_DATA_CNT	= 0x5,
+
+	PPMU_V2_EVT3_RW_DATA_CNT = 0x22,	/* Only for Event3 */
+};
+
+enum ppmu_V2_reg {
+	/* PPC control register */
+	PPMU_V2_PMNC		= 0x04,
+	PPMU_V2_CNTENS		= 0x08,
+	PPMU_V2_CNTENC		= 0x0c,
+	PPMU_V2_INTENS		= 0x10,
+	PPMU_V2_INTENC		= 0x14,
+	PPMU_V2_FLAG		= 0x18,
+
+	/* Cycle Counter and Performance Event Counter Register */
+	PPMU_V2_CCNT		= 0x48,
+	PPMU_V2_PMCNT0		= 0x34,
+	PPMU_V2_PMCNT1		= 0x38,
+	PPMU_V2_PMCNT2		= 0x3c,
+	PPMU_V2_PMCNT3_LOW	= 0x40,
+	PPMU_V2_PMCNT3_HIGH	= 0x44,
+
+	/* Bus Event Generator */
+	PPMU_V2_CIG_CFG0		= 0x1c,
+	PPMU_V2_CIG_CFG1		= 0x20,
+	PPMU_V2_CIG_CFG2		= 0x24,
+	PPMU_V2_CIG_RESULT	= 0x28,
+	PPMU_V2_CNT_RESET	= 0x2c,
+	PPMU_V2_CNT_AUTO		= 0x30,
+	PPMU_V2_CH_EV0_TYPE	= 0x200,
+	PPMU_V2_CH_EV1_TYPE	= 0x204,
+	PPMU_V2_CH_EV2_TYPE	= 0x208,
+	PPMU_V2_CH_EV3_TYPE	= 0x20c,
+	PPMU_V2_SM_ID_V		= 0x220,
+	PPMU_V2_SM_ID_A		= 0x224,
+	PPMU_V2_SM_OTHERS_V	= 0x228,
+	PPMU_V2_SM_OTHERS_A	= 0x22c,
+	PPMU_V2_INTERRUPT_RESET	= 0x260,
+};
+
+/* PMNC register */
+#define PPMU_V2_PMNC_START_MODE_SHIFT	20
+#define PPMU_V2_PMNC_START_MODE_MASK	(0x3 << PPMU_V2_PMNC_START_MODE_SHIFT)
+
+#define PPMU_PMNC_CC_RESET_SHIFT	2
+#define PPMU_PMNC_COUNTER_RESET_SHIFT	1
+#define PPMU_PMNC_ENABLE_SHIFT		0
+#define PPMU_PMNC_START_MODE_MASK	BIT(16)
+#define PPMU_PMNC_CC_DIVIDER_MASK	BIT(3)
+#define PPMU_PMNC_CC_RESET_MASK		BIT(2)
+#define PPMU_PMNC_COUNTER_RESET_MASK	BIT(1)
+#define PPMU_PMNC_ENABLE_MASK		BIT(0)
+
+#define PPMU_V2_PMNCT(x)		(PPMU_V2_PMCNT0 + (0x4 * x))
+#define PPMU_V2_CH_EVx_TYPE(x)		(PPMU_V2_CH_EV0_TYPE + (0x4 * x))
+
+#endif /* __EXYNOS_PPMU_H__ */
diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
new file mode 100644
index 000000000..74893c06a
--- /dev/null
+++ b/drivers/devfreq/event/rockchip-dfi.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ * Author: Lin Huang <hl@rock-chips.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/of.h>
+
+#include <soc/rockchip/rk3399_grf.h>
+
+#define RK3399_DMC_NUM_CH	2
+
+/* DDRMON_CTRL */
+#define DDRMON_CTRL	0x04
+#define CLR_DDRMON_CTRL	(0x1f0000 << 0)
+#define LPDDR4_EN	(0x10001 << 4)
+#define HARDWARE_EN	(0x10001 << 3)
+#define LPDDR3_EN	(0x10001 << 2)
+#define SOFTWARE_EN	(0x10001 << 1)
+#define SOFTWARE_DIS	(0x10000 << 1)
+#define TIME_CNT_EN	(0x10001 << 0)
+
+#define DDRMON_CH0_COUNT_NUM		0x28
+#define DDRMON_CH0_DFI_ACCESS_NUM	0x2c
+#define DDRMON_CH1_COUNT_NUM		0x3c
+#define DDRMON_CH1_DFI_ACCESS_NUM	0x40
+
+struct dmc_usage {
+	u32 access;
+	u32 total;
+};
+
+/*
+ * The dfi controller can monitor DDR load. It has an upper and lower threshold
+ * for the operating points. Whenever the usage leaves these bounds an event is
+ * generated to indicate the DDR frequency should be changed.
+ */
+struct rockchip_dfi {
+	struct devfreq_event_dev *edev;
+	struct devfreq_event_desc *desc;
+	struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
+	struct device *dev;
+	void __iomem *regs;
+	struct regmap *regmap_pmu;
+	struct clk *clk;
+};
+
+static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	void __iomem *dfi_regs = info->regs;
+	u32 val;
+	u32 ddr_type;
+
+	/* get ddr type */
+	regmap_read(info->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
+	ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
+		    RK3399_PMUGRF_DDRTYPE_MASK;
+
+	/* clear DDRMON_CTRL setting */
+	writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
+
+	/* set ddr type to dfi */
+	if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR3)
+		writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
+	else if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR4)
+		writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
+
+	/* enable count, use software mode */
+	writel_relaxed(SOFTWARE_EN, dfi_regs + DDRMON_CTRL);
+}
+
+static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	void __iomem *dfi_regs = info->regs;
+
+	writel_relaxed(SOFTWARE_DIS, dfi_regs + DDRMON_CTRL);
+}
+
+static int rockchip_dfi_get_busier_ch(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	u32 tmp, max = 0;
+	u32 i, busier_ch = 0;
+	void __iomem *dfi_regs = info->regs;
+
+	rockchip_dfi_stop_hardware_counter(edev);
+
+	/* Find out which channel is busier */
+	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
+		info->ch_usage[i].access = readl_relaxed(dfi_regs +
+				DDRMON_CH0_DFI_ACCESS_NUM + i * 20) * 4;
+		info->ch_usage[i].total = readl_relaxed(dfi_regs +
+				DDRMON_CH0_COUNT_NUM + i * 20);
+		tmp = info->ch_usage[i].access;
+		if (tmp > max) {
+			busier_ch = i;
+			max = tmp;
+		}
+	}
+	rockchip_dfi_start_hardware_counter(edev);
+
+	return busier_ch;
+}
+
+static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+
+	rockchip_dfi_stop_hardware_counter(edev);
+	clk_disable_unprepare(info->clk);
+
+	return 0;
+}
+
+static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	int ret;
+
+	ret = clk_prepare_enable(info->clk);
+	if (ret) {
+		dev_err(&edev->dev, "failed to enable dfi clk: %d\n", ret);
+		return ret;
+	}
+
+	rockchip_dfi_start_hardware_counter(edev);
+	return 0;
+}
+
+static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
+{
+	return 0;
+}
+
+static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
+				  struct devfreq_event_data *edata)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	int busier_ch;
+
+	busier_ch = rockchip_dfi_get_busier_ch(edev);
+
+	edata->load_count = info->ch_usage[busier_ch].access;
+	edata->total_count = info->ch_usage[busier_ch].total;
+
+	return 0;
+}
+
+static const struct devfreq_event_ops rockchip_dfi_ops = {
+	.disable = rockchip_dfi_disable,
+	.enable = rockchip_dfi_enable,
+	.get_event = rockchip_dfi_get_event,
+	.set_event = rockchip_dfi_set_event,
+};
+
+static const struct of_device_id rockchip_dfi_id_match[] = {
+	{ .compatible = "rockchip,rk3399-dfi" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rockchip_dfi_id_match);
+
+static int rockchip_dfi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_dfi *data;
+	struct devfreq_event_desc *desc;
+	struct device_node *np = pdev->dev.of_node, *node;
+
+	data = devm_kzalloc(dev, sizeof(struct rockchip_dfi), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->regs))
+		return PTR_ERR(data->regs);
+
+	data->clk = devm_clk_get(dev, "pclk_ddr_mon");
+	if (IS_ERR(data->clk))
+		return dev_err_probe(dev, PTR_ERR(data->clk),
+				     "Cannot get the clk pclk_ddr_mon\n");
+
+	node = of_parse_phandle(np, "rockchip,pmu", 0);
+	if (!node)
+		return dev_err_probe(&pdev->dev, -ENODEV, "Can't find pmu_grf registers\n");
+
+	data->regmap_pmu = syscon_node_to_regmap(node);
+	of_node_put(node);
+	if (IS_ERR(data->regmap_pmu))
+		return PTR_ERR(data->regmap_pmu);
+
+	data->dev = dev;
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	desc->ops = &rockchip_dfi_ops;
+	desc->driver_data = data;
+	desc->name = np->name;
+	data->desc = desc;
+
+	data->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
+	if (IS_ERR(data->edev)) {
+		dev_err(&pdev->dev,
+			"failed to add devfreq-event device\n");
+		return PTR_ERR(data->edev);
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static struct platform_driver rockchip_dfi_driver = {
+	.probe	= rockchip_dfi_probe,
+	.driver = {
+		.name	= "rockchip-dfi",
+		.of_match_table = rockchip_dfi_id_match,
+	},
+};
+module_platform_driver(rockchip_dfi_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
+MODULE_DESCRIPTION("Rockchip DFI driver");
diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
new file mode 100644
index 000000000..027e8f336
--- /dev/null
+++ b/drivers/devfreq/exynos-bus.c
@@ -0,0 +1,523 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic Exynos Bus frequency driver with DEVFREQ Framework
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This driver support Exynos Bus frequency feature by using
+ * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
+ */
+
+#include <linux/clk.h>
+#include <linux/devfreq.h>
+#include <linux/devfreq-event.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define DEFAULT_SATURATION_RATIO	40
+
+struct exynos_bus {
+	struct device *dev;
+	struct platform_device *icc_pdev;
+
+	struct devfreq *devfreq;
+	struct devfreq_event_dev **edev;
+	unsigned int edev_count;
+	struct mutex lock;
+
+	unsigned long curr_freq;
+
+	int opp_token;
+	struct clk *clk;
+	unsigned int ratio;
+};
+
+/*
+ * Control the devfreq-event device to get the current state of bus
+ */
+#define exynos_bus_ops_edev(ops)				\
+static int exynos_bus_##ops(struct exynos_bus *bus)		\
+{								\
+	int i, ret;						\
+								\
+	for (i = 0; i < bus->edev_count; i++) {			\
+		if (!bus->edev[i])				\
+			continue;				\
+		ret = devfreq_event_##ops(bus->edev[i]);	\
+		if (ret < 0)					\
+			return ret;				\
+	}							\
+								\
+	return 0;						\
+}
+exynos_bus_ops_edev(enable_edev);
+exynos_bus_ops_edev(disable_edev);
+exynos_bus_ops_edev(set_event);
+
+static int exynos_bus_get_event(struct exynos_bus *bus,
+				struct devfreq_event_data *edata)
+{
+	struct devfreq_event_data event_data;
+	unsigned long load_count = 0, total_count = 0;
+	int i, ret = 0;
+
+	for (i = 0; i < bus->edev_count; i++) {
+		if (!bus->edev[i])
+			continue;
+
+		ret = devfreq_event_get_event(bus->edev[i], &event_data);
+		if (ret < 0)
+			return ret;
+
+		if (i == 0 || event_data.load_count > load_count) {
+			load_count = event_data.load_count;
+			total_count = event_data.total_count;
+		}
+	}
+
+	edata->load_count = load_count;
+	edata->total_count = total_count;
+
+	return ret;
+}
+
+/*
+ * devfreq function for both simple-ondemand and passive governor
+ */
+static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+	struct dev_pm_opp *new_opp;
+	int ret = 0;
+
+	/* Get correct frequency for bus. */
+	new_opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(new_opp)) {
+		dev_err(dev, "failed to get recommended opp instance\n");
+		return PTR_ERR(new_opp);
+	}
+
+	dev_pm_opp_put(new_opp);
+
+	/* Change voltage and frequency according to new OPP level */
+	mutex_lock(&bus->lock);
+	ret = dev_pm_opp_set_rate(dev, *freq);
+	if (!ret)
+		bus->curr_freq = *freq;
+
+	mutex_unlock(&bus->lock);
+
+	return ret;
+}
+
+static int exynos_bus_get_dev_status(struct device *dev,
+				     struct devfreq_dev_status *stat)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+	struct devfreq_event_data edata;
+	int ret;
+
+	stat->current_frequency = bus->curr_freq;
+
+	ret = exynos_bus_get_event(bus, &edata);
+	if (ret < 0) {
+		dev_err(dev, "failed to get event from devfreq-event devices\n");
+		stat->total_time = stat->busy_time = 0;
+		goto err;
+	}
+
+	stat->busy_time = (edata.load_count * 100) / bus->ratio;
+	stat->total_time = edata.total_count;
+
+	dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
+							stat->total_time);
+
+err:
+	ret = exynos_bus_set_event(bus);
+	if (ret < 0) {
+		dev_err(dev, "failed to set event to devfreq-event devices\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static void exynos_bus_exit(struct device *dev)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+	int ret;
+
+	ret = exynos_bus_disable_edev(bus);
+	if (ret < 0)
+		dev_warn(dev, "failed to disable the devfreq-event devices\n");
+
+	platform_device_unregister(bus->icc_pdev);
+
+	dev_pm_opp_of_remove_table(dev);
+	clk_disable_unprepare(bus->clk);
+	dev_pm_opp_put_regulators(bus->opp_token);
+}
+
+static void exynos_bus_passive_exit(struct device *dev)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+
+	platform_device_unregister(bus->icc_pdev);
+
+	dev_pm_opp_of_remove_table(dev);
+	clk_disable_unprepare(bus->clk);
+}
+
+static int exynos_bus_parent_parse_of(struct device_node *np,
+					struct exynos_bus *bus)
+{
+	struct device *dev = bus->dev;
+	const char *supplies[] = { "vdd", NULL };
+	int i, ret, count, size;
+
+	ret = dev_pm_opp_set_regulators(dev, supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to set regulators %d\n", ret);
+		return ret;
+	}
+
+	bus->opp_token = ret;
+
+	/*
+	 * Get the devfreq-event devices to get the current utilization of
+	 * buses. This raw data will be used in devfreq ondemand governor.
+	 */
+	count = devfreq_event_get_edev_count(dev, "devfreq-events");
+	if (count < 0) {
+		dev_err(dev, "failed to get the count of devfreq-event dev\n");
+		ret = count;
+		goto err_regulator;
+	}
+	bus->edev_count = count;
+
+	size = sizeof(*bus->edev) * count;
+	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
+	if (!bus->edev) {
+		ret = -ENOMEM;
+		goto err_regulator;
+	}
+
+	for (i = 0; i < count; i++) {
+		bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
+							"devfreq-events", i);
+		if (IS_ERR(bus->edev[i])) {
+			ret = -EPROBE_DEFER;
+			goto err_regulator;
+		}
+	}
+
+	/*
+	 * Optionally, Get the saturation ratio according to Exynos SoC
+	 * When measuring the utilization of each AXI bus with devfreq-event
+	 * devices, the measured real cycle might be much lower than the
+	 * total cycle of bus during sampling rate. In result, the devfreq
+	 * simple-ondemand governor might not decide to change the current
+	 * frequency due to too utilization (= real cycle/total cycle).
+	 * So, this property is used to adjust the utilization when calculating
+	 * the busy_time in exynos_bus_get_dev_status().
+	 */
+	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
+		bus->ratio = DEFAULT_SATURATION_RATIO;
+
+	return 0;
+
+err_regulator:
+	dev_pm_opp_put_regulators(bus->opp_token);
+
+	return ret;
+}
+
+static int exynos_bus_parse_of(struct device_node *np,
+			      struct exynos_bus *bus)
+{
+	struct device *dev = bus->dev;
+	struct dev_pm_opp *opp;
+	unsigned long rate;
+	int ret;
+
+	/* Get the clock to provide each bus with source clock */
+	bus->clk = devm_clk_get(dev, "bus");
+	if (IS_ERR(bus->clk)) {
+		dev_err(dev, "failed to get bus clock\n");
+		return PTR_ERR(bus->clk);
+	}
+
+	ret = clk_prepare_enable(bus->clk);
+	if (ret < 0) {
+		dev_err(dev, "failed to get enable clock\n");
+		return ret;
+	}
+
+	/* Get the freq and voltage from OPP table to scale the bus freq */
+	ret = dev_pm_opp_of_add_table(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to get OPP table\n");
+		goto err_clk;
+	}
+
+	rate = clk_get_rate(bus->clk);
+
+	opp = devfreq_recommended_opp(dev, &rate, 0);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "failed to find dev_pm_opp\n");
+		ret = PTR_ERR(opp);
+		goto err_opp;
+	}
+	bus->curr_freq = dev_pm_opp_get_freq(opp);
+	dev_pm_opp_put(opp);
+
+	return 0;
+
+err_opp:
+	dev_pm_opp_of_remove_table(dev);
+err_clk:
+	clk_disable_unprepare(bus->clk);
+
+	return ret;
+}
+
+static int exynos_bus_profile_init(struct exynos_bus *bus,
+				   struct devfreq_dev_profile *profile)
+{
+	struct device *dev = bus->dev;
+	struct devfreq_simple_ondemand_data *ondemand_data;
+	int ret;
+
+	/* Initialize the struct profile and governor data for parent device */
+	profile->polling_ms = 50;
+	profile->target = exynos_bus_target;
+	profile->get_dev_status = exynos_bus_get_dev_status;
+	profile->exit = exynos_bus_exit;
+
+	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
+	if (!ondemand_data)
+		return -ENOMEM;
+
+	ondemand_data->upthreshold = 40;
+	ondemand_data->downdifferential = 5;
+
+	/* Add devfreq device to monitor and handle the exynos bus */
+	bus->devfreq = devm_devfreq_add_device(dev, profile,
+						DEVFREQ_GOV_SIMPLE_ONDEMAND,
+						ondemand_data);
+	if (IS_ERR(bus->devfreq)) {
+		dev_err(dev, "failed to add devfreq device\n");
+		return PTR_ERR(bus->devfreq);
+	}
+
+	/* Register opp_notifier to catch the change of OPP  */
+	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
+	if (ret < 0) {
+		dev_err(dev, "failed to register opp notifier\n");
+		return ret;
+	}
+
+	/*
+	 * Enable devfreq-event to get raw data which is used to determine
+	 * current bus load.
+	 */
+	ret = exynos_bus_enable_edev(bus);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable devfreq-event devices\n");
+		return ret;
+	}
+
+	ret = exynos_bus_set_event(bus);
+	if (ret < 0) {
+		dev_err(dev, "failed to set event to devfreq-event devices\n");
+		goto err_edev;
+	}
+
+	return 0;
+
+err_edev:
+	if (exynos_bus_disable_edev(bus))
+		dev_warn(dev, "failed to disable the devfreq-event devices\n");
+
+	return ret;
+}
+
+static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
+					   struct devfreq_dev_profile *profile)
+{
+	struct device *dev = bus->dev;
+	struct devfreq_passive_data *passive_data;
+	struct devfreq *parent_devfreq;
+
+	/* Initialize the struct profile and governor data for passive device */
+	profile->target = exynos_bus_target;
+	profile->exit = exynos_bus_passive_exit;
+
+	/* Get the instance of parent devfreq device */
+	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
+	if (IS_ERR(parent_devfreq))
+		return -EPROBE_DEFER;
+
+	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
+	if (!passive_data)
+		return -ENOMEM;
+
+	passive_data->parent = parent_devfreq;
+
+	/* Add devfreq device for exynos bus with passive governor */
+	bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
+						passive_data);
+	if (IS_ERR(bus->devfreq)) {
+		dev_err(dev,
+			"failed to add devfreq dev with passive governor\n");
+		return PTR_ERR(bus->devfreq);
+	}
+
+	return 0;
+}
+
+static int exynos_bus_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node, *node;
+	struct devfreq_dev_profile *profile;
+	struct exynos_bus *bus;
+	int ret, max_state;
+	unsigned long min_freq, max_freq;
+	bool passive = false;
+
+	if (!np) {
+		dev_err(dev, "failed to find devicetree node\n");
+		return -EINVAL;
+	}
+
+	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return -ENOMEM;
+	mutex_init(&bus->lock);
+	bus->dev = &pdev->dev;
+	platform_set_drvdata(pdev, bus);
+
+	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
+	if (!profile)
+		return -ENOMEM;
+
+	node = of_parse_phandle(dev->of_node, "devfreq", 0);
+	if (node) {
+		of_node_put(node);
+		passive = true;
+	} else {
+		ret = exynos_bus_parent_parse_of(np, bus);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Parse the device-tree to get the resource information */
+	ret = exynos_bus_parse_of(np, bus);
+	if (ret < 0)
+		goto err_reg;
+
+	if (passive)
+		ret = exynos_bus_profile_init_passive(bus, profile);
+	else
+		ret = exynos_bus_profile_init(bus, profile);
+
+	if (ret < 0)
+		goto err;
+
+	/* Create child platform device for the interconnect provider */
+	if (of_get_property(dev->of_node, "#interconnect-cells", NULL)) {
+		bus->icc_pdev = platform_device_register_data(
+						dev, "exynos-generic-icc",
+						PLATFORM_DEVID_AUTO, NULL, 0);
+
+		if (IS_ERR(bus->icc_pdev)) {
+			ret = PTR_ERR(bus->icc_pdev);
+			goto err;
+		}
+	}
+
+	max_state = bus->devfreq->max_state;
+	min_freq = (bus->devfreq->freq_table[0] / 1000);
+	max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
+	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
+			dev_name(dev), min_freq, max_freq);
+
+	return 0;
+
+err:
+	dev_pm_opp_of_remove_table(dev);
+	clk_disable_unprepare(bus->clk);
+err_reg:
+	dev_pm_opp_put_regulators(bus->opp_token);
+
+	return ret;
+}
+
+static void exynos_bus_shutdown(struct platform_device *pdev)
+{
+	struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
+
+	devfreq_suspend_device(bus->devfreq);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int exynos_bus_resume(struct device *dev)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+	int ret;
+
+	ret = exynos_bus_enable_edev(bus);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable the devfreq-event devices\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int exynos_bus_suspend(struct device *dev)
+{
+	struct exynos_bus *bus = dev_get_drvdata(dev);
+	int ret;
+
+	ret = exynos_bus_disable_edev(bus);
+	if (ret < 0) {
+		dev_err(dev, "failed to disable the devfreq-event devices\n");
+		return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops exynos_bus_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
+};
+
+static const struct of_device_id exynos_bus_of_match[] = {
+	{ .compatible = "samsung,exynos-bus", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
+
+static struct platform_driver exynos_bus_platdrv = {
+	.probe		= exynos_bus_probe,
+	.shutdown	= exynos_bus_shutdown,
+	.driver = {
+		.name	= "exynos-bus",
+		.pm	= &exynos_bus_pm,
+		.of_match_table = of_match_ptr(exynos_bus_of_match),
+	},
+};
+module_platform_driver(exynos_bus_platdrv);
+
+MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
new file mode 100644
index 000000000..0adfebc04
--- /dev/null
+++ b/drivers/devfreq/governor.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * governor.h - internal header for devfreq governors.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This header is for devfreq governors in drivers/devfreq/
+ */
+
+#ifndef _GOVERNOR_H
+#define _GOVERNOR_H
+
+#include <linux/devfreq.h>
+
+#define DEVFREQ_NAME_LEN			16
+
+#define to_devfreq(DEV)	container_of((DEV), struct devfreq, dev)
+
+/* Devfreq events */
+#define DEVFREQ_GOV_START			0x1
+#define DEVFREQ_GOV_STOP			0x2
+#define DEVFREQ_GOV_UPDATE_INTERVAL		0x3
+#define DEVFREQ_GOV_SUSPEND			0x4
+#define DEVFREQ_GOV_RESUME			0x5
+
+#define DEVFREQ_MIN_FREQ			0
+#define DEVFREQ_MAX_FREQ			ULONG_MAX
+
+/*
+ * Definition of the governor feature flags
+ * - DEVFREQ_GOV_FLAG_IMMUTABLE
+ *   : This governor is never changeable to other governors.
+ * - DEVFREQ_GOV_FLAG_IRQ_DRIVEN
+ *   : The devfreq won't schedule the work for this governor.
+ */
+#define DEVFREQ_GOV_FLAG_IMMUTABLE			BIT(0)
+#define DEVFREQ_GOV_FLAG_IRQ_DRIVEN			BIT(1)
+
+/*
+ * Definition of governor attribute flags except for common sysfs attributes
+ * - DEVFREQ_GOV_ATTR_POLLING_INTERVAL
+ *   : Indicate polling_interval sysfs attribute
+ * - DEVFREQ_GOV_ATTR_TIMER
+ *   : Indicate timer sysfs attribute
+ */
+#define DEVFREQ_GOV_ATTR_POLLING_INTERVAL		BIT(0)
+#define DEVFREQ_GOV_ATTR_TIMER				BIT(1)
+
+/**
+ * struct devfreq_cpu_data - Hold the per-cpu data
+ * @node:	list node
+ * @dev:	reference to cpu device.
+ * @first_cpu:	the cpumask of the first cpu of a policy.
+ * @opp_table:	reference to cpu opp table.
+ * @cur_freq:	the current frequency of the cpu.
+ * @min_freq:	the min frequency of the cpu.
+ * @max_freq:	the max frequency of the cpu.
+ *
+ * This structure stores the required cpu_data of a cpu.
+ * This is auto-populated by the governor.
+ */
+struct devfreq_cpu_data {
+	struct list_head node;
+
+	struct device *dev;
+	unsigned int first_cpu;
+
+	struct opp_table *opp_table;
+	unsigned int cur_freq;
+	unsigned int min_freq;
+	unsigned int max_freq;
+};
+
+/**
+ * struct devfreq_governor - Devfreq policy governor
+ * @node:		list node - contains registered devfreq governors
+ * @name:		Governor's name
+ * @attrs:		Governor's sysfs attribute flags
+ * @flags:		Governor's feature flags
+ * @get_target_freq:	Returns desired operating frequency for the device.
+ *			Basically, get_target_freq will run
+ *			devfreq_dev_profile.get_dev_status() to get the
+ *			status of the device (load = busy_time / total_time).
+ * @event_handler:      Callback for devfreq core framework to notify events
+ *                      to governors. Events include per device governor
+ *                      init and exit, opp changes out of devfreq, suspend
+ *                      and resume of per device devfreq during device idle.
+ *
+ * Note that the callbacks are called with devfreq->lock locked by devfreq.
+ */
+struct devfreq_governor {
+	struct list_head node;
+
+	const char name[DEVFREQ_NAME_LEN];
+	const u64 attrs;
+	const u64 flags;
+	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
+	int (*event_handler)(struct devfreq *devfreq,
+				unsigned int event, void *data);
+};
+
+void devfreq_monitor_start(struct devfreq *devfreq);
+void devfreq_monitor_stop(struct devfreq *devfreq);
+void devfreq_monitor_suspend(struct devfreq *devfreq);
+void devfreq_monitor_resume(struct devfreq *devfreq);
+void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay);
+
+int devfreq_add_governor(struct devfreq_governor *governor);
+int devfreq_remove_governor(struct devfreq_governor *governor);
+
+int devm_devfreq_add_governor(struct device *dev,
+			      struct devfreq_governor *governor);
+
+int devfreq_update_status(struct devfreq *devfreq, unsigned long freq);
+int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
+void devfreq_get_freq_range(struct devfreq *devfreq, unsigned long *min_freq,
+			    unsigned long *max_freq);
+
+static inline int devfreq_update_stats(struct devfreq *df)
+{
+	if (!df->profile->get_dev_status)
+		return -EINVAL;
+
+	return df->profile->get_dev_status(df->dev.parent, &df->last_status);
+}
+#endif /* _GOVERNOR_H */
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
new file mode 100644
index 000000000..953cf9a1e
--- /dev/null
+++ b/drivers/devfreq/governor_passive.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/drivers/devfreq/governor_passive.c
+ *
+ * Copyright (C) 2016 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/devfreq.h>
+#include <linux/units.h>
+#include "governor.h"
+
+static struct devfreq_cpu_data *
+get_parent_cpu_data(struct devfreq_passive_data *p_data,
+		    struct cpufreq_policy *policy)
+{
+	struct devfreq_cpu_data *parent_cpu_data;
+
+	if (!p_data || !policy)
+		return NULL;
+
+	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node)
+		if (parent_cpu_data->first_cpu == cpumask_first(policy->related_cpus))
+			return parent_cpu_data;
+
+	return NULL;
+}
+
+static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
+{
+	struct devfreq_cpu_data *parent_cpu_data, *tmp;
+
+	list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+		list_del(&parent_cpu_data->node);
+
+		if (parent_cpu_data->opp_table)
+			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+		kfree(parent_cpu_data);
+	}
+}
+
+static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
+						struct opp_table *p_opp_table,
+						struct opp_table *opp_table,
+						unsigned long *freq)
+{
+	struct dev_pm_opp *opp = NULL, *p_opp = NULL;
+	unsigned long target_freq;
+
+	if (!p_dev || !p_opp_table || !opp_table || !freq)
+		return 0;
+
+	p_opp = devfreq_recommended_opp(p_dev, freq, 0);
+	if (IS_ERR(p_opp))
+		return 0;
+
+	opp = dev_pm_opp_xlate_required_opp(p_opp_table, opp_table, p_opp);
+	dev_pm_opp_put(p_opp);
+
+	if (IS_ERR(opp))
+		return 0;
+
+	target_freq = dev_pm_opp_get_freq(opp);
+	dev_pm_opp_put(opp);
+
+	return target_freq;
+}
+
+static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
+					unsigned long *target_freq)
+{
+	struct devfreq_passive_data *p_data =
+				(struct devfreq_passive_data *)devfreq->data;
+	struct devfreq_cpu_data *parent_cpu_data;
+	struct cpufreq_policy *policy;
+	unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
+	unsigned long dev_min, dev_max;
+	unsigned long freq = 0;
+	int ret = 0;
+
+	for_each_online_cpu(cpu) {
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy) {
+			ret = -EINVAL;
+			continue;
+		}
+
+		parent_cpu_data = get_parent_cpu_data(p_data, policy);
+		if (!parent_cpu_data) {
+			cpufreq_cpu_put(policy);
+			continue;
+		}
+
+		/* Get target freq via required opps */
+		cpu_cur = parent_cpu_data->cur_freq * HZ_PER_KHZ;
+		freq = get_target_freq_by_required_opp(parent_cpu_data->dev,
+					parent_cpu_data->opp_table,
+					devfreq->opp_table, &cpu_cur);
+		if (freq) {
+			*target_freq = max(freq, *target_freq);
+			cpufreq_cpu_put(policy);
+			continue;
+		}
+
+		/* Use interpolation if required opps is not available */
+		devfreq_get_freq_range(devfreq, &dev_min, &dev_max);
+
+		cpu_min = parent_cpu_data->min_freq;
+		cpu_max = parent_cpu_data->max_freq;
+		cpu_cur = parent_cpu_data->cur_freq;
+
+		cpu_percent = ((cpu_cur - cpu_min) * 100) / (cpu_max - cpu_min);
+		freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
+
+		*target_freq = max(freq, *target_freq);
+		cpufreq_cpu_put(policy);
+	}
+
+	return ret;
+}
+
+static int get_target_freq_with_devfreq(struct devfreq *devfreq,
+					unsigned long *freq)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
+	unsigned long child_freq = ULONG_MAX;
+	int i, count;
+
+	/* Get target freq via required opps */
+	child_freq = get_target_freq_by_required_opp(parent_devfreq->dev.parent,
+						parent_devfreq->opp_table,
+						devfreq->opp_table, freq);
+	if (child_freq)
+		goto out;
+
+	/* Use interpolation if required opps is not available */
+	for (i = 0; i < parent_devfreq->max_state; i++)
+		if (parent_devfreq->freq_table[i] == *freq)
+			break;
+
+	if (i == parent_devfreq->max_state)
+		return -EINVAL;
+
+	if (i < devfreq->max_state) {
+		child_freq = devfreq->freq_table[i];
+	} else {
+		count = devfreq->max_state;
+		child_freq = devfreq->freq_table[count - 1];
+	}
+
+out:
+	*freq = child_freq;
+
+	return 0;
+}
+
+static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
+					   unsigned long *freq)
+{
+	struct devfreq_passive_data *p_data =
+				(struct devfreq_passive_data *)devfreq->data;
+	int ret;
+
+	if (!p_data)
+		return -EINVAL;
+
+	/*
+	 * If the devfreq device with passive governor has the specific method
+	 * to determine the next frequency, should use the get_target_freq()
+	 * of struct devfreq_passive_data.
+	 */
+	if (p_data->get_target_freq)
+		return p_data->get_target_freq(devfreq, freq);
+
+	switch (p_data->parent_type) {
+	case DEVFREQ_PARENT_DEV:
+		ret = get_target_freq_with_devfreq(devfreq, freq);
+		break;
+	case CPUFREQ_PARENT_DEV:
+		ret = get_target_freq_with_cpufreq(devfreq, freq);
+		break;
+	default:
+		ret = -EINVAL;
+		dev_err(&devfreq->dev, "Invalid parent type\n");
+		break;
+	}
+
+	return ret;
+}
+
+static int cpufreq_passive_notifier_call(struct notifier_block *nb,
+					 unsigned long event, void *ptr)
+{
+	struct devfreq_passive_data *p_data =
+			container_of(nb, struct devfreq_passive_data, nb);
+	struct devfreq *devfreq = (struct devfreq *)p_data->this;
+	struct devfreq_cpu_data *parent_cpu_data;
+	struct cpufreq_freqs *freqs = ptr;
+	unsigned int cur_freq;
+	int ret;
+
+	if (event != CPUFREQ_POSTCHANGE || !freqs)
+		return 0;
+
+	parent_cpu_data = get_parent_cpu_data(p_data, freqs->policy);
+	if (!parent_cpu_data || parent_cpu_data->cur_freq == freqs->new)
+		return 0;
+
+	cur_freq = parent_cpu_data->cur_freq;
+	parent_cpu_data->cur_freq = freqs->new;
+
+	mutex_lock(&devfreq->lock);
+	ret = devfreq_update_target(devfreq, freqs->new);
+	mutex_unlock(&devfreq->lock);
+	if (ret) {
+		parent_cpu_data->cur_freq = cur_freq;
+		dev_err(&devfreq->dev, "failed to update the frequency.\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	int ret;
+
+	if (p_data->nb.notifier_call) {
+		ret = cpufreq_unregister_notifier(&p_data->nb,
+					CPUFREQ_TRANSITION_NOTIFIER);
+		if (ret < 0)
+			return ret;
+	}
+
+	delete_parent_cpu_data(p_data);
+
+	return 0;
+}
+
+static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	struct device *dev = devfreq->dev.parent;
+	struct opp_table *opp_table = NULL;
+	struct devfreq_cpu_data *parent_cpu_data;
+	struct cpufreq_policy *policy;
+	struct device *cpu_dev;
+	unsigned int cpu;
+	int ret;
+
+	p_data->cpu_data_list
+		= (struct list_head)LIST_HEAD_INIT(p_data->cpu_data_list);
+
+	p_data->nb.notifier_call = cpufreq_passive_notifier_call;
+	ret = cpufreq_register_notifier(&p_data->nb, CPUFREQ_TRANSITION_NOTIFIER);
+	if (ret) {
+		dev_err(dev, "failed to register cpufreq notifier\n");
+		p_data->nb.notifier_call = NULL;
+		goto err;
+	}
+
+	for_each_possible_cpu(cpu) {
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy) {
+			ret = -EPROBE_DEFER;
+			goto err;
+		}
+
+		parent_cpu_data = get_parent_cpu_data(p_data, policy);
+		if (parent_cpu_data) {
+			cpufreq_cpu_put(policy);
+			continue;
+		}
+
+		parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
+						GFP_KERNEL);
+		if (!parent_cpu_data) {
+			ret = -ENOMEM;
+			goto err_put_policy;
+		}
+
+		cpu_dev = get_cpu_device(cpu);
+		if (!cpu_dev) {
+			dev_err(dev, "failed to get cpu device\n");
+			ret = -ENODEV;
+			goto err_free_cpu_data;
+		}
+
+		opp_table = dev_pm_opp_get_opp_table(cpu_dev);
+		if (IS_ERR(opp_table)) {
+			dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
+			ret = PTR_ERR(opp_table);
+			goto err_free_cpu_data;
+		}
+
+		parent_cpu_data->dev = cpu_dev;
+		parent_cpu_data->opp_table = opp_table;
+		parent_cpu_data->first_cpu = cpumask_first(policy->related_cpus);
+		parent_cpu_data->cur_freq = policy->cur;
+		parent_cpu_data->min_freq = policy->cpuinfo.min_freq;
+		parent_cpu_data->max_freq = policy->cpuinfo.max_freq;
+
+		list_add_tail(&parent_cpu_data->node, &p_data->cpu_data_list);
+		cpufreq_cpu_put(policy);
+	}
+
+	mutex_lock(&devfreq->lock);
+	ret = devfreq_update_target(devfreq, 0L);
+	mutex_unlock(&devfreq->lock);
+	if (ret)
+		dev_err(dev, "failed to update the frequency\n");
+
+	return ret;
+
+err_free_cpu_data:
+	kfree(parent_cpu_data);
+err_put_policy:
+	cpufreq_cpu_put(policy);
+err:
+
+	return ret;
+}
+
+static int devfreq_passive_notifier_call(struct notifier_block *nb,
+				unsigned long event, void *ptr)
+{
+	struct devfreq_passive_data *data
+			= container_of(nb, struct devfreq_passive_data, nb);
+	struct devfreq *devfreq = (struct devfreq *)data->this;
+	struct devfreq *parent = (struct devfreq *)data->parent;
+	struct devfreq_freqs *freqs = (struct devfreq_freqs *)ptr;
+	unsigned long freq = freqs->new;
+	int ret = 0;
+
+	mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
+	switch (event) {
+	case DEVFREQ_PRECHANGE:
+		if (parent->previous_freq > freq)
+			ret = devfreq_update_target(devfreq, freq);
+
+		break;
+	case DEVFREQ_POSTCHANGE:
+		if (parent->previous_freq < freq)
+			ret = devfreq_update_target(devfreq, freq);
+		break;
+	}
+	mutex_unlock(&devfreq->lock);
+
+	if (ret < 0)
+		dev_warn(&devfreq->dev,
+			"failed to update devfreq using passive governor\n");
+
+	return NOTIFY_DONE;
+}
+
+static int devfreq_passive_unregister_notifier(struct devfreq *devfreq)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	struct devfreq *parent = (struct devfreq *)p_data->parent;
+	struct notifier_block *nb = &p_data->nb;
+
+	return devfreq_unregister_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
+}
+
+static int devfreq_passive_register_notifier(struct devfreq *devfreq)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	struct devfreq *parent = (struct devfreq *)p_data->parent;
+	struct notifier_block *nb = &p_data->nb;
+
+	if (!parent)
+		return -EPROBE_DEFER;
+
+	nb->notifier_call = devfreq_passive_notifier_call;
+	return devfreq_register_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
+}
+
+static int devfreq_passive_event_handler(struct devfreq *devfreq,
+				unsigned int event, void *data)
+{
+	struct devfreq_passive_data *p_data
+			= (struct devfreq_passive_data *)devfreq->data;
+	int ret = 0;
+
+	if (!p_data)
+		return -EINVAL;
+
+	p_data->this = devfreq;
+
+	switch (event) {
+	case DEVFREQ_GOV_START:
+		if (p_data->parent_type == DEVFREQ_PARENT_DEV)
+			ret = devfreq_passive_register_notifier(devfreq);
+		else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
+			ret = cpufreq_passive_register_notifier(devfreq);
+		break;
+	case DEVFREQ_GOV_STOP:
+		if (p_data->parent_type == DEVFREQ_PARENT_DEV)
+			WARN_ON(devfreq_passive_unregister_notifier(devfreq));
+		else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
+			WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor devfreq_passive = {
+	.name = DEVFREQ_GOV_PASSIVE,
+	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
+	.get_target_freq = devfreq_passive_get_target_freq,
+	.event_handler = devfreq_passive_event_handler,
+};
+
+static int __init devfreq_passive_init(void)
+{
+	return devfreq_add_governor(&devfreq_passive);
+}
+subsys_initcall(devfreq_passive_init);
+
+static void __exit devfreq_passive_exit(void)
+{
+	int ret;
+
+	ret = devfreq_remove_governor(&devfreq_passive);
+	if (ret)
+		pr_err("%s: failed remove governor %d\n", __func__, ret);
+}
+module_exit(devfreq_passive_exit);
+
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_DESCRIPTION("DEVFREQ Passive governor");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
new file mode 100644
index 000000000..5dbc1e56e
--- /dev/null
+++ b/drivers/devfreq/governor_performance.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/devfreq/governor_performance.c
+ *
+ *  Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/devfreq.h>
+#include <linux/module.h>
+#include "governor.h"
+
+static int devfreq_performance_func(struct devfreq *df,
+				    unsigned long *freq)
+{
+	/*
+	 * target callback should be able to get floor value as
+	 * said in devfreq.h
+	 */
+	*freq = DEVFREQ_MAX_FREQ;
+	return 0;
+}
+
+static int devfreq_performance_handler(struct devfreq *devfreq,
+				unsigned int event, void *data)
+{
+	int ret = 0;
+
+	if (event == DEVFREQ_GOV_START) {
+		mutex_lock(&devfreq->lock);
+		ret = update_devfreq(devfreq);
+		mutex_unlock(&devfreq->lock);
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor devfreq_performance = {
+	.name = DEVFREQ_GOV_PERFORMANCE,
+	.get_target_freq = devfreq_performance_func,
+	.event_handler = devfreq_performance_handler,
+};
+
+static int __init devfreq_performance_init(void)
+{
+	return devfreq_add_governor(&devfreq_performance);
+}
+subsys_initcall(devfreq_performance_init);
+
+static void __exit devfreq_performance_exit(void)
+{
+	int ret;
+
+	ret = devfreq_remove_governor(&devfreq_performance);
+	if (ret)
+		pr_err("%s: failed remove governor %d\n", __func__, ret);
+
+	return;
+}
+module_exit(devfreq_performance_exit);
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c
new file mode 100644
index 000000000..4746af243
--- /dev/null
+++ b/drivers/devfreq/governor_powersave.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/devfreq/governor_powersave.c
+ *
+ *  Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/devfreq.h>
+#include <linux/module.h>
+#include "governor.h"
+
+static int devfreq_powersave_func(struct devfreq *df,
+				  unsigned long *freq)
+{
+	/*
+	 * target callback should be able to get ceiling value as
+	 * said in devfreq.h
+	 */
+	*freq = DEVFREQ_MIN_FREQ;
+	return 0;
+}
+
+static int devfreq_powersave_handler(struct devfreq *devfreq,
+				unsigned int event, void *data)
+{
+	int ret = 0;
+
+	if (event == DEVFREQ_GOV_START) {
+		mutex_lock(&devfreq->lock);
+		ret = update_devfreq(devfreq);
+		mutex_unlock(&devfreq->lock);
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor devfreq_powersave = {
+	.name = DEVFREQ_GOV_POWERSAVE,
+	.get_target_freq = devfreq_powersave_func,
+	.event_handler = devfreq_powersave_handler,
+};
+
+static int __init devfreq_powersave_init(void)
+{
+	return devfreq_add_governor(&devfreq_powersave);
+}
+subsys_initcall(devfreq_powersave_init);
+
+static void __exit devfreq_powersave_exit(void)
+{
+	int ret;
+
+	ret = devfreq_remove_governor(&devfreq_powersave);
+	if (ret)
+		pr_err("%s: failed remove governor %d\n", __func__, ret);
+
+	return;
+}
+module_exit(devfreq_powersave_exit);
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
new file mode 100644
index 000000000..d57b82a2b
--- /dev/null
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/devfreq/governor_simpleondemand.c
+ *
+ *  Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/devfreq.h>
+#include <linux/math64.h>
+#include "governor.h"
+
+/* Default constants for DevFreq-Simple-Ondemand (DFSO) */
+#define DFSO_UPTHRESHOLD	(90)
+#define DFSO_DOWNDIFFERENCTIAL	(5)
+static int devfreq_simple_ondemand_func(struct devfreq *df,
+					unsigned long *freq)
+{
+	int err;
+	struct devfreq_dev_status *stat;
+	unsigned long long a, b;
+	unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
+	unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
+	struct devfreq_simple_ondemand_data *data = df->data;
+
+	err = devfreq_update_stats(df);
+	if (err)
+		return err;
+
+	stat = &df->last_status;
+
+	if (data) {
+		if (data->upthreshold)
+			dfso_upthreshold = data->upthreshold;
+		if (data->downdifferential)
+			dfso_downdifferential = data->downdifferential;
+	}
+	if (dfso_upthreshold > 100 ||
+	    dfso_upthreshold < dfso_downdifferential)
+		return -EINVAL;
+
+	/* Assume MAX if it is going to be divided by zero */
+	if (stat->total_time == 0) {
+		*freq = DEVFREQ_MAX_FREQ;
+		return 0;
+	}
+
+	/* Prevent overflow */
+	if (stat->busy_time >= (1 << 24) || stat->total_time >= (1 << 24)) {
+		stat->busy_time >>= 7;
+		stat->total_time >>= 7;
+	}
+
+	/* Set MAX if it's busy enough */
+	if (stat->busy_time * 100 >
+	    stat->total_time * dfso_upthreshold) {
+		*freq = DEVFREQ_MAX_FREQ;
+		return 0;
+	}
+
+	/* Set MAX if we do not know the initial frequency */
+	if (stat->current_frequency == 0) {
+		*freq = DEVFREQ_MAX_FREQ;
+		return 0;
+	}
+
+	/* Keep the current frequency */
+	if (stat->busy_time * 100 >
+	    stat->total_time * (dfso_upthreshold - dfso_downdifferential)) {
+		*freq = stat->current_frequency;
+		return 0;
+	}
+
+	/* Set the desired frequency based on the load */
+	a = stat->busy_time;
+	a *= stat->current_frequency;
+	b = div_u64(a, stat->total_time);
+	b *= 100;
+	b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
+	*freq = (unsigned long) b;
+
+	return 0;
+}
+
+static int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
+				unsigned int event, void *data)
+{
+	switch (event) {
+	case DEVFREQ_GOV_START:
+		devfreq_monitor_start(devfreq);
+		break;
+
+	case DEVFREQ_GOV_STOP:
+		devfreq_monitor_stop(devfreq);
+		break;
+
+	case DEVFREQ_GOV_UPDATE_INTERVAL:
+		devfreq_update_interval(devfreq, (unsigned int *)data);
+		break;
+
+	case DEVFREQ_GOV_SUSPEND:
+		devfreq_monitor_suspend(devfreq);
+		break;
+
+	case DEVFREQ_GOV_RESUME:
+		devfreq_monitor_resume(devfreq);
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static struct devfreq_governor devfreq_simple_ondemand = {
+	.name = DEVFREQ_GOV_SIMPLE_ONDEMAND,
+	.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL
+		| DEVFREQ_GOV_ATTR_TIMER,
+	.get_target_freq = devfreq_simple_ondemand_func,
+	.event_handler = devfreq_simple_ondemand_handler,
+};
+
+static int __init devfreq_simple_ondemand_init(void)
+{
+	return devfreq_add_governor(&devfreq_simple_ondemand);
+}
+subsys_initcall(devfreq_simple_ondemand_init);
+
+static void __exit devfreq_simple_ondemand_exit(void)
+{
+	int ret;
+
+	ret = devfreq_remove_governor(&devfreq_simple_ondemand);
+	if (ret)
+		pr_err("%s: failed remove governor %d\n", __func__, ret);
+
+	return;
+}
+module_exit(devfreq_simple_ondemand_exit);
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
new file mode 100644
index 000000000..d69672cca
--- /dev/null
+++ b/drivers/devfreq/governor_userspace.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/devfreq/governor_userspace.c
+ *
+ *  Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/devfreq.h>
+#include <linux/pm.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include "governor.h"
+
+struct userspace_data {
+	unsigned long user_frequency;
+	bool valid;
+};
+
+static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
+{
+	struct userspace_data *data = df->governor_data;
+
+	if (data->valid)
+		*freq = data->user_frequency;
+	else
+		*freq = df->previous_freq; /* No user freq specified yet */
+
+	return 0;
+}
+
+static ssize_t set_freq_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct devfreq *devfreq = to_devfreq(dev);
+	struct userspace_data *data;
+	unsigned long wanted;
+	int err = 0;
+
+	mutex_lock(&devfreq->lock);
+	data = devfreq->governor_data;
+
+	sscanf(buf, "%lu", &wanted);
+	data->user_frequency = wanted;
+	data->valid = true;
+	err = update_devfreq(devfreq);
+	if (err == 0)
+		err = count;
+	mutex_unlock(&devfreq->lock);
+	return err;
+}
+
+static ssize_t set_freq_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct devfreq *devfreq = to_devfreq(dev);
+	struct userspace_data *data;
+	int err = 0;
+
+	mutex_lock(&devfreq->lock);
+	data = devfreq->governor_data;
+
+	if (data->valid)
+		err = sprintf(buf, "%lu\n", data->user_frequency);
+	else
+		err = sprintf(buf, "undefined\n");
+	mutex_unlock(&devfreq->lock);
+	return err;
+}
+
+static DEVICE_ATTR_RW(set_freq);
+static struct attribute *dev_entries[] = {
+	&dev_attr_set_freq.attr,
+	NULL,
+};
+static const struct attribute_group dev_attr_group = {
+	.name	= DEVFREQ_GOV_USERSPACE,
+	.attrs	= dev_entries,
+};
+
+static int userspace_init(struct devfreq *devfreq)
+{
+	int err = 0;
+	struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
+					      GFP_KERNEL);
+
+	if (!data) {
+		err = -ENOMEM;
+		goto out;
+	}
+	data->valid = false;
+	devfreq->governor_data = data;
+
+	err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
+out:
+	return err;
+}
+
+static void userspace_exit(struct devfreq *devfreq)
+{
+	/*
+	 * Remove the sysfs entry, unless this is being called after
+	 * device_del(), which should have done this already via kobject_del().
+	 */
+	if (devfreq->dev.kobj.sd)
+		sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
+
+	kfree(devfreq->governor_data);
+	devfreq->governor_data = NULL;
+}
+
+static int devfreq_userspace_handler(struct devfreq *devfreq,
+			unsigned int event, void *data)
+{
+	int ret = 0;
+
+	switch (event) {
+	case DEVFREQ_GOV_START:
+		ret = userspace_init(devfreq);
+		break;
+	case DEVFREQ_GOV_STOP:
+		userspace_exit(devfreq);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor devfreq_userspace = {
+	.name = DEVFREQ_GOV_USERSPACE,
+	.get_target_freq = devfreq_userspace_func,
+	.event_handler = devfreq_userspace_handler,
+};
+
+static int __init devfreq_userspace_init(void)
+{
+	return devfreq_add_governor(&devfreq_userspace);
+}
+subsys_initcall(devfreq_userspace_init);
+
+static void __exit devfreq_userspace_exit(void)
+{
+	int ret;
+
+	ret = devfreq_remove_governor(&devfreq_userspace);
+	if (ret)
+		pr_err("%s: failed remove governor %d\n", __func__, ret);
+
+	return;
+}
+module_exit(devfreq_userspace_exit);
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/imx-bus.c b/drivers/devfreq/imx-bus.c
new file mode 100644
index 000000000..a72706798
--- /dev/null
+++ b/drivers/devfreq/imx-bus.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <linux/clk.h>
+#include <linux/devfreq.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct imx_bus {
+	struct devfreq_dev_profile profile;
+	struct devfreq *devfreq;
+	struct clk *clk;
+	struct platform_device *icc_pdev;
+};
+
+static int imx_bus_target(struct device *dev,
+		unsigned long *freq, u32 flags)
+{
+	struct dev_pm_opp *new_opp;
+	int ret;
+
+	new_opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(new_opp)) {
+		ret = PTR_ERR(new_opp);
+		dev_err(dev, "failed to get recommended opp: %d\n", ret);
+		return ret;
+	}
+	dev_pm_opp_put(new_opp);
+
+	return dev_pm_opp_set_rate(dev, *freq);
+}
+
+static int imx_bus_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct imx_bus *priv = dev_get_drvdata(dev);
+
+	*freq = clk_get_rate(priv->clk);
+
+	return 0;
+}
+
+static void imx_bus_exit(struct device *dev)
+{
+	struct imx_bus *priv = dev_get_drvdata(dev);
+
+	dev_pm_opp_of_remove_table(dev);
+	platform_device_unregister(priv->icc_pdev);
+}
+
+/* imx_bus_init_icc() - register matching icc provider if required */
+static int imx_bus_init_icc(struct device *dev)
+{
+	struct imx_bus *priv = dev_get_drvdata(dev);
+	const char *icc_driver_name;
+
+	if (!of_get_property(dev->of_node, "#interconnect-cells", NULL))
+		return 0;
+	if (!IS_ENABLED(CONFIG_INTERCONNECT_IMX)) {
+		dev_warn(dev, "imx interconnect drivers disabled\n");
+		return 0;
+	}
+
+	icc_driver_name = of_device_get_match_data(dev);
+	if (!icc_driver_name) {
+		dev_err(dev, "unknown interconnect driver\n");
+		return 0;
+	}
+
+	priv->icc_pdev = platform_device_register_data(
+			dev, icc_driver_name, -1, NULL, 0);
+	if (IS_ERR(priv->icc_pdev)) {
+		dev_err(dev, "failed to register icc provider %s: %ld\n",
+				icc_driver_name, PTR_ERR(priv->icc_pdev));
+		return PTR_ERR(priv->icc_pdev);
+	}
+
+	return 0;
+}
+
+static int imx_bus_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx_bus *priv;
+	const char *gov = DEVFREQ_GOV_USERSPACE;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/*
+	 * Fetch the clock to adjust but don't explicitly enable.
+	 *
+	 * For imx bus clock clk_set_rate is safe no matter if the clock is on
+	 * or off and some peripheral side-buses might be off unless enabled by
+	 * drivers for devices on those specific buses.
+	 *
+	 * Rate adjustment on a disabled bus clock just takes effect later.
+	 */
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		ret = PTR_ERR(priv->clk);
+		dev_err(dev, "failed to fetch clk: %d\n", ret);
+		return ret;
+	}
+	platform_set_drvdata(pdev, priv);
+
+	ret = dev_pm_opp_of_add_table(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to get OPP table\n");
+		return ret;
+	}
+
+	priv->profile.target = imx_bus_target;
+	priv->profile.exit = imx_bus_exit;
+	priv->profile.get_cur_freq = imx_bus_get_cur_freq;
+	priv->profile.initial_freq = clk_get_rate(priv->clk);
+
+	priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
+						gov, NULL);
+	if (IS_ERR(priv->devfreq)) {
+		ret = PTR_ERR(priv->devfreq);
+		dev_err(dev, "failed to add devfreq device: %d\n", ret);
+		goto err;
+	}
+
+	ret = imx_bus_init_icc(dev);
+	if (ret)
+		goto err;
+
+	return 0;
+
+err:
+	dev_pm_opp_of_remove_table(dev);
+	return ret;
+}
+
+static const struct of_device_id imx_bus_of_match[] = {
+	{ .compatible = "fsl,imx8mq-noc", .data = "imx8mq-interconnect", },
+	{ .compatible = "fsl,imx8mm-noc", .data = "imx8mm-interconnect", },
+	{ .compatible = "fsl,imx8mn-noc", .data = "imx8mn-interconnect", },
+	{ .compatible = "fsl,imx8mp-noc", .data = "imx8mp-interconnect", },
+	{ .compatible = "fsl,imx8m-noc", },
+	{ .compatible = "fsl,imx8m-nic", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, imx_bus_of_match);
+
+static struct platform_driver imx_bus_platdrv = {
+	.probe		= imx_bus_probe,
+	.driver = {
+		.name	= "imx-bus-devfreq",
+		.of_match_table = imx_bus_of_match,
+	},
+};
+module_platform_driver(imx_bus_platdrv);
+
+MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
+MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/imx8m-ddrc.c b/drivers/devfreq/imx8m-ddrc.c
new file mode 100644
index 000000000..16636973e
--- /dev/null
+++ b/drivers/devfreq/imx8m-ddrc.c
@@ -0,0 +1,457 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/devfreq.h>
+#include <linux/pm_opp.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/arm-smccc.h>
+
+#define IMX_SIP_DDR_DVFS			0xc2000004
+
+/* Query available frequencies. */
+#define IMX_SIP_DDR_DVFS_GET_FREQ_COUNT		0x10
+#define IMX_SIP_DDR_DVFS_GET_FREQ_INFO		0x11
+
+/*
+ * This should be in a 1:1 mapping with devicetree OPPs but
+ * firmware provides additional info.
+ */
+struct imx8m_ddrc_freq {
+	unsigned long rate;
+	unsigned long smcarg;
+	int dram_core_parent_index;
+	int dram_alt_parent_index;
+	int dram_apb_parent_index;
+};
+
+/* Hardware limitation */
+#define IMX8M_DDRC_MAX_FREQ_COUNT 4
+
+/*
+ * i.MX8M DRAM Controller clocks have the following structure (abridged):
+ *
+ * +----------+       |\            +------+
+ * | dram_pll |-------|M| dram_core |      |
+ * +----------+       |U|---------->| D    |
+ *                 /--|X|           |  D   |
+ *   dram_alt_root |  |/            |   R  |
+ *                 |                |    C |
+ *            +---------+           |      |
+ *            |FIX DIV/4|           |      |
+ *            +---------+           |      |
+ *  composite:     |                |      |
+ * +----------+    |                |      |
+ * | dram_alt |----/                |      |
+ * +----------+                     |      |
+ * | dram_apb |-------------------->|      |
+ * +----------+                     +------+
+ *
+ * The dram_pll is used for higher rates and dram_alt is used for lower rates.
+ *
+ * Frequency switching is implemented in TF-A (via SMC call) and can change the
+ * configuration of the clocks, including mux parents. The dram_alt and
+ * dram_apb clocks are "imx composite" and their parent can change too.
+ *
+ * We need to prepare/enable the new mux parents head of switching and update
+ * their information afterwards.
+ */
+struct imx8m_ddrc {
+	struct devfreq_dev_profile profile;
+	struct devfreq *devfreq;
+
+	/* For frequency switching: */
+	struct clk *dram_core;
+	struct clk *dram_pll;
+	struct clk *dram_alt;
+	struct clk *dram_apb;
+
+	int freq_count;
+	struct imx8m_ddrc_freq freq_table[IMX8M_DDRC_MAX_FREQ_COUNT];
+};
+
+static struct imx8m_ddrc_freq *imx8m_ddrc_find_freq(struct imx8m_ddrc *priv,
+						    unsigned long rate)
+{
+	struct imx8m_ddrc_freq *freq;
+	int i;
+
+	/*
+	 * Firmware reports values in MT/s, so we round-down from Hz
+	 * Rounding is extra generous to ensure a match.
+	 */
+	rate = DIV_ROUND_CLOSEST(rate, 250000);
+	for (i = 0; i < priv->freq_count; ++i) {
+		freq = &priv->freq_table[i];
+		if (freq->rate == rate ||
+				freq->rate + 1 == rate ||
+				freq->rate - 1 == rate)
+			return freq;
+	}
+
+	return NULL;
+}
+
+static void imx8m_ddrc_smc_set_freq(int target_freq)
+{
+	struct arm_smccc_res res;
+	u32 online_cpus = 0;
+	int cpu;
+
+	local_irq_disable();
+
+	for_each_online_cpu(cpu)
+		online_cpus |= (1 << (cpu * 8));
+
+	/* change the ddr freqency */
+	arm_smccc_smc(IMX_SIP_DDR_DVFS, target_freq, online_cpus,
+			0, 0, 0, 0, 0, &res);
+
+	local_irq_enable();
+}
+
+static struct clk *clk_get_parent_by_index(struct clk *clk, int index)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_get_parent_by_index(__clk_get_hw(clk), index);
+
+	return hw ? hw->clk : NULL;
+}
+
+static int imx8m_ddrc_set_freq(struct device *dev, struct imx8m_ddrc_freq *freq)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct clk *new_dram_core_parent;
+	struct clk *new_dram_alt_parent;
+	struct clk *new_dram_apb_parent;
+	int ret;
+
+	/*
+	 * Fetch new parents
+	 *
+	 * new_dram_alt_parent and new_dram_apb_parent are optional but
+	 * new_dram_core_parent is not.
+	 */
+	new_dram_core_parent = clk_get_parent_by_index(
+			priv->dram_core, freq->dram_core_parent_index - 1);
+	if (!new_dram_core_parent) {
+		dev_err(dev, "failed to fetch new dram_core parent\n");
+		return -EINVAL;
+	}
+	if (freq->dram_alt_parent_index) {
+		new_dram_alt_parent = clk_get_parent_by_index(
+				priv->dram_alt,
+				freq->dram_alt_parent_index - 1);
+		if (!new_dram_alt_parent) {
+			dev_err(dev, "failed to fetch new dram_alt parent\n");
+			return -EINVAL;
+		}
+	} else
+		new_dram_alt_parent = NULL;
+
+	if (freq->dram_apb_parent_index) {
+		new_dram_apb_parent = clk_get_parent_by_index(
+				priv->dram_apb,
+				freq->dram_apb_parent_index - 1);
+		if (!new_dram_apb_parent) {
+			dev_err(dev, "failed to fetch new dram_apb parent\n");
+			return -EINVAL;
+		}
+	} else
+		new_dram_apb_parent = NULL;
+
+	/* increase reference counts and ensure clks are ON before switch */
+	ret = clk_prepare_enable(new_dram_core_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_core parent: %d\n",
+			ret);
+		goto out;
+	}
+	ret = clk_prepare_enable(new_dram_alt_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_alt parent: %d\n",
+			ret);
+		goto out_disable_core_parent;
+	}
+	ret = clk_prepare_enable(new_dram_apb_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_apb parent: %d\n",
+			ret);
+		goto out_disable_alt_parent;
+	}
+
+	imx8m_ddrc_smc_set_freq(freq->smcarg);
+
+	/* update parents in clk tree after switch. */
+	ret = clk_set_parent(priv->dram_core, new_dram_core_parent);
+	if (ret)
+		dev_warn(dev, "failed to set dram_core parent: %d\n", ret);
+	if (new_dram_alt_parent) {
+		ret = clk_set_parent(priv->dram_alt, new_dram_alt_parent);
+		if (ret)
+			dev_warn(dev, "failed to set dram_alt parent: %d\n",
+				 ret);
+	}
+	if (new_dram_apb_parent) {
+		ret = clk_set_parent(priv->dram_apb, new_dram_apb_parent);
+		if (ret)
+			dev_warn(dev, "failed to set dram_apb parent: %d\n",
+				 ret);
+	}
+
+	/*
+	 * Explicitly refresh dram PLL rate.
+	 *
+	 * Even if it's marked with CLK_GET_RATE_NOCACHE the rate will not be
+	 * automatically refreshed when clk_get_rate is called on children.
+	 */
+	clk_get_rate(priv->dram_pll);
+
+	/*
+	 * clk_set_parent transfer the reference count from old parent.
+	 * now we drop extra reference counts used during the switch
+	 */
+	clk_disable_unprepare(new_dram_apb_parent);
+out_disable_alt_parent:
+	clk_disable_unprepare(new_dram_alt_parent);
+out_disable_core_parent:
+	clk_disable_unprepare(new_dram_core_parent);
+out:
+	return ret;
+}
+
+static int imx8m_ddrc_target(struct device *dev, unsigned long *freq, u32 flags)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct imx8m_ddrc_freq *freq_info;
+	struct dev_pm_opp *new_opp;
+	unsigned long old_freq, new_freq;
+	int ret;
+
+	new_opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(new_opp)) {
+		ret = PTR_ERR(new_opp);
+		dev_err(dev, "failed to get recommended opp: %d\n", ret);
+		return ret;
+	}
+	dev_pm_opp_put(new_opp);
+
+	old_freq = clk_get_rate(priv->dram_core);
+	if (*freq == old_freq)
+		return 0;
+
+	freq_info = imx8m_ddrc_find_freq(priv, *freq);
+	if (!freq_info)
+		return -EINVAL;
+
+	/*
+	 * Read back the clk rate to verify switch was correct and so that
+	 * we can report it on all error paths.
+	 */
+	ret = imx8m_ddrc_set_freq(dev, freq_info);
+
+	new_freq = clk_get_rate(priv->dram_core);
+	if (ret)
+		dev_err(dev, "ddrc failed freq switch to %lu from %lu: error %d. now at %lu\n",
+			*freq, old_freq, ret, new_freq);
+	else if (*freq != new_freq)
+		dev_err(dev, "ddrc failed freq update to %lu from %lu, now at %lu\n",
+			*freq, old_freq, new_freq);
+	else
+		dev_dbg(dev, "ddrc freq set to %lu (was %lu)\n",
+			*freq, old_freq);
+
+	return ret;
+}
+
+static int imx8m_ddrc_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+
+	*freq = clk_get_rate(priv->dram_core);
+
+	return 0;
+}
+
+static int imx8m_ddrc_init_freq_info(struct device *dev)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct arm_smccc_res res;
+	int index;
+
+	/* An error here means DDR DVFS API not supported by firmware */
+	arm_smccc_smc(IMX_SIP_DDR_DVFS, IMX_SIP_DDR_DVFS_GET_FREQ_COUNT,
+			0, 0, 0, 0, 0, 0, &res);
+	priv->freq_count = res.a0;
+	if (priv->freq_count <= 0 ||
+			priv->freq_count > IMX8M_DDRC_MAX_FREQ_COUNT)
+		return -ENODEV;
+
+	for (index = 0; index < priv->freq_count; ++index) {
+		struct imx8m_ddrc_freq *freq = &priv->freq_table[index];
+
+		arm_smccc_smc(IMX_SIP_DDR_DVFS, IMX_SIP_DDR_DVFS_GET_FREQ_INFO,
+			      index, 0, 0, 0, 0, 0, &res);
+		/* Result should be strictly positive */
+		if ((long)res.a0 <= 0)
+			return -ENODEV;
+
+		freq->rate = res.a0;
+		freq->smcarg = index;
+		freq->dram_core_parent_index = res.a1;
+		freq->dram_alt_parent_index = res.a2;
+		freq->dram_apb_parent_index = res.a3;
+
+		/* dram_core has 2 options: dram_pll or dram_alt_root */
+		if (freq->dram_core_parent_index != 1 &&
+				freq->dram_core_parent_index != 2)
+			return -ENODEV;
+		/* dram_apb and dram_alt have exactly 8 possible parents */
+		if (freq->dram_alt_parent_index > 8 ||
+				freq->dram_apb_parent_index > 8)
+			return -ENODEV;
+		/* dram_core from alt requires explicit dram_alt parent */
+		if (freq->dram_core_parent_index == 2 &&
+				freq->dram_alt_parent_index == 0)
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int imx8m_ddrc_check_opps(struct device *dev)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct imx8m_ddrc_freq *freq_info;
+	struct dev_pm_opp *opp;
+	unsigned long freq;
+	int i, opp_count;
+
+	/* Enumerate DT OPPs and disable those not supported by firmware */
+	opp_count = dev_pm_opp_get_opp_count(dev);
+	if (opp_count < 0)
+		return opp_count;
+	for (i = 0, freq = 0; i < opp_count; ++i, ++freq) {
+		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+		if (IS_ERR(opp)) {
+			dev_err(dev, "Failed enumerating OPPs: %ld\n",
+				PTR_ERR(opp));
+			return PTR_ERR(opp);
+		}
+		dev_pm_opp_put(opp);
+
+		freq_info = imx8m_ddrc_find_freq(priv, freq);
+		if (!freq_info) {
+			dev_info(dev, "Disable unsupported OPP %luHz %luMT/s\n",
+					freq, DIV_ROUND_CLOSEST(freq, 250000));
+			dev_pm_opp_disable(dev, freq);
+		}
+	}
+
+	return 0;
+}
+
+static void imx8m_ddrc_exit(struct device *dev)
+{
+	dev_pm_opp_of_remove_table(dev);
+}
+
+static int imx8m_ddrc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx8m_ddrc *priv;
+	const char *gov = DEVFREQ_GOV_USERSPACE;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = imx8m_ddrc_init_freq_info(dev);
+	if (ret) {
+		dev_err(dev, "failed to init firmware freq info: %d\n", ret);
+		return ret;
+	}
+
+	priv->dram_core = devm_clk_get(dev, "core");
+	if (IS_ERR(priv->dram_core)) {
+		ret = PTR_ERR(priv->dram_core);
+		dev_err(dev, "failed to fetch core clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_pll = devm_clk_get(dev, "pll");
+	if (IS_ERR(priv->dram_pll)) {
+		ret = PTR_ERR(priv->dram_pll);
+		dev_err(dev, "failed to fetch pll clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_alt = devm_clk_get(dev, "alt");
+	if (IS_ERR(priv->dram_alt)) {
+		ret = PTR_ERR(priv->dram_alt);
+		dev_err(dev, "failed to fetch alt clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_apb = devm_clk_get(dev, "apb");
+	if (IS_ERR(priv->dram_apb)) {
+		ret = PTR_ERR(priv->dram_apb);
+		dev_err(dev, "failed to fetch apb clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = dev_pm_opp_of_add_table(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to get OPP table\n");
+		return ret;
+	}
+
+	ret = imx8m_ddrc_check_opps(dev);
+	if (ret < 0)
+		goto err;
+
+	priv->profile.target = imx8m_ddrc_target;
+	priv->profile.exit = imx8m_ddrc_exit;
+	priv->profile.get_cur_freq = imx8m_ddrc_get_cur_freq;
+	priv->profile.initial_freq = clk_get_rate(priv->dram_core);
+
+	priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
+						gov, NULL);
+	if (IS_ERR(priv->devfreq)) {
+		ret = PTR_ERR(priv->devfreq);
+		dev_err(dev, "failed to add devfreq device: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	dev_pm_opp_of_remove_table(dev);
+	return ret;
+}
+
+static const struct of_device_id imx8m_ddrc_of_match[] = {
+	{ .compatible = "fsl,imx8m-ddrc", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, imx8m_ddrc_of_match);
+
+static struct platform_driver imx8m_ddrc_platdrv = {
+	.probe		= imx8m_ddrc_probe,
+	.driver = {
+		.name	= "imx8m-ddrc-devfreq",
+		.of_match_table = imx8m_ddrc_of_match,
+	},
+};
+module_platform_driver(imx8m_ddrc_platdrv);
+
+MODULE_DESCRIPTION("i.MX8M DDR Controller frequency driver");
+MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c
new file mode 100644
index 000000000..e5458ada5
--- /dev/null
+++ b/drivers/devfreq/mtk-cci-devfreq.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 MediaTek Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/devfreq.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
+
+struct mtk_ccifreq_platform_data {
+	int min_volt_shift;
+	int max_volt_shift;
+	int proc_max_volt;
+	int sram_min_volt;
+	int sram_max_volt;
+};
+
+struct mtk_ccifreq_drv {
+	struct device *dev;
+	struct devfreq *devfreq;
+	struct regulator *proc_reg;
+	struct regulator *sram_reg;
+	struct clk *cci_clk;
+	struct clk *inter_clk;
+	int inter_voltage;
+	unsigned long pre_freq;
+	/* Avoid race condition for regulators between notify and policy */
+	struct mutex reg_lock;
+	struct notifier_block opp_nb;
+	const struct mtk_ccifreq_platform_data *soc_data;
+	int vtrack_max;
+};
+
+static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, int new_voltage)
+{
+	const struct mtk_ccifreq_platform_data *soc_data = drv->soc_data;
+	struct device *dev = drv->dev;
+	int pre_voltage, pre_vsram, new_vsram, vsram, voltage, ret;
+	int retry_max = drv->vtrack_max;
+
+	if (!drv->sram_reg) {
+		ret = regulator_set_voltage(drv->proc_reg, new_voltage,
+					    drv->soc_data->proc_max_volt);
+		return ret;
+	}
+
+	pre_voltage = regulator_get_voltage(drv->proc_reg);
+	if (pre_voltage < 0) {
+		dev_err(dev, "invalid vproc value: %d\n", pre_voltage);
+		return pre_voltage;
+	}
+
+	pre_vsram = regulator_get_voltage(drv->sram_reg);
+	if (pre_vsram < 0) {
+		dev_err(dev, "invalid vsram value: %d\n", pre_vsram);
+		return pre_vsram;
+	}
+
+	new_vsram = clamp(new_voltage + soc_data->min_volt_shift,
+			  soc_data->sram_min_volt, soc_data->sram_max_volt);
+
+	do {
+		if (pre_voltage <= new_voltage) {
+			vsram = clamp(pre_voltage + soc_data->max_volt_shift,
+				      soc_data->sram_min_volt, new_vsram);
+			ret = regulator_set_voltage(drv->sram_reg, vsram,
+						    soc_data->sram_max_volt);
+			if (ret)
+				return ret;
+
+			if (vsram == soc_data->sram_max_volt ||
+			    new_vsram == soc_data->sram_min_volt)
+				voltage = new_voltage;
+			else
+				voltage = vsram - soc_data->min_volt_shift;
+
+			ret = regulator_set_voltage(drv->proc_reg, voltage,
+						    soc_data->proc_max_volt);
+			if (ret) {
+				regulator_set_voltage(drv->sram_reg, pre_vsram,
+						      soc_data->sram_max_volt);
+				return ret;
+			}
+		} else if (pre_voltage > new_voltage) {
+			voltage = max(new_voltage,
+				      pre_vsram - soc_data->max_volt_shift);
+			ret = regulator_set_voltage(drv->proc_reg, voltage,
+						    soc_data->proc_max_volt);
+			if (ret)
+				return ret;
+
+			if (voltage == new_voltage)
+				vsram = new_vsram;
+			else
+				vsram = max(new_vsram,
+					    voltage + soc_data->min_volt_shift);
+
+			ret = regulator_set_voltage(drv->sram_reg, vsram,
+						    soc_data->sram_max_volt);
+			if (ret) {
+				regulator_set_voltage(drv->proc_reg, pre_voltage,
+						      soc_data->proc_max_volt);
+				return ret;
+			}
+		}
+
+		pre_voltage = voltage;
+		pre_vsram = vsram;
+
+		if (--retry_max < 0) {
+			dev_err(dev,
+				"over loop count, failed to set voltage\n");
+			return -EINVAL;
+		}
+	} while (voltage != new_voltage || vsram != new_vsram);
+
+	return 0;
+}
+
+static int mtk_ccifreq_target(struct device *dev, unsigned long *freq,
+			      u32 flags)
+{
+	struct mtk_ccifreq_drv *drv = dev_get_drvdata(dev);
+	struct clk *cci_pll = clk_get_parent(drv->cci_clk);
+	struct dev_pm_opp *opp;
+	unsigned long opp_rate;
+	int voltage, pre_voltage, inter_voltage, target_voltage, ret;
+
+	if (!drv)
+		return -EINVAL;
+
+	if (drv->pre_freq == *freq)
+		return 0;
+
+	inter_voltage = drv->inter_voltage;
+
+	opp_rate = *freq;
+	opp = devfreq_recommended_opp(dev, &opp_rate, 1);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "failed to find opp for freq: %ld\n", opp_rate);
+		return PTR_ERR(opp);
+	}
+
+	mutex_lock(&drv->reg_lock);
+
+	voltage = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+
+	pre_voltage = regulator_get_voltage(drv->proc_reg);
+	if (pre_voltage < 0) {
+		dev_err(dev, "invalid vproc value: %d\n", pre_voltage);
+		ret = pre_voltage;
+		goto out_unlock;
+	}
+
+	/* scale up: set voltage first then freq. */
+	target_voltage = max(inter_voltage, voltage);
+	if (pre_voltage <= target_voltage) {
+		ret = mtk_ccifreq_set_voltage(drv, target_voltage);
+		if (ret) {
+			dev_err(dev, "failed to scale up voltage\n");
+			goto out_restore_voltage;
+		}
+	}
+
+	/* switch the cci clock to intermediate clock source. */
+	ret = clk_set_parent(drv->cci_clk, drv->inter_clk);
+	if (ret) {
+		dev_err(dev, "failed to re-parent cci clock\n");
+		goto out_restore_voltage;
+	}
+
+	/* set the original clock to target rate. */
+	ret = clk_set_rate(cci_pll, *freq);
+	if (ret) {
+		dev_err(dev, "failed to set cci pll rate: %d\n", ret);
+		clk_set_parent(drv->cci_clk, cci_pll);
+		goto out_restore_voltage;
+	}
+
+	/* switch the cci clock back to the original clock source. */
+	ret = clk_set_parent(drv->cci_clk, cci_pll);
+	if (ret) {
+		dev_err(dev, "failed to re-parent cci clock\n");
+		mtk_ccifreq_set_voltage(drv, inter_voltage);
+		goto out_unlock;
+	}
+
+	/*
+	 * If the new voltage is lower than the intermediate voltage or the
+	 * original voltage, scale down to the new voltage.
+	 */
+	if (voltage < inter_voltage || voltage < pre_voltage) {
+		ret = mtk_ccifreq_set_voltage(drv, voltage);
+		if (ret) {
+			dev_err(dev, "failed to scale down voltage\n");
+			goto out_unlock;
+		}
+	}
+
+	drv->pre_freq = *freq;
+	mutex_unlock(&drv->reg_lock);
+
+	return 0;
+
+out_restore_voltage:
+	mtk_ccifreq_set_voltage(drv, pre_voltage);
+
+out_unlock:
+	mutex_unlock(&drv->reg_lock);
+	return ret;
+}
+
+static int mtk_ccifreq_opp_notifier(struct notifier_block *nb,
+				    unsigned long event, void *data)
+{
+	struct dev_pm_opp *opp = data;
+	struct mtk_ccifreq_drv *drv;
+	unsigned long freq, volt;
+
+	drv = container_of(nb, struct mtk_ccifreq_drv, opp_nb);
+
+	if (event == OPP_EVENT_ADJUST_VOLTAGE) {
+		freq = dev_pm_opp_get_freq(opp);
+
+		mutex_lock(&drv->reg_lock);
+		/* current opp item is changed */
+		if (freq == drv->pre_freq) {
+			volt = dev_pm_opp_get_voltage(opp);
+			mtk_ccifreq_set_voltage(drv, volt);
+		}
+		mutex_unlock(&drv->reg_lock);
+	}
+
+	return 0;
+}
+
+static struct devfreq_dev_profile mtk_ccifreq_profile = {
+	.target = mtk_ccifreq_target,
+};
+
+static int mtk_ccifreq_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_ccifreq_drv *drv;
+	struct devfreq_passive_data *passive_data;
+	struct dev_pm_opp *opp;
+	unsigned long rate, opp_volt;
+	int ret;
+
+	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	drv->dev = dev;
+	drv->soc_data = (const struct mtk_ccifreq_platform_data *)
+				of_device_get_match_data(&pdev->dev);
+	mutex_init(&drv->reg_lock);
+	platform_set_drvdata(pdev, drv);
+
+	drv->cci_clk = devm_clk_get(dev, "cci");
+	if (IS_ERR(drv->cci_clk)) {
+		ret = PTR_ERR(drv->cci_clk);
+		return dev_err_probe(dev, ret, "failed to get cci clk\n");
+	}
+
+	drv->inter_clk = devm_clk_get(dev, "intermediate");
+	if (IS_ERR(drv->inter_clk)) {
+		ret = PTR_ERR(drv->inter_clk);
+		return dev_err_probe(dev, ret,
+				     "failed to get intermediate clk\n");
+	}
+
+	drv->proc_reg = devm_regulator_get_optional(dev, "proc");
+	if (IS_ERR(drv->proc_reg)) {
+		ret = PTR_ERR(drv->proc_reg);
+		return dev_err_probe(dev, ret,
+				     "failed to get proc regulator\n");
+	}
+
+	ret = regulator_enable(drv->proc_reg);
+	if (ret) {
+		dev_err(dev, "failed to enable proc regulator\n");
+		return ret;
+	}
+
+	drv->sram_reg = devm_regulator_get_optional(dev, "sram");
+	if (IS_ERR(drv->sram_reg)) {
+		ret = PTR_ERR(drv->sram_reg);
+		if (ret == -EPROBE_DEFER)
+			goto out_free_resources;
+
+		drv->sram_reg = NULL;
+	} else {
+		ret = regulator_enable(drv->sram_reg);
+		if (ret) {
+			dev_err(dev, "failed to enable sram regulator\n");
+			goto out_free_resources;
+		}
+	}
+
+	/*
+	 * We assume min voltage is 0 and tracking target voltage using
+	 * min_volt_shift for each iteration.
+	 * The retry_max is 3 times of expected iteration count.
+	 */
+	drv->vtrack_max = 3 * DIV_ROUND_UP(max(drv->soc_data->sram_max_volt,
+					       drv->soc_data->proc_max_volt),
+					   drv->soc_data->min_volt_shift);
+
+	ret = clk_prepare_enable(drv->cci_clk);
+	if (ret)
+		goto out_free_resources;
+
+	ret = dev_pm_opp_of_add_table(dev);
+	if (ret) {
+		dev_err(dev, "failed to add opp table: %d\n", ret);
+		goto out_disable_cci_clk;
+	}
+
+	rate = clk_get_rate(drv->inter_clk);
+	opp = dev_pm_opp_find_freq_ceil(dev, &rate);
+	if (IS_ERR(opp)) {
+		ret = PTR_ERR(opp);
+		dev_err(dev, "failed to get intermediate opp: %d\n", ret);
+		goto out_remove_opp_table;
+	}
+	drv->inter_voltage = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+
+	rate = U32_MAX;
+	opp = dev_pm_opp_find_freq_floor(drv->dev, &rate);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "failed to get opp\n");
+		ret = PTR_ERR(opp);
+		goto out_remove_opp_table;
+	}
+
+	opp_volt = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+	ret = mtk_ccifreq_set_voltage(drv, opp_volt);
+	if (ret) {
+		dev_err(dev, "failed to scale to highest voltage %lu in proc_reg\n",
+			opp_volt);
+		goto out_remove_opp_table;
+	}
+
+	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
+	if (!passive_data) {
+		ret = -ENOMEM;
+		goto out_remove_opp_table;
+	}
+
+	passive_data->parent_type = CPUFREQ_PARENT_DEV;
+	drv->devfreq = devm_devfreq_add_device(dev, &mtk_ccifreq_profile,
+					       DEVFREQ_GOV_PASSIVE,
+					       passive_data);
+	if (IS_ERR(drv->devfreq)) {
+		ret = -EPROBE_DEFER;
+		dev_err(dev, "failed to add devfreq device: %ld\n",
+			PTR_ERR(drv->devfreq));
+		goto out_remove_opp_table;
+	}
+
+	drv->opp_nb.notifier_call = mtk_ccifreq_opp_notifier;
+	ret = dev_pm_opp_register_notifier(dev, &drv->opp_nb);
+	if (ret) {
+		dev_err(dev, "failed to register opp notifier: %d\n", ret);
+		goto out_remove_opp_table;
+	}
+	return 0;
+
+out_remove_opp_table:
+	dev_pm_opp_of_remove_table(dev);
+
+out_disable_cci_clk:
+	clk_disable_unprepare(drv->cci_clk);
+
+out_free_resources:
+	if (regulator_is_enabled(drv->proc_reg))
+		regulator_disable(drv->proc_reg);
+	if (drv->sram_reg && regulator_is_enabled(drv->sram_reg))
+		regulator_disable(drv->sram_reg);
+
+	return ret;
+}
+
+static int mtk_ccifreq_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_ccifreq_drv *drv;
+
+	drv = platform_get_drvdata(pdev);
+
+	dev_pm_opp_unregister_notifier(dev, &drv->opp_nb);
+	dev_pm_opp_of_remove_table(dev);
+	clk_disable_unprepare(drv->cci_clk);
+	regulator_disable(drv->proc_reg);
+	if (drv->sram_reg)
+		regulator_disable(drv->sram_reg);
+
+	return 0;
+}
+
+static const struct mtk_ccifreq_platform_data mt8183_platform_data = {
+	.min_volt_shift = 100000,
+	.max_volt_shift = 200000,
+	.proc_max_volt = 1150000,
+};
+
+static const struct mtk_ccifreq_platform_data mt8186_platform_data = {
+	.min_volt_shift = 100000,
+	.max_volt_shift = 250000,
+	.proc_max_volt = 1118750,
+	.sram_min_volt = 850000,
+	.sram_max_volt = 1118750,
+};
+
+static const struct of_device_id mtk_ccifreq_machines[] = {
+	{ .compatible = "mediatek,mt8183-cci", .data = &mt8183_platform_data },
+	{ .compatible = "mediatek,mt8186-cci", .data = &mt8186_platform_data },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mtk_ccifreq_machines);
+
+static struct platform_driver mtk_ccifreq_platdrv = {
+	.probe	= mtk_ccifreq_probe,
+	.remove	= mtk_ccifreq_remove,
+	.driver = {
+		.name = "mtk-ccifreq",
+		.of_match_table = mtk_ccifreq_machines,
+	},
+};
+module_platform_driver(mtk_ccifreq_platdrv);
+
+MODULE_DESCRIPTION("MediaTek CCI devfreq driver");
+MODULE_AUTHOR("Jia-Wei Chang <jia-wei.chang@mediatek.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
new file mode 100644
index 000000000..daff40702
--- /dev/null
+++ b/drivers/devfreq/rk3399_dmc.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd.
+ * Author: Lin Huang <hl@rock-chips.com>
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/devfreq.h>
+#include <linux/devfreq-event.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/rwsem.h>
+#include <linux/suspend.h>
+
+#include <soc/rockchip/pm_domains.h>
+#include <soc/rockchip/rk3399_grf.h>
+#include <soc/rockchip/rockchip_sip.h>
+
+#define NS_TO_CYCLE(NS, MHz)				(((NS) * (MHz)) / NSEC_PER_USEC)
+
+#define RK3399_SET_ODT_PD_0_SR_IDLE			GENMASK(7, 0)
+#define RK3399_SET_ODT_PD_0_SR_MC_GATE_IDLE		GENMASK(15, 8)
+#define RK3399_SET_ODT_PD_0_STANDBY_IDLE		GENMASK(31, 16)
+
+#define RK3399_SET_ODT_PD_1_PD_IDLE			GENMASK(11, 0)
+#define RK3399_SET_ODT_PD_1_SRPD_LITE_IDLE		GENMASK(27, 16)
+
+#define RK3399_SET_ODT_PD_2_ODT_ENABLE			BIT(0)
+
+struct rk3399_dmcfreq {
+	struct device *dev;
+	struct devfreq *devfreq;
+	struct devfreq_dev_profile profile;
+	struct devfreq_simple_ondemand_data ondemand_data;
+	struct clk *dmc_clk;
+	struct devfreq_event_dev *edev;
+	struct mutex lock;
+	struct regulator *vdd_center;
+	struct regmap *regmap_pmu;
+	unsigned long rate, target_rate;
+	unsigned long volt, target_volt;
+	unsigned int odt_dis_freq;
+
+	unsigned int pd_idle_ns;
+	unsigned int sr_idle_ns;
+	unsigned int sr_mc_gate_idle_ns;
+	unsigned int srpd_lite_idle_ns;
+	unsigned int standby_idle_ns;
+	unsigned int ddr3_odt_dis_freq;
+	unsigned int lpddr3_odt_dis_freq;
+	unsigned int lpddr4_odt_dis_freq;
+
+	unsigned int pd_idle_dis_freq;
+	unsigned int sr_idle_dis_freq;
+	unsigned int sr_mc_gate_idle_dis_freq;
+	unsigned int srpd_lite_idle_dis_freq;
+	unsigned int standby_idle_dis_freq;
+};
+
+static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
+				 u32 flags)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	struct dev_pm_opp *opp;
+	unsigned long old_clk_rate = dmcfreq->rate;
+	unsigned long target_volt, target_rate;
+	unsigned int ddrcon_mhz;
+	struct arm_smccc_res res;
+	int err;
+
+	u32 odt_pd_arg0 = 0;
+	u32 odt_pd_arg1 = 0;
+	u32 odt_pd_arg2 = 0;
+
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp))
+		return PTR_ERR(opp);
+
+	target_rate = dev_pm_opp_get_freq(opp);
+	target_volt = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+
+	if (dmcfreq->rate == target_rate)
+		return 0;
+
+	mutex_lock(&dmcfreq->lock);
+
+	/*
+	 * Ensure power-domain transitions don't interfere with ARM Trusted
+	 * Firmware power-domain idling.
+	 */
+	err = rockchip_pmu_block();
+	if (err) {
+		dev_err(dev, "Failed to block PMU: %d\n", err);
+		goto out_unlock;
+	}
+
+	/*
+	 * Some idle parameters may be based on the DDR controller clock, which
+	 * is half of the DDR frequency.
+	 * pd_idle and standby_idle are based on the controller clock cycle.
+	 * sr_idle_cycle, sr_mc_gate_idle_cycle, and srpd_lite_idle_cycle
+	 * are based on the 1024 controller clock cycle
+	 */
+	ddrcon_mhz = target_rate / USEC_PER_SEC / 2;
+
+	u32p_replace_bits(&odt_pd_arg1,
+			  NS_TO_CYCLE(dmcfreq->pd_idle_ns, ddrcon_mhz),
+			  RK3399_SET_ODT_PD_1_PD_IDLE);
+	u32p_replace_bits(&odt_pd_arg0,
+			  NS_TO_CYCLE(dmcfreq->standby_idle_ns, ddrcon_mhz),
+			  RK3399_SET_ODT_PD_0_STANDBY_IDLE);
+	u32p_replace_bits(&odt_pd_arg0,
+			  DIV_ROUND_UP(NS_TO_CYCLE(dmcfreq->sr_idle_ns,
+						   ddrcon_mhz), 1024),
+			  RK3399_SET_ODT_PD_0_SR_IDLE);
+	u32p_replace_bits(&odt_pd_arg0,
+			  DIV_ROUND_UP(NS_TO_CYCLE(dmcfreq->sr_mc_gate_idle_ns,
+						   ddrcon_mhz), 1024),
+			  RK3399_SET_ODT_PD_0_SR_MC_GATE_IDLE);
+	u32p_replace_bits(&odt_pd_arg1,
+			  DIV_ROUND_UP(NS_TO_CYCLE(dmcfreq->srpd_lite_idle_ns,
+						   ddrcon_mhz), 1024),
+			  RK3399_SET_ODT_PD_1_SRPD_LITE_IDLE);
+
+	if (dmcfreq->regmap_pmu) {
+		if (target_rate >= dmcfreq->sr_idle_dis_freq)
+			odt_pd_arg0 &= ~RK3399_SET_ODT_PD_0_SR_IDLE;
+
+		if (target_rate >= dmcfreq->sr_mc_gate_idle_dis_freq)
+			odt_pd_arg0 &= ~RK3399_SET_ODT_PD_0_SR_MC_GATE_IDLE;
+
+		if (target_rate >= dmcfreq->standby_idle_dis_freq)
+			odt_pd_arg0 &= ~RK3399_SET_ODT_PD_0_STANDBY_IDLE;
+
+		if (target_rate >= dmcfreq->pd_idle_dis_freq)
+			odt_pd_arg1 &= ~RK3399_SET_ODT_PD_1_PD_IDLE;
+
+		if (target_rate >= dmcfreq->srpd_lite_idle_dis_freq)
+			odt_pd_arg1 &= ~RK3399_SET_ODT_PD_1_SRPD_LITE_IDLE;
+
+		if (target_rate >= dmcfreq->odt_dis_freq)
+			odt_pd_arg2 |= RK3399_SET_ODT_PD_2_ODT_ENABLE;
+
+		/*
+		 * This makes a SMC call to the TF-A to set the DDR PD
+		 * (power-down) timings and to enable or disable the
+		 * ODT (on-die termination) resistors.
+		 */
+		arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, odt_pd_arg0, odt_pd_arg1,
+			      ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD, odt_pd_arg2,
+			      0, 0, 0, &res);
+	}
+
+	/*
+	 * If frequency scaling from low to high, adjust voltage first.
+	 * If frequency scaling from high to low, adjust frequency first.
+	 */
+	if (old_clk_rate < target_rate) {
+		err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
+					    target_volt);
+		if (err) {
+			dev_err(dev, "Cannot set voltage %lu uV\n",
+				target_volt);
+			goto out;
+		}
+	}
+
+	err = clk_set_rate(dmcfreq->dmc_clk, target_rate);
+	if (err) {
+		dev_err(dev, "Cannot set frequency %lu (%d)\n", target_rate,
+			err);
+		regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
+				      dmcfreq->volt);
+		goto out;
+	}
+
+	/*
+	 * Check the dpll rate,
+	 * There only two result we will get,
+	 * 1. Ddr frequency scaling fail, we still get the old rate.
+	 * 2. Ddr frequency scaling sucessful, we get the rate we set.
+	 */
+	dmcfreq->rate = clk_get_rate(dmcfreq->dmc_clk);
+
+	/* If get the incorrect rate, set voltage to old value. */
+	if (dmcfreq->rate != target_rate) {
+		dev_err(dev, "Got wrong frequency, Request %lu, Current %lu\n",
+			target_rate, dmcfreq->rate);
+		regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
+				      dmcfreq->volt);
+		goto out;
+	} else if (old_clk_rate > target_rate)
+		err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
+					    target_volt);
+	if (err)
+		dev_err(dev, "Cannot set voltage %lu uV\n", target_volt);
+
+	dmcfreq->rate = target_rate;
+	dmcfreq->volt = target_volt;
+
+out:
+	rockchip_pmu_unblock();
+out_unlock:
+	mutex_unlock(&dmcfreq->lock);
+	return err;
+}
+
+static int rk3399_dmcfreq_get_dev_status(struct device *dev,
+					 struct devfreq_dev_status *stat)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	struct devfreq_event_data edata;
+	int ret = 0;
+
+	ret = devfreq_event_get_event(dmcfreq->edev, &edata);
+	if (ret < 0)
+		return ret;
+
+	stat->current_frequency = dmcfreq->rate;
+	stat->busy_time = edata.load_count;
+	stat->total_time = edata.total_count;
+
+	return ret;
+}
+
+static int rk3399_dmcfreq_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+
+	*freq = dmcfreq->rate;
+
+	return 0;
+}
+
+static __maybe_unused int rk3399_dmcfreq_suspend(struct device *dev)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = devfreq_event_disable_edev(dmcfreq->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to disable the devfreq-event devices\n");
+		return ret;
+	}
+
+	ret = devfreq_suspend_device(dmcfreq->devfreq);
+	if (ret < 0) {
+		dev_err(dev, "failed to suspend the devfreq devices\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static __maybe_unused int rk3399_dmcfreq_resume(struct device *dev)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = devfreq_event_enable_edev(dmcfreq->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable the devfreq-event devices\n");
+		return ret;
+	}
+
+	ret = devfreq_resume_device(dmcfreq->devfreq);
+	if (ret < 0) {
+		dev_err(dev, "failed to resume the devfreq devices\n");
+		return ret;
+	}
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(rk3399_dmcfreq_pm, rk3399_dmcfreq_suspend,
+			 rk3399_dmcfreq_resume);
+
+static int rk3399_dmcfreq_of_props(struct rk3399_dmcfreq *data,
+				   struct device_node *np)
+{
+	int ret = 0;
+
+	/*
+	 * These are all optional, and serve as minimum bounds. Give them large
+	 * (i.e., never "disabled") values if the DT doesn't specify one.
+	 */
+	data->pd_idle_dis_freq =
+		data->sr_idle_dis_freq =
+		data->sr_mc_gate_idle_dis_freq =
+		data->srpd_lite_idle_dis_freq =
+		data->standby_idle_dis_freq = UINT_MAX;
+
+	ret |= of_property_read_u32(np, "rockchip,pd-idle-ns",
+				    &data->pd_idle_ns);
+	ret |= of_property_read_u32(np, "rockchip,sr-idle-ns",
+				    &data->sr_idle_ns);
+	ret |= of_property_read_u32(np, "rockchip,sr-mc-gate-idle-ns",
+				    &data->sr_mc_gate_idle_ns);
+	ret |= of_property_read_u32(np, "rockchip,srpd-lite-idle-ns",
+				    &data->srpd_lite_idle_ns);
+	ret |= of_property_read_u32(np, "rockchip,standby-idle-ns",
+				    &data->standby_idle_ns);
+	ret |= of_property_read_u32(np, "rockchip,ddr3_odt_dis_freq",
+				    &data->ddr3_odt_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,lpddr3_odt_dis_freq",
+				    &data->lpddr3_odt_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,lpddr4_odt_dis_freq",
+				    &data->lpddr4_odt_dis_freq);
+
+	ret |= of_property_read_u32(np, "rockchip,pd-idle-dis-freq-hz",
+				    &data->pd_idle_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,sr-idle-dis-freq-hz",
+				    &data->sr_idle_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,sr-mc-gate-idle-dis-freq-hz",
+				    &data->sr_mc_gate_idle_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,srpd-lite-idle-dis-freq-hz",
+				    &data->srpd_lite_idle_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,standby-idle-dis-freq-hz",
+				    &data->standby_idle_dis_freq);
+
+	return ret;
+}
+
+static int rk3399_dmcfreq_probe(struct platform_device *pdev)
+{
+	struct arm_smccc_res res;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node, *node;
+	struct rk3399_dmcfreq *data;
+	int ret;
+	struct dev_pm_opp *opp;
+	u32 ddr_type;
+	u32 val;
+
+	data = devm_kzalloc(dev, sizeof(struct rk3399_dmcfreq), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mutex_init(&data->lock);
+
+	data->vdd_center = devm_regulator_get(dev, "center");
+	if (IS_ERR(data->vdd_center))
+		return dev_err_probe(dev, PTR_ERR(data->vdd_center),
+				     "Cannot get the regulator \"center\"\n");
+
+	data->dmc_clk = devm_clk_get(dev, "dmc_clk");
+	if (IS_ERR(data->dmc_clk))
+		return dev_err_probe(dev, PTR_ERR(data->dmc_clk),
+				     "Cannot get the clk dmc_clk\n");
+
+	data->edev = devfreq_event_get_edev_by_phandle(dev, "devfreq-events", 0);
+	if (IS_ERR(data->edev))
+		return -EPROBE_DEFER;
+
+	ret = devfreq_event_enable_edev(data->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable devfreq-event devices\n");
+		return ret;
+	}
+
+	rk3399_dmcfreq_of_props(data, np);
+
+	node = of_parse_phandle(np, "rockchip,pmu", 0);
+	if (!node)
+		goto no_pmu;
+
+	data->regmap_pmu = syscon_node_to_regmap(node);
+	of_node_put(node);
+	if (IS_ERR(data->regmap_pmu)) {
+		ret = PTR_ERR(data->regmap_pmu);
+		goto err_edev;
+	}
+
+	regmap_read(data->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
+	ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
+		    RK3399_PMUGRF_DDRTYPE_MASK;
+
+	switch (ddr_type) {
+	case RK3399_PMUGRF_DDRTYPE_DDR3:
+		data->odt_dis_freq = data->ddr3_odt_dis_freq;
+		break;
+	case RK3399_PMUGRF_DDRTYPE_LPDDR3:
+		data->odt_dis_freq = data->lpddr3_odt_dis_freq;
+		break;
+	case RK3399_PMUGRF_DDRTYPE_LPDDR4:
+		data->odt_dis_freq = data->lpddr4_odt_dis_freq;
+		break;
+	default:
+		ret = -EINVAL;
+		goto err_edev;
+	}
+
+no_pmu:
+	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0,
+		      ROCKCHIP_SIP_CONFIG_DRAM_INIT,
+		      0, 0, 0, 0, &res);
+
+	/*
+	 * We add a devfreq driver to our parent since it has a device tree node
+	 * with operating points.
+	 */
+	if (devm_pm_opp_of_add_table(dev)) {
+		dev_err(dev, "Invalid operating-points in device tree.\n");
+		ret = -EINVAL;
+		goto err_edev;
+	}
+
+	data->ondemand_data.upthreshold = 25;
+	data->ondemand_data.downdifferential = 15;
+
+	data->rate = clk_get_rate(data->dmc_clk);
+
+	opp = devfreq_recommended_opp(dev, &data->rate, 0);
+	if (IS_ERR(opp)) {
+		ret = PTR_ERR(opp);
+		goto err_edev;
+	}
+
+	data->rate = dev_pm_opp_get_freq(opp);
+	data->volt = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+
+	data->profile = (struct devfreq_dev_profile) {
+		.polling_ms	= 200,
+		.target		= rk3399_dmcfreq_target,
+		.get_dev_status	= rk3399_dmcfreq_get_dev_status,
+		.get_cur_freq	= rk3399_dmcfreq_get_cur_freq,
+		.initial_freq	= data->rate,
+	};
+
+	data->devfreq = devm_devfreq_add_device(dev,
+					   &data->profile,
+					   DEVFREQ_GOV_SIMPLE_ONDEMAND,
+					   &data->ondemand_data);
+	if (IS_ERR(data->devfreq)) {
+		ret = PTR_ERR(data->devfreq);
+		goto err_edev;
+	}
+
+	devm_devfreq_register_opp_notifier(dev, data->devfreq);
+
+	data->dev = dev;
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+
+err_edev:
+	devfreq_event_disable_edev(data->edev);
+
+	return ret;
+}
+
+static int rk3399_dmcfreq_remove(struct platform_device *pdev)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(&pdev->dev);
+
+	devfreq_event_disable_edev(dmcfreq->edev);
+
+	return 0;
+}
+
+static const struct of_device_id rk3399dmc_devfreq_of_match[] = {
+	{ .compatible = "rockchip,rk3399-dmc" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rk3399dmc_devfreq_of_match);
+
+static struct platform_driver rk3399_dmcfreq_driver = {
+	.probe	= rk3399_dmcfreq_probe,
+	.remove = rk3399_dmcfreq_remove,
+	.driver = {
+		.name	= "rk3399-dmc-freq",
+		.pm	= &rk3399_dmcfreq_pm,
+		.of_match_table = rk3399dmc_devfreq_of_match,
+	},
+};
+module_platform_driver(rk3399_dmcfreq_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
+MODULE_DESCRIPTION("RK3399 dmcfreq driver with devfreq framework");
diff --git a/drivers/devfreq/sun8i-a33-mbus.c b/drivers/devfreq/sun8i-a33-mbus.c
new file mode 100644
index 000000000..13d322131
--- /dev/null
+++ b/drivers/devfreq/sun8i-a33-mbus.c
@@ -0,0 +1,511 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright (C) 2020-2021 Samuel Holland <samuel@sholland.org>
+//
+
+#include <linux/clk.h>
+#include <linux/devfreq.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define MBUS_CR				0x0000
+#define MBUS_CR_GET_DRAM_TYPE(x)	(((x) >> 16) & 0x7)
+#define MBUS_CR_DRAM_TYPE_DDR2		2
+#define MBUS_CR_DRAM_TYPE_DDR3		3
+#define MBUS_CR_DRAM_TYPE_DDR4		4
+#define MBUS_CR_DRAM_TYPE_LPDDR2	6
+#define MBUS_CR_DRAM_TYPE_LPDDR3	7
+
+#define MBUS_TMR			0x000c
+#define MBUS_TMR_PERIOD(x)		((x) - 1)
+
+#define MBUS_PMU_CFG			0x009c
+#define MBUS_PMU_CFG_PERIOD(x)		(((x) - 1) << 16)
+#define MBUS_PMU_CFG_UNIT		(0x3 << 1)
+#define MBUS_PMU_CFG_UNIT_B		(0x0 << 1)
+#define MBUS_PMU_CFG_UNIT_KB		(0x1 << 1)
+#define MBUS_PMU_CFG_UNIT_MB		(0x2 << 1)
+#define MBUS_PMU_CFG_ENABLE		(0x1 << 0)
+
+#define MBUS_PMU_BWCR(n)		(0x00a0 + (0x04 * (n)))
+
+#define MBUS_TOTAL_BWCR			MBUS_PMU_BWCR(5)
+#define MBUS_TOTAL_BWCR_H616		MBUS_PMU_BWCR(13)
+
+#define MBUS_MDFSCR			0x0100
+#define MBUS_MDFSCR_BUFFER_TIMING	(0x1 << 15)
+#define MBUS_MDFSCR_PAD_HOLD		(0x1 << 13)
+#define MBUS_MDFSCR_BYPASS		(0x1 << 4)
+#define MBUS_MDFSCR_MODE		(0x1 << 1)
+#define MBUS_MDFSCR_MODE_DFS		(0x0 << 1)
+#define MBUS_MDFSCR_MODE_CFS		(0x1 << 1)
+#define MBUS_MDFSCR_START		(0x1 << 0)
+
+#define MBUS_MDFSMRMR			0x0108
+
+#define DRAM_PWRCTL			0x0004
+#define DRAM_PWRCTL_SELFREF_EN		(0x1 << 0)
+
+#define DRAM_RFSHTMG			0x0090
+#define DRAM_RFSHTMG_TREFI(x)		((x) << 16)
+#define DRAM_RFSHTMG_TRFC(x)		((x) << 0)
+
+#define DRAM_VTFCR			0x00b8
+#define DRAM_VTFCR_VTF_ENABLE		(0x3 << 8)
+
+#define DRAM_ODTMAP			0x0120
+
+#define DRAM_DX_MAX			4
+
+#define DRAM_DXnGCR0(n)			(0x0344 + 0x80 * (n))
+#define DRAM_DXnGCR0_DXODT		(0x3 << 4)
+#define DRAM_DXnGCR0_DXODT_DYNAMIC	(0x0 << 4)
+#define DRAM_DXnGCR0_DXODT_ENABLED	(0x1 << 4)
+#define DRAM_DXnGCR0_DXODT_DISABLED	(0x2 << 4)
+#define DRAM_DXnGCR0_DXEN		(0x1 << 0)
+
+struct sun8i_a33_mbus_variant {
+	u32					min_dram_divider;
+	u32					max_dram_divider;
+	u32					odt_freq_mhz;
+};
+
+struct sun8i_a33_mbus {
+	const struct sun8i_a33_mbus_variant	*variant;
+	void __iomem				*reg_dram;
+	void __iomem				*reg_mbus;
+	struct clk				*clk_bus;
+	struct clk				*clk_dram;
+	struct clk				*clk_mbus;
+	struct devfreq				*devfreq_dram;
+	struct devfreq_simple_ondemand_data	gov_data;
+	struct devfreq_dev_profile		profile;
+	u32					data_width;
+	u32					nominal_bw;
+	u32					odtmap;
+	u32					tREFI_ns;
+	u32					tRFC_ns;
+	unsigned long				freq_table[];
+};
+
+/*
+ * The unit for this value is (MBUS clock cycles / MBUS_TMR_PERIOD). When
+ * MBUS_TMR_PERIOD is programmed to match the MBUS clock frequency in MHz, as
+ * it is during DRAM init and during probe, the resulting unit is microseconds.
+ */
+static int pmu_period = 50000;
+module_param(pmu_period, int, 0644);
+MODULE_PARM_DESC(pmu_period, "Bandwidth measurement period (microseconds)");
+
+static u32 sun8i_a33_mbus_get_peak_bw(struct sun8i_a33_mbus *priv)
+{
+	/* Returns the peak transfer (in KiB) during any single PMU period. */
+	return readl_relaxed(priv->reg_mbus + MBUS_TOTAL_BWCR);
+}
+
+static void sun8i_a33_mbus_restart_pmu_counters(struct sun8i_a33_mbus *priv)
+{
+	u32 pmu_cfg = MBUS_PMU_CFG_PERIOD(pmu_period) | MBUS_PMU_CFG_UNIT_KB;
+
+	/* All PMU counters are cleared on a disable->enable transition. */
+	writel_relaxed(pmu_cfg,
+		       priv->reg_mbus + MBUS_PMU_CFG);
+	writel_relaxed(pmu_cfg | MBUS_PMU_CFG_ENABLE,
+		       priv->reg_mbus + MBUS_PMU_CFG);
+
+}
+
+static void sun8i_a33_mbus_update_nominal_bw(struct sun8i_a33_mbus *priv,
+					     u32 ddr_freq_mhz)
+{
+	/*
+	 * Nominal bandwidth (KiB per PMU period):
+	 *
+	 *   DDR transfers   microseconds     KiB
+	 *   ------------- * ------------ * --------
+	 *    microsecond     PMU period    transfer
+	 */
+	priv->nominal_bw = ddr_freq_mhz * pmu_period * priv->data_width / 1024;
+}
+
+static int sun8i_a33_mbus_set_dram_freq(struct sun8i_a33_mbus *priv,
+					unsigned long freq)
+{
+	u32  ddr_freq_mhz = freq / USEC_PER_SEC; /* DDR */
+	u32 dram_freq_mhz =    ddr_freq_mhz / 2; /* SDR */
+	u32 mctl_freq_mhz =   dram_freq_mhz / 2; /* HDR */
+	u32 dxodt, mdfscr, pwrctl, vtfcr;
+	u32 i, tREFI_32ck, tRFC_ck;
+	int ret;
+
+	/* The rate change is not effective until the MDFS process runs. */
+	ret = clk_set_rate(priv->clk_dram, freq);
+	if (ret)
+		return ret;
+
+	/* Disable automatic self-refesh and VTF before starting MDFS. */
+	pwrctl = readl_relaxed(priv->reg_dram + DRAM_PWRCTL) &
+		 ~DRAM_PWRCTL_SELFREF_EN;
+	writel_relaxed(pwrctl, priv->reg_dram + DRAM_PWRCTL);
+	vtfcr = readl_relaxed(priv->reg_dram + DRAM_VTFCR);
+	writel_relaxed(vtfcr & ~DRAM_VTFCR_VTF_ENABLE,
+		       priv->reg_dram + DRAM_VTFCR);
+
+	/* Set up MDFS and enable double buffering for timing registers. */
+	mdfscr = MBUS_MDFSCR_MODE_DFS |
+		 MBUS_MDFSCR_BYPASS |
+		 MBUS_MDFSCR_PAD_HOLD |
+		 MBUS_MDFSCR_BUFFER_TIMING;
+	writel(mdfscr, priv->reg_mbus + MBUS_MDFSCR);
+
+	/* Update the buffered copy of RFSHTMG. */
+	tREFI_32ck = priv->tREFI_ns * mctl_freq_mhz / 1000 / 32;
+	tRFC_ck = DIV_ROUND_UP(priv->tRFC_ns * mctl_freq_mhz, 1000);
+	writel(DRAM_RFSHTMG_TREFI(tREFI_32ck) | DRAM_RFSHTMG_TRFC(tRFC_ck),
+	       priv->reg_dram + DRAM_RFSHTMG);
+
+	/* Enable ODT if needed, or disable it to save power. */
+	if (priv->odtmap && dram_freq_mhz > priv->variant->odt_freq_mhz) {
+		dxodt = DRAM_DXnGCR0_DXODT_DYNAMIC;
+		writel(priv->odtmap, priv->reg_dram + DRAM_ODTMAP);
+	} else {
+		dxodt = DRAM_DXnGCR0_DXODT_DISABLED;
+		writel(0, priv->reg_dram + DRAM_ODTMAP);
+	}
+	for (i = 0; i < DRAM_DX_MAX; ++i) {
+		void __iomem *reg = priv->reg_dram + DRAM_DXnGCR0(i);
+
+		writel((readl(reg) & ~DRAM_DXnGCR0_DXODT) | dxodt, reg);
+	}
+
+	dev_dbg(priv->devfreq_dram->dev.parent,
+		"Setting DRAM to %u MHz, tREFI=%u, tRFC=%u, ODT=%s\n",
+		dram_freq_mhz, tREFI_32ck, tRFC_ck,
+		dxodt == DRAM_DXnGCR0_DXODT_DYNAMIC ? "dynamic" : "disabled");
+
+	/* Trigger hardware MDFS. */
+	writel(mdfscr | MBUS_MDFSCR_START, priv->reg_mbus + MBUS_MDFSCR);
+	ret = readl_poll_timeout_atomic(priv->reg_mbus + MBUS_MDFSCR, mdfscr,
+					!(mdfscr & MBUS_MDFSCR_START), 10, 1000);
+	if (ret)
+		return ret;
+
+	/* Disable double buffering. */
+	writel(0, priv->reg_mbus + MBUS_MDFSCR);
+
+	/* Restore VTF configuration. */
+	writel_relaxed(vtfcr, priv->reg_dram + DRAM_VTFCR);
+
+	/* Enable automatic self-refresh at the lowest frequency only. */
+	if (freq == priv->freq_table[0])
+		pwrctl |= DRAM_PWRCTL_SELFREF_EN;
+	writel_relaxed(pwrctl, priv->reg_dram + DRAM_PWRCTL);
+
+	sun8i_a33_mbus_restart_pmu_counters(priv);
+	sun8i_a33_mbus_update_nominal_bw(priv, ddr_freq_mhz);
+
+	return 0;
+}
+
+static int sun8i_a33_mbus_set_dram_target(struct device *dev,
+					  unsigned long *freq, u32 flags)
+{
+	struct sun8i_a33_mbus *priv = dev_get_drvdata(dev);
+	struct devfreq *devfreq = priv->devfreq_dram;
+	struct dev_pm_opp *opp;
+	int ret;
+
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp))
+		return PTR_ERR(opp);
+
+	dev_pm_opp_put(opp);
+
+	if (*freq == devfreq->previous_freq)
+		return 0;
+
+	ret = sun8i_a33_mbus_set_dram_freq(priv, *freq);
+	if (ret) {
+		dev_warn(dev, "failed to set DRAM frequency: %d\n", ret);
+		*freq = devfreq->previous_freq;
+	}
+
+	return ret;
+}
+
+static int sun8i_a33_mbus_get_dram_status(struct device *dev,
+					  struct devfreq_dev_status *stat)
+{
+	struct sun8i_a33_mbus *priv = dev_get_drvdata(dev);
+
+	stat->busy_time		= sun8i_a33_mbus_get_peak_bw(priv);
+	stat->total_time	= priv->nominal_bw;
+	stat->current_frequency	= priv->devfreq_dram->previous_freq;
+
+	sun8i_a33_mbus_restart_pmu_counters(priv);
+
+	dev_dbg(dev, "Using %lu/%lu (%lu%%) at %lu MHz\n",
+		stat->busy_time, stat->total_time,
+		DIV_ROUND_CLOSEST(stat->busy_time * 100, stat->total_time),
+		stat->current_frequency / USEC_PER_SEC);
+
+	return 0;
+}
+
+static int sun8i_a33_mbus_hw_init(struct device *dev,
+				  struct sun8i_a33_mbus *priv,
+				  unsigned long ddr_freq)
+{
+	u32 i, mbus_cr, mbus_freq_mhz;
+
+	/* Choose tREFI and tRFC to match the configured DRAM type. */
+	mbus_cr = readl_relaxed(priv->reg_mbus + MBUS_CR);
+	switch (MBUS_CR_GET_DRAM_TYPE(mbus_cr)) {
+	case MBUS_CR_DRAM_TYPE_DDR2:
+	case MBUS_CR_DRAM_TYPE_DDR3:
+	case MBUS_CR_DRAM_TYPE_DDR4:
+		priv->tREFI_ns = 7800;
+		priv->tRFC_ns = 350;
+		break;
+	case MBUS_CR_DRAM_TYPE_LPDDR2:
+	case MBUS_CR_DRAM_TYPE_LPDDR3:
+		priv->tREFI_ns = 3900;
+		priv->tRFC_ns = 210;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Save ODTMAP so it can be restored when raising the frequency. */
+	priv->odtmap = readl_relaxed(priv->reg_dram + DRAM_ODTMAP);
+
+	/* Compute the DRAM data bus width by counting enabled DATx8 blocks. */
+	for (i = 0; i < DRAM_DX_MAX; ++i) {
+		void __iomem *reg = priv->reg_dram + DRAM_DXnGCR0(i);
+
+		if (!(readl_relaxed(reg) & DRAM_DXnGCR0_DXEN))
+			break;
+	}
+	priv->data_width = i;
+
+	dev_dbg(dev, "Detected %u-bit %sDDRx with%s ODT\n",
+		priv->data_width * 8,
+		MBUS_CR_GET_DRAM_TYPE(mbus_cr) > 4 ? "LP" : "",
+		priv->odtmap ? "" : "out");
+
+	/* Program MBUS_TMR such that the PMU period unit is microseconds. */
+	mbus_freq_mhz = clk_get_rate(priv->clk_mbus) / USEC_PER_SEC;
+	writel_relaxed(MBUS_TMR_PERIOD(mbus_freq_mhz),
+		       priv->reg_mbus + MBUS_TMR);
+
+	/* "Master Ready Mask Register" bits must be set or MDFS will block. */
+	writel_relaxed(0xffffffff, priv->reg_mbus + MBUS_MDFSMRMR);
+
+	sun8i_a33_mbus_restart_pmu_counters(priv);
+	sun8i_a33_mbus_update_nominal_bw(priv, ddr_freq / USEC_PER_SEC);
+
+	return 0;
+}
+
+static int __maybe_unused sun8i_a33_mbus_suspend(struct device *dev)
+{
+	struct sun8i_a33_mbus *priv = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(priv->clk_bus);
+
+	return 0;
+}
+
+static int __maybe_unused sun8i_a33_mbus_resume(struct device *dev)
+{
+	struct sun8i_a33_mbus *priv = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(priv->clk_bus);
+}
+
+static int sun8i_a33_mbus_probe(struct platform_device *pdev)
+{
+	const struct sun8i_a33_mbus_variant *variant;
+	struct device *dev = &pdev->dev;
+	struct sun8i_a33_mbus *priv;
+	unsigned long base_freq;
+	unsigned int max_state;
+	const char *err;
+	int i, ret;
+
+	variant = device_get_match_data(dev);
+	if (!variant)
+		return -EINVAL;
+
+	max_state = variant->max_dram_divider - variant->min_dram_divider + 1;
+
+	priv = devm_kzalloc(dev, struct_size(priv, freq_table, max_state), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	priv->variant = variant;
+
+	priv->reg_dram = devm_platform_ioremap_resource_byname(pdev, "dram");
+	if (IS_ERR(priv->reg_dram))
+		return PTR_ERR(priv->reg_dram);
+
+	priv->reg_mbus = devm_platform_ioremap_resource_byname(pdev, "mbus");
+	if (IS_ERR(priv->reg_mbus))
+		return PTR_ERR(priv->reg_mbus);
+
+	priv->clk_bus = devm_clk_get(dev, "bus");
+	if (IS_ERR(priv->clk_bus))
+		return dev_err_probe(dev, PTR_ERR(priv->clk_bus),
+				     "failed to get bus clock\n");
+
+	priv->clk_dram = devm_clk_get(dev, "dram");
+	if (IS_ERR(priv->clk_dram))
+		return dev_err_probe(dev, PTR_ERR(priv->clk_dram),
+				     "failed to get dram clock\n");
+
+	priv->clk_mbus = devm_clk_get(dev, "mbus");
+	if (IS_ERR(priv->clk_mbus))
+		return dev_err_probe(dev, PTR_ERR(priv->clk_mbus),
+				     "failed to get mbus clock\n");
+
+	ret = clk_prepare_enable(priv->clk_bus);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to enable bus clock\n");
+
+	/* Lock the DRAM clock rate to keep priv->nominal_bw in sync. */
+	ret = clk_rate_exclusive_get(priv->clk_dram);
+	if (ret) {
+		err = "failed to lock dram clock rate\n";
+		goto err_disable_bus;
+	}
+
+	/* Lock the MBUS clock rate to keep MBUS_TMR_PERIOD in sync. */
+	ret = clk_rate_exclusive_get(priv->clk_mbus);
+	if (ret) {
+		err = "failed to lock mbus clock rate\n";
+		goto err_unlock_dram;
+	}
+
+	priv->gov_data.upthreshold	= 10;
+	priv->gov_data.downdifferential	=  5;
+
+	priv->profile.initial_freq	= clk_get_rate(priv->clk_dram);
+	priv->profile.polling_ms	= 1000;
+	priv->profile.target		= sun8i_a33_mbus_set_dram_target;
+	priv->profile.get_dev_status	= sun8i_a33_mbus_get_dram_status;
+	priv->profile.freq_table	= priv->freq_table;
+	priv->profile.max_state		= max_state;
+
+	ret = devm_pm_opp_set_clkname(dev, "dram");
+	if (ret) {
+		err = "failed to add OPP table\n";
+		goto err_unlock_mbus;
+	}
+
+	base_freq = clk_get_rate(clk_get_parent(priv->clk_dram));
+	for (i = 0; i < max_state; ++i) {
+		unsigned int div = variant->max_dram_divider - i;
+
+		priv->freq_table[i] = base_freq / div;
+
+		ret = dev_pm_opp_add(dev, priv->freq_table[i], 0);
+		if (ret) {
+			err = "failed to add OPPs\n";
+			goto err_remove_opps;
+		}
+	}
+
+	ret = sun8i_a33_mbus_hw_init(dev, priv, priv->profile.initial_freq);
+	if (ret) {
+		err = "failed to init hardware\n";
+		goto err_remove_opps;
+	}
+
+	priv->devfreq_dram = devfreq_add_device(dev, &priv->profile,
+						DEVFREQ_GOV_SIMPLE_ONDEMAND,
+						&priv->gov_data);
+	if (IS_ERR(priv->devfreq_dram)) {
+		ret = PTR_ERR(priv->devfreq_dram);
+		err = "failed to add devfreq device\n";
+		goto err_remove_opps;
+	}
+
+	/*
+	 * This must be set manually after registering the devfreq device,
+	 * because there is no way to select a dynamic OPP as the suspend OPP.
+	 */
+	priv->devfreq_dram->suspend_freq = priv->freq_table[0];
+
+	return 0;
+
+err_remove_opps:
+	dev_pm_opp_remove_all_dynamic(dev);
+err_unlock_mbus:
+	clk_rate_exclusive_put(priv->clk_mbus);
+err_unlock_dram:
+	clk_rate_exclusive_put(priv->clk_dram);
+err_disable_bus:
+	clk_disable_unprepare(priv->clk_bus);
+
+	return dev_err_probe(dev, ret, err);
+}
+
+static int sun8i_a33_mbus_remove(struct platform_device *pdev)
+{
+	struct sun8i_a33_mbus *priv = platform_get_drvdata(pdev);
+	unsigned long initial_freq = priv->profile.initial_freq;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	devfreq_remove_device(priv->devfreq_dram);
+
+	ret = sun8i_a33_mbus_set_dram_freq(priv, initial_freq);
+	if (ret)
+		dev_warn(dev, "failed to restore DRAM frequency: %d\n", ret);
+
+	dev_pm_opp_remove_all_dynamic(dev);
+	clk_rate_exclusive_put(priv->clk_mbus);
+	clk_rate_exclusive_put(priv->clk_dram);
+	clk_disable_unprepare(priv->clk_bus);
+
+	return 0;
+}
+
+static const struct sun8i_a33_mbus_variant sun50i_a64_mbus = {
+	.min_dram_divider	= 1,
+	.max_dram_divider	= 4,
+	.odt_freq_mhz		= 400,
+};
+
+static const struct of_device_id sun8i_a33_mbus_of_match[] = {
+	{ .compatible = "allwinner,sun50i-a64-mbus", .data = &sun50i_a64_mbus },
+	{ .compatible = "allwinner,sun50i-h5-mbus", .data = &sun50i_a64_mbus },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sun8i_a33_mbus_of_match);
+
+static SIMPLE_DEV_PM_OPS(sun8i_a33_mbus_pm_ops,
+			 sun8i_a33_mbus_suspend, sun8i_a33_mbus_resume);
+
+static struct platform_driver sun8i_a33_mbus_driver = {
+	.probe	= sun8i_a33_mbus_probe,
+	.remove	= sun8i_a33_mbus_remove,
+	.driver	= {
+		.name		= "sun8i-a33-mbus",
+		.of_match_table	= sun8i_a33_mbus_of_match,
+		.pm		= pm_ptr(&sun8i_a33_mbus_pm_ops),
+	},
+};
+module_platform_driver(sun8i_a33_mbus_driver);
+
+MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
+MODULE_DESCRIPTION("Allwinner sun8i/sun50i MBUS DEVFREQ Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
new file mode 100644
index 000000000..503376b89
--- /dev/null
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -0,0 +1,983 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * A devfreq driver for NVIDIA Tegra SoCs
+ *
+ * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
+ * Copyright (C) 2014 Google, Inc
+ */
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/devfreq.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/reset.h>
+#include <linux/workqueue.h>
+
+#include <soc/tegra/fuse.h>
+
+#include "governor.h"
+
+#define ACTMON_GLB_STATUS					0x0
+#define ACTMON_GLB_PERIOD_CTRL					0x4
+
+#define ACTMON_DEV_CTRL						0x0
+#define ACTMON_DEV_CTRL_K_VAL_SHIFT				10
+#define ACTMON_DEV_CTRL_ENB_PERIODIC				BIT(18)
+#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN			BIT(20)
+#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN			BIT(21)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT	23
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT	26
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN		BIT(29)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN		BIT(30)
+#define ACTMON_DEV_CTRL_ENB					BIT(31)
+
+#define ACTMON_DEV_CTRL_STOP					0x00000000
+
+#define ACTMON_DEV_UPPER_WMARK					0x4
+#define ACTMON_DEV_LOWER_WMARK					0x8
+#define ACTMON_DEV_INIT_AVG					0xc
+#define ACTMON_DEV_AVG_UPPER_WMARK				0x10
+#define ACTMON_DEV_AVG_LOWER_WMARK				0x14
+#define ACTMON_DEV_COUNT_WEIGHT					0x18
+#define ACTMON_DEV_AVG_COUNT					0x20
+#define ACTMON_DEV_INTR_STATUS					0x24
+
+#define ACTMON_INTR_STATUS_CLEAR				0xffffffff
+
+#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER			BIT(31)
+#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER			BIT(30)
+
+#define ACTMON_ABOVE_WMARK_WINDOW				1
+#define ACTMON_BELOW_WMARK_WINDOW				3
+#define ACTMON_BOOST_FREQ_STEP					16000
+
+/*
+ * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
+ * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
+ */
+#define ACTMON_AVERAGE_WINDOW_LOG2			6
+#define ACTMON_SAMPLING_PERIOD				12 /* ms */
+#define ACTMON_DEFAULT_AVG_BAND				6  /* 1/10 of % */
+
+#define KHZ							1000
+
+#define KHZ_MAX						(ULONG_MAX / KHZ)
+
+/* Assume that the bus is saturated if the utilization is 25% */
+#define BUS_SATURATION_RATIO					25
+
+/**
+ * struct tegra_devfreq_device_config - configuration specific to an ACTMON
+ * device
+ *
+ * Coefficients and thresholds are percentages unless otherwise noted
+ */
+struct tegra_devfreq_device_config {
+	u32		offset;
+	u32		irq_mask;
+
+	/* Factors applied to boost_freq every consecutive watermark breach */
+	unsigned int	boost_up_coeff;
+	unsigned int	boost_down_coeff;
+
+	/* Define the watermark bounds when applied to the current avg */
+	unsigned int	boost_up_threshold;
+	unsigned int	boost_down_threshold;
+
+	/*
+	 * Threshold of activity (cycles translated to kHz) below which the
+	 * CPU frequency isn't to be taken into account. This is to avoid
+	 * increasing the EMC frequency when the CPU is very busy but not
+	 * accessing the bus often.
+	 */
+	u32		avg_dependency_threshold;
+};
+
+enum tegra_actmon_device {
+	MCALL = 0,
+	MCCPU,
+};
+
+static const struct tegra_devfreq_device_config tegra124_device_configs[] = {
+	{
+		/* MCALL: All memory accesses (including from the CPUs) */
+		.offset = 0x1c0,
+		.irq_mask = 1 << 26,
+		.boost_up_coeff = 200,
+		.boost_down_coeff = 50,
+		.boost_up_threshold = 60,
+		.boost_down_threshold = 40,
+	},
+	{
+		/* MCCPU: memory accesses from the CPUs */
+		.offset = 0x200,
+		.irq_mask = 1 << 25,
+		.boost_up_coeff = 800,
+		.boost_down_coeff = 40,
+		.boost_up_threshold = 27,
+		.boost_down_threshold = 10,
+		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
+	},
+};
+
+static const struct tegra_devfreq_device_config tegra30_device_configs[] = {
+	{
+		/* MCALL: All memory accesses (including from the CPUs) */
+		.offset = 0x1c0,
+		.irq_mask = 1 << 26,
+		.boost_up_coeff = 200,
+		.boost_down_coeff = 50,
+		.boost_up_threshold = 20,
+		.boost_down_threshold = 10,
+	},
+	{
+		/* MCCPU: memory accesses from the CPUs */
+		.offset = 0x200,
+		.irq_mask = 1 << 25,
+		.boost_up_coeff = 800,
+		.boost_down_coeff = 40,
+		.boost_up_threshold = 27,
+		.boost_down_threshold = 10,
+		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
+	},
+};
+
+/**
+ * struct tegra_devfreq_device - state specific to an ACTMON device
+ *
+ * Frequencies are in kHz.
+ */
+struct tegra_devfreq_device {
+	const struct tegra_devfreq_device_config *config;
+	void __iomem *regs;
+
+	/* Average event count sampled in the last interrupt */
+	u32 avg_count;
+
+	/*
+	 * Extra frequency to increase the target by due to consecutive
+	 * watermark breaches.
+	 */
+	unsigned long boost_freq;
+
+	/* Optimal frequency calculated from the stats for this device */
+	unsigned long target_freq;
+};
+
+struct tegra_devfreq_soc_data {
+	const struct tegra_devfreq_device_config *configs;
+	/* Weight value for count measurements */
+	unsigned int count_weight;
+};
+
+struct tegra_devfreq {
+	struct devfreq		*devfreq;
+
+	struct reset_control	*reset;
+	struct clk		*clock;
+	void __iomem		*regs;
+
+	struct clk		*emc_clock;
+	unsigned long		max_freq;
+	unsigned long		cur_freq;
+	struct notifier_block	clk_rate_change_nb;
+
+	struct delayed_work	cpufreq_update_work;
+	struct notifier_block	cpu_rate_change_nb;
+
+	struct tegra_devfreq_device devices[2];
+
+	unsigned int		irq;
+
+	bool			started;
+
+	const struct tegra_devfreq_soc_data *soc;
+};
+
+struct tegra_actmon_emc_ratio {
+	unsigned long cpu_freq;
+	unsigned long emc_freq;
+};
+
+static const struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
+	{ 1400000,    KHZ_MAX },
+	{ 1200000,    750000 },
+	{ 1100000,    600000 },
+	{ 1000000,    500000 },
+	{  800000,    375000 },
+	{  500000,    200000 },
+	{  250000,    100000 },
+};
+
+static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
+{
+	return readl_relaxed(tegra->regs + offset);
+}
+
+static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
+{
+	writel_relaxed(val, tegra->regs + offset);
+}
+
+static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
+{
+	return readl_relaxed(dev->regs + offset);
+}
+
+static void device_writel(struct tegra_devfreq_device *dev, u32 val,
+			  u32 offset)
+{
+	writel_relaxed(val, dev->regs + offset);
+}
+
+static unsigned long do_percent(unsigned long long val, unsigned int pct)
+{
+	val = val * pct;
+	do_div(val, 100);
+
+	/*
+	 * High freq + high boosting percent + large polling interval are
+	 * resulting in integer overflow when watermarks are calculated.
+	 */
+	return min_t(u64, val, U32_MAX);
+}
+
+static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
+					   struct tegra_devfreq_device *dev)
+{
+	u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
+	u32 band = avg_band_freq * tegra->devfreq->profile->polling_ms;
+	u32 avg;
+
+	avg = min(dev->avg_count, U32_MAX - band);
+	device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
+
+	avg = max(dev->avg_count, band);
+	device_writel(dev, avg - band, ACTMON_DEV_AVG_LOWER_WMARK);
+}
+
+static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
+				       struct tegra_devfreq_device *dev)
+{
+	u32 val = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
+
+	device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
+		      ACTMON_DEV_UPPER_WMARK);
+
+	device_writel(dev, do_percent(val, dev->config->boost_down_threshold),
+		      ACTMON_DEV_LOWER_WMARK);
+}
+
+static void actmon_isr_device(struct tegra_devfreq *tegra,
+			      struct tegra_devfreq_device *dev)
+{
+	u32 intr_status, dev_ctrl;
+
+	dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
+	tegra_devfreq_update_avg_wmark(tegra, dev);
+
+	intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS);
+	dev_ctrl = device_readl(dev, ACTMON_DEV_CTRL);
+
+	if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
+		/*
+		 * new_boost = min(old_boost * up_coef + step, max_freq)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_up_coeff);
+		dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
+
+		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+
+		if (dev->boost_freq >= tegra->max_freq) {
+			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+			dev->boost_freq = tegra->max_freq;
+		}
+	} else if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
+		/*
+		 * new_boost = old_boost * down_coef
+		 * or 0 if (old_boost * down_coef < step / 2)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_down_coeff);
+
+		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+
+		if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
+			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+			dev->boost_freq = 0;
+		}
+	}
+
+	device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL);
+
+	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
+}
+
+static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
+					    unsigned long cpu_freq)
+{
+	unsigned int i;
+	const struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
+
+	for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
+		if (cpu_freq >= ratio->cpu_freq) {
+			if (ratio->emc_freq >= tegra->max_freq)
+				return tegra->max_freq;
+			else
+				return ratio->emc_freq;
+		}
+	}
+
+	return 0;
+}
+
+static unsigned long actmon_device_target_freq(struct tegra_devfreq *tegra,
+					       struct tegra_devfreq_device *dev)
+{
+	unsigned int avg_sustain_coef;
+	unsigned long target_freq;
+
+	target_freq = dev->avg_count / tegra->devfreq->profile->polling_ms;
+	avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
+	target_freq = do_percent(target_freq, avg_sustain_coef);
+
+	return target_freq;
+}
+
+static void actmon_update_target(struct tegra_devfreq *tegra,
+				 struct tegra_devfreq_device *dev)
+{
+	unsigned long cpu_freq = 0;
+	unsigned long static_cpu_emc_freq = 0;
+
+	dev->target_freq = actmon_device_target_freq(tegra, dev);
+
+	if (dev->config->avg_dependency_threshold &&
+	    dev->config->avg_dependency_threshold <= dev->target_freq) {
+		cpu_freq = cpufreq_quick_get(0);
+		static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
+
+		dev->target_freq += dev->boost_freq;
+		dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
+	} else {
+		dev->target_freq += dev->boost_freq;
+	}
+}
+
+static irqreturn_t actmon_thread_isr(int irq, void *data)
+{
+	struct tegra_devfreq *tegra = data;
+	bool handled = false;
+	unsigned int i;
+	u32 val;
+
+	mutex_lock(&tegra->devfreq->lock);
+
+	val = actmon_readl(tegra, ACTMON_GLB_STATUS);
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		if (val & tegra->devices[i].config->irq_mask) {
+			actmon_isr_device(tegra, tegra->devices + i);
+			handled = true;
+		}
+	}
+
+	if (handled)
+		update_devfreq(tegra->devfreq);
+
+	mutex_unlock(&tegra->devfreq->lock);
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int tegra_actmon_clk_notify_cb(struct notifier_block *nb,
+				      unsigned long action, void *ptr)
+{
+	struct clk_notifier_data *data = ptr;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	unsigned int i;
+
+	if (action != POST_RATE_CHANGE)
+		return NOTIFY_OK;
+
+	tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
+
+	tegra->cur_freq = data->new_rate / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = &tegra->devices[i];
+
+		tegra_devfreq_update_wmark(tegra, dev);
+	}
+
+	return NOTIFY_OK;
+}
+
+static void tegra_actmon_delayed_update(struct work_struct *work)
+{
+	struct tegra_devfreq *tegra = container_of(work, struct tegra_devfreq,
+						   cpufreq_update_work.work);
+
+	mutex_lock(&tegra->devfreq->lock);
+	update_devfreq(tegra->devfreq);
+	mutex_unlock(&tegra->devfreq->lock);
+}
+
+static unsigned long
+tegra_actmon_cpufreq_contribution(struct tegra_devfreq *tegra,
+				  unsigned int cpu_freq)
+{
+	struct tegra_devfreq_device *actmon_dev = &tegra->devices[MCCPU];
+	unsigned long static_cpu_emc_freq, dev_freq;
+
+	dev_freq = actmon_device_target_freq(tegra, actmon_dev);
+
+	/* check whether CPU's freq is taken into account at all */
+	if (dev_freq < actmon_dev->config->avg_dependency_threshold)
+		return 0;
+
+	static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
+
+	if (dev_freq + actmon_dev->boost_freq >= static_cpu_emc_freq)
+		return 0;
+
+	return static_cpu_emc_freq;
+}
+
+static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
+				      unsigned long action, void *ptr)
+{
+	struct cpufreq_freqs *freqs = ptr;
+	struct tegra_devfreq *tegra;
+	unsigned long old, new, delay;
+
+	if (action != CPUFREQ_POSTCHANGE)
+		return NOTIFY_OK;
+
+	tegra = container_of(nb, struct tegra_devfreq, cpu_rate_change_nb);
+
+	/*
+	 * Quickly check whether CPU frequency should be taken into account
+	 * at all, without blocking CPUFreq's core.
+	 */
+	if (mutex_trylock(&tegra->devfreq->lock)) {
+		old = tegra_actmon_cpufreq_contribution(tegra, freqs->old);
+		new = tegra_actmon_cpufreq_contribution(tegra, freqs->new);
+		mutex_unlock(&tegra->devfreq->lock);
+
+		/*
+		 * If CPU's frequency shouldn't be taken into account at
+		 * the moment, then there is no need to update the devfreq's
+		 * state because ISR will re-check CPU's frequency on the
+		 * next interrupt.
+		 */
+		if (old == new)
+			return NOTIFY_OK;
+	}
+
+	/*
+	 * CPUFreq driver should support CPUFREQ_ASYNC_NOTIFICATION in order
+	 * to allow asynchronous notifications. This means we can't block
+	 * here for too long, otherwise CPUFreq's core will complain with a
+	 * warning splat.
+	 */
+	delay = msecs_to_jiffies(ACTMON_SAMPLING_PERIOD);
+	schedule_delayed_work(&tegra->cpufreq_update_work, delay);
+
+	return NOTIFY_OK;
+}
+
+static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
+					  struct tegra_devfreq_device *dev)
+{
+	u32 val = 0;
+
+	/* reset boosting on governor's restart */
+	dev->boost_freq = 0;
+
+	dev->target_freq = tegra->cur_freq;
+
+	dev->avg_count = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
+	device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG);
+
+	tegra_devfreq_update_avg_wmark(tegra, dev);
+	tegra_devfreq_update_wmark(tegra, dev);
+
+	device_writel(dev, tegra->soc->count_weight, ACTMON_DEV_COUNT_WEIGHT);
+	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
+
+	val |= ACTMON_DEV_CTRL_ENB_PERIODIC;
+	val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
+		<< ACTMON_DEV_CTRL_K_VAL_SHIFT;
+	val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
+	val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
+	val |= ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_ENB;
+
+	device_writel(dev, val, ACTMON_DEV_CTRL);
+}
+
+static void tegra_actmon_stop_devices(struct tegra_devfreq *tegra)
+{
+	struct tegra_devfreq_device *dev = tegra->devices;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++, dev++) {
+		device_writel(dev, ACTMON_DEV_CTRL_STOP, ACTMON_DEV_CTRL);
+		device_writel(dev, ACTMON_INTR_STATUS_CLEAR,
+			      ACTMON_DEV_INTR_STATUS);
+	}
+}
+
+static int tegra_actmon_resume(struct tegra_devfreq *tegra)
+{
+	unsigned int i;
+	int err;
+
+	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+		return 0;
+
+	actmon_writel(tegra, tegra->devfreq->profile->polling_ms - 1,
+		      ACTMON_GLB_PERIOD_CTRL);
+
+	/*
+	 * CLK notifications are needed in order to reconfigure the upper
+	 * consecutive watermark in accordance to the actual clock rate
+	 * to avoid unnecessary upper interrupts.
+	 */
+	err = clk_notifier_register(tegra->emc_clock,
+				    &tegra->clk_rate_change_nb);
+	if (err) {
+		dev_err(tegra->devfreq->dev.parent,
+			"Failed to register rate change notifier\n");
+		return err;
+	}
+
+	tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
+		tegra_actmon_configure_device(tegra, &tegra->devices[i]);
+
+	/*
+	 * We are estimating CPU's memory bandwidth requirement based on
+	 * amount of memory accesses and system's load, judging by CPU's
+	 * frequency. We also don't want to receive events about CPU's
+	 * frequency transaction when governor is stopped, hence notifier
+	 * is registered dynamically.
+	 */
+	err = cpufreq_register_notifier(&tegra->cpu_rate_change_nb,
+					CPUFREQ_TRANSITION_NOTIFIER);
+	if (err) {
+		dev_err(tegra->devfreq->dev.parent,
+			"Failed to register rate change notifier: %d\n", err);
+		goto err_stop;
+	}
+
+	enable_irq(tegra->irq);
+
+	return 0;
+
+err_stop:
+	tegra_actmon_stop_devices(tegra);
+
+	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
+
+	return err;
+}
+
+static int tegra_actmon_start(struct tegra_devfreq *tegra)
+{
+	int ret = 0;
+
+	if (!tegra->started) {
+		tegra->started = true;
+
+		ret = tegra_actmon_resume(tegra);
+		if (ret)
+			tegra->started = false;
+	}
+
+	return ret;
+}
+
+static void tegra_actmon_pause(struct tegra_devfreq *tegra)
+{
+	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+		return;
+
+	disable_irq(tegra->irq);
+
+	cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
+				    CPUFREQ_TRANSITION_NOTIFIER);
+
+	cancel_delayed_work_sync(&tegra->cpufreq_update_work);
+
+	tegra_actmon_stop_devices(tegra);
+
+	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
+}
+
+static void tegra_actmon_stop(struct tegra_devfreq *tegra)
+{
+	tegra_actmon_pause(tegra);
+	tegra->started = false;
+}
+
+static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
+				u32 flags)
+{
+	struct dev_pm_opp *opp;
+	int ret;
+
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "Failed to find opp for %lu Hz\n", *freq);
+		return PTR_ERR(opp);
+	}
+
+	ret = dev_pm_opp_set_opp(dev, opp);
+	dev_pm_opp_put(opp);
+
+	return ret;
+}
+
+static int tegra_devfreq_get_dev_status(struct device *dev,
+					struct devfreq_dev_status *stat)
+{
+	struct tegra_devfreq *tegra = dev_get_drvdata(dev);
+	struct tegra_devfreq_device *actmon_dev;
+	unsigned long cur_freq;
+
+	cur_freq = READ_ONCE(tegra->cur_freq);
+
+	/* To be used by the tegra governor */
+	stat->private_data = tegra;
+
+	/* The below are to be used by the other governors */
+	stat->current_frequency = cur_freq * KHZ;
+
+	actmon_dev = &tegra->devices[MCALL];
+
+	/* Number of cycles spent on memory access */
+	stat->busy_time = device_readl(actmon_dev, ACTMON_DEV_AVG_COUNT);
+
+	/* The bus can be considered to be saturated way before 100% */
+	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
+
+	/* Number of cycles in a sampling period */
+	stat->total_time = tegra->devfreq->profile->polling_ms * cur_freq;
+
+	stat->busy_time = min(stat->busy_time, stat->total_time);
+
+	return 0;
+}
+
+static struct devfreq_dev_profile tegra_devfreq_profile = {
+	.polling_ms	= ACTMON_SAMPLING_PERIOD,
+	.target		= tegra_devfreq_target,
+	.get_dev_status	= tegra_devfreq_get_dev_status,
+	.is_cooling_device = true,
+};
+
+static int tegra_governor_get_target(struct devfreq *devfreq,
+				     unsigned long *freq)
+{
+	struct devfreq_dev_status *stat;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	unsigned long target_freq = 0;
+	unsigned int i;
+	int err;
+
+	err = devfreq_update_stats(devfreq);
+	if (err)
+		return err;
+
+	stat = &devfreq->last_status;
+
+	tegra = stat->private_data;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = &tegra->devices[i];
+
+		actmon_update_target(tegra, dev);
+
+		target_freq = max(target_freq, dev->target_freq);
+	}
+
+	/*
+	 * tegra-devfreq driver operates with KHz units, while OPP table
+	 * entries use Hz units. Hence we need to convert the units for the
+	 * devfreq core.
+	 */
+	*freq = target_freq * KHZ;
+
+	return 0;
+}
+
+static int tegra_governor_event_handler(struct devfreq *devfreq,
+					unsigned int event, void *data)
+{
+	struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
+	unsigned int *new_delay = data;
+	int ret = 0;
+
+	/*
+	 * Couple devfreq-device with the governor early because it is
+	 * needed at the moment of governor's start (used by ISR).
+	 */
+	tegra->devfreq = devfreq;
+
+	switch (event) {
+	case DEVFREQ_GOV_START:
+		devfreq_monitor_start(devfreq);
+		ret = tegra_actmon_start(tegra);
+		break;
+
+	case DEVFREQ_GOV_STOP:
+		tegra_actmon_stop(tegra);
+		devfreq_monitor_stop(devfreq);
+		break;
+
+	case DEVFREQ_GOV_UPDATE_INTERVAL:
+		/*
+		 * ACTMON hardware supports up to 256 milliseconds for the
+		 * sampling period.
+		 */
+		if (*new_delay > 256) {
+			ret = -EINVAL;
+			break;
+		}
+
+		tegra_actmon_pause(tegra);
+		devfreq_update_interval(devfreq, new_delay);
+		ret = tegra_actmon_resume(tegra);
+		break;
+
+	case DEVFREQ_GOV_SUSPEND:
+		tegra_actmon_stop(tegra);
+		devfreq_monitor_suspend(devfreq);
+		break;
+
+	case DEVFREQ_GOV_RESUME:
+		devfreq_monitor_resume(devfreq);
+		ret = tegra_actmon_start(tegra);
+		break;
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor tegra_devfreq_governor = {
+	.name = "tegra_actmon",
+	.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL,
+	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE
+		| DEVFREQ_GOV_FLAG_IRQ_DRIVEN,
+	.get_target_freq = tegra_governor_get_target,
+	.event_handler = tegra_governor_event_handler,
+};
+
+static void devm_tegra_devfreq_deinit_hw(void *data)
+{
+	struct tegra_devfreq *tegra = data;
+
+	reset_control_reset(tegra->reset);
+	clk_disable_unprepare(tegra->clock);
+}
+
+static int devm_tegra_devfreq_init_hw(struct device *dev,
+				      struct tegra_devfreq *tegra)
+{
+	int err;
+
+	err = clk_prepare_enable(tegra->clock);
+	if (err) {
+		dev_err(dev, "Failed to prepare and enable ACTMON clock\n");
+		return err;
+	}
+
+	err = devm_add_action_or_reset(dev, devm_tegra_devfreq_deinit_hw,
+				       tegra);
+	if (err)
+		return err;
+
+	err = reset_control_reset(tegra->reset);
+	if (err) {
+		dev_err(dev, "Failed to reset hardware: %d\n", err);
+		return err;
+	}
+
+	return err;
+}
+
+static int tegra_devfreq_config_clks_nop(struct device *dev,
+					 struct opp_table *opp_table,
+					 struct dev_pm_opp *opp, void *data,
+					 bool scaling_down)
+{
+	/* We want to skip clk configuration via dev_pm_opp_set_opp() */
+	return 0;
+}
+
+static int tegra_devfreq_probe(struct platform_device *pdev)
+{
+	u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+	struct tegra_devfreq_device *dev;
+	struct tegra_devfreq *tegra;
+	struct devfreq *devfreq;
+	unsigned int i;
+	long rate;
+	int err;
+	const char *clk_names[] = { "actmon", NULL };
+	struct dev_pm_opp_config config = {
+		.supported_hw = &hw_version,
+		.supported_hw_count = 1,
+		.clk_names = clk_names,
+		.config_clks = tegra_devfreq_config_clks_nop,
+	};
+
+	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
+	if (!tegra)
+		return -ENOMEM;
+
+	tegra->soc = of_device_get_match_data(&pdev->dev);
+
+	tegra->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tegra->regs))
+		return PTR_ERR(tegra->regs);
+
+	tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->reset)) {
+		dev_err(&pdev->dev, "Failed to get reset\n");
+		return PTR_ERR(tegra->reset);
+	}
+
+	tegra->clock = devm_clk_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->clock)) {
+		dev_err(&pdev->dev, "Failed to get actmon clock\n");
+		return PTR_ERR(tegra->clock);
+	}
+
+	tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
+	if (IS_ERR(tegra->emc_clock))
+		return dev_err_probe(&pdev->dev, PTR_ERR(tegra->emc_clock),
+				     "Failed to get emc clock\n");
+
+	err = platform_get_irq(pdev, 0);
+	if (err < 0)
+		return err;
+
+	tegra->irq = err;
+
+	irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
+
+	err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
+					actmon_thread_isr, IRQF_ONESHOT,
+					"tegra-devfreq", tegra);
+	if (err) {
+		dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
+		return err;
+	}
+
+	err = devm_pm_opp_set_config(&pdev->dev, &config);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to set OPP config: %d\n", err);
+		return err;
+	}
+
+	err = devm_pm_opp_of_add_table_indexed(&pdev->dev, 0);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add OPP table: %d\n", err);
+		return err;
+	}
+
+	err = devm_tegra_devfreq_init_hw(&pdev->dev, tegra);
+	if (err)
+		return err;
+
+	rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
+	if (rate <= 0) {
+		dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate);
+		return rate ?: -EINVAL;
+	}
+
+	tegra->max_freq = rate / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = tegra->devices + i;
+		dev->config = tegra->soc->configs + i;
+		dev->regs = tegra->regs + dev->config->offset;
+	}
+
+	platform_set_drvdata(pdev, tegra);
+
+	tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb;
+	tegra->cpu_rate_change_nb.notifier_call = tegra_actmon_cpu_notify_cb;
+
+	INIT_DELAYED_WORK(&tegra->cpufreq_update_work,
+			  tegra_actmon_delayed_update);
+
+	err = devm_devfreq_add_governor(&pdev->dev, &tegra_devfreq_governor);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add governor: %d\n", err);
+		return err;
+	}
+
+	tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
+
+	devfreq = devm_devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
+					  "tegra_actmon", NULL);
+	if (IS_ERR(devfreq)) {
+		dev_err(&pdev->dev, "Failed to add device: %pe\n", devfreq);
+		return PTR_ERR(devfreq);
+	}
+
+	return 0;
+}
+
+static const struct tegra_devfreq_soc_data tegra124_soc = {
+	.configs = tegra124_device_configs,
+
+	/*
+	 * Activity counter is incremented every 256 memory transactions,
+	 * and each transaction takes 4 EMC clocks.
+	 */
+	.count_weight = 4 * 256,
+};
+
+static const struct tegra_devfreq_soc_data tegra30_soc = {
+	.configs = tegra30_device_configs,
+	.count_weight = 2 * 256,
+};
+
+static const struct of_device_id tegra_devfreq_of_match[] = {
+	{ .compatible = "nvidia,tegra30-actmon",  .data = &tegra30_soc, },
+	{ .compatible = "nvidia,tegra124-actmon", .data = &tegra124_soc, },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
+
+static struct platform_driver tegra_devfreq_driver = {
+	.probe	= tegra_devfreq_probe,
+	.driver = {
+		.name = "tegra-devfreq",
+		.of_match_table = tegra_devfreq_of_match,
+	},
+};
+module_platform_driver(tegra_devfreq_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Tegra devfreq driver");
+MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");