Adding upstream version 6.1.76.upstream/6.1.76upstream

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

1 files changed, 1621 insertions, 0 deletions

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
new file mode 100644
index 000000000..605d68673
--- /dev/null
+++ b/drivers/opp/of.c
@@ -0,0 +1,1621 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic OPP OF helpers
+ *
+ * Copyright (C) 2009-2010 Texas Instruments Incorporated.
+ *	Nishanth Menon
+ *	Romit Dasgupta
+ *	Kevin Hilman
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpu.h>
+#include <linux/errno.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/energy_model.h>
+
+#include "opp.h"
+
+/*
+ * Returns opp descriptor node for a device node, caller must
+ * do of_node_put().
+ */
+static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
+						     int index)
+{
+	/* "operating-points-v2" can be an array for power domain providers */
+	return of_parse_phandle(np, "operating-points-v2", index);
+}
+
+/* Returns opp descriptor node for a device, caller must do of_node_put() */
+struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
+{
+	return _opp_of_get_opp_desc_node(dev->of_node, 0);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);
+
+struct opp_table *_managed_opp(struct device *dev, int index)
+{
+	struct opp_table *opp_table, *managed_table = NULL;
+	struct device_node *np;
+
+	np = _opp_of_get_opp_desc_node(dev->of_node, index);
+	if (!np)
+		return NULL;
+
+	list_for_each_entry(opp_table, &opp_tables, node) {
+		if (opp_table->np == np) {
+			/*
+			 * Multiple devices can point to the same OPP table and
+			 * so will have same node-pointer, np.
+			 *
+			 * But the OPPs will be considered as shared only if the
+			 * OPP table contains a "opp-shared" property.
+			 */
+			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
+				_get_opp_table_kref(opp_table);
+				managed_table = opp_table;
+			}
+
+			break;
+		}
+	}
+
+	of_node_put(np);
+
+	return managed_table;
+}
+
+/* The caller must call dev_pm_opp_put() after the OPP is used */
+static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
+					  struct device_node *opp_np)
+{
+	struct dev_pm_opp *opp;
+
+	mutex_lock(&opp_table->lock);
+
+	list_for_each_entry(opp, &opp_table->opp_list, node) {
+		if (opp->np == opp_np) {
+			dev_pm_opp_get(opp);
+			mutex_unlock(&opp_table->lock);
+			return opp;
+		}
+	}
+
+	mutex_unlock(&opp_table->lock);
+
+	return NULL;
+}
+
+static struct device_node *of_parse_required_opp(struct device_node *np,
+						 int index)
+{
+	return of_parse_phandle(np, "required-opps", index);
+}
+
+/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
+static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
+{
+	struct opp_table *opp_table;
+	struct device_node *opp_table_np;
+
+	opp_table_np = of_get_parent(opp_np);
+	if (!opp_table_np)
+		goto err;
+
+	/* It is safe to put the node now as all we need now is its address */
+	of_node_put(opp_table_np);
+
+	mutex_lock(&opp_table_lock);
+	list_for_each_entry(opp_table, &opp_tables, node) {
+		if (opp_table_np == opp_table->np) {
+			_get_opp_table_kref(opp_table);
+			mutex_unlock(&opp_table_lock);
+			return opp_table;
+		}
+	}
+	mutex_unlock(&opp_table_lock);
+
+err:
+	return ERR_PTR(-ENODEV);
+}
+
+/* Free resources previously acquired by _opp_table_alloc_required_tables() */
+static void _opp_table_free_required_tables(struct opp_table *opp_table)
+{
+	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
+	int i;
+
+	if (!required_opp_tables)
+		return;
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		if (IS_ERR_OR_NULL(required_opp_tables[i]))
+			continue;
+
+		dev_pm_opp_put_opp_table(required_opp_tables[i]);
+	}
+
+	kfree(required_opp_tables);
+
+	opp_table->required_opp_count = 0;
+	opp_table->required_opp_tables = NULL;
+	list_del(&opp_table->lazy);
+}
+
+/*
+ * Populate all devices and opp tables which are part of "required-opps" list.
+ * Checking only the first OPP node should be enough.
+ */
+static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
+					     struct device *dev,
+					     struct device_node *opp_np)
+{
+	struct opp_table **required_opp_tables;
+	struct device_node *required_np, *np;
+	bool lazy = false;
+	int count, i;
+
+	/* Traversing the first OPP node is all we need */
+	np = of_get_next_available_child(opp_np, NULL);
+	if (!np) {
+		dev_warn(dev, "Empty OPP table\n");
+
+		return;
+	}
+
+	count = of_count_phandle_with_args(np, "required-opps", NULL);
+	if (count <= 0)
+		goto put_np;
+
+	required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
+				      GFP_KERNEL);
+	if (!required_opp_tables)
+		goto put_np;
+
+	opp_table->required_opp_tables = required_opp_tables;
+	opp_table->required_opp_count = count;
+
+	for (i = 0; i < count; i++) {
+		required_np = of_parse_required_opp(np, i);
+		if (!required_np)
+			goto free_required_tables;
+
+		required_opp_tables[i] = _find_table_of_opp_np(required_np);
+		of_node_put(required_np);
+
+		if (IS_ERR(required_opp_tables[i]))
+			lazy = true;
+	}
+
+	/* Let's do the linking later on */
+	if (lazy)
+		list_add(&opp_table->lazy, &lazy_opp_tables);
+
+	goto put_np;
+
+free_required_tables:
+	_opp_table_free_required_tables(opp_table);
+put_np:
+	of_node_put(np);
+}
+
+void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
+			int index)
+{
+	struct device_node *np, *opp_np;
+	u32 val;
+
+	/*
+	 * Only required for backward compatibility with v1 bindings, but isn't
+	 * harmful for other cases. And so we do it unconditionally.
+	 */
+	np = of_node_get(dev->of_node);
+	if (!np)
+		return;
+
+	if (!of_property_read_u32(np, "clock-latency", &val))
+		opp_table->clock_latency_ns_max = val;
+	of_property_read_u32(np, "voltage-tolerance",
+			     &opp_table->voltage_tolerance_v1);
+
+	if (of_find_property(np, "#power-domain-cells", NULL))
+		opp_table->is_genpd = true;
+
+	/* Get OPP table node */
+	opp_np = _opp_of_get_opp_desc_node(np, index);
+	of_node_put(np);
+
+	if (!opp_np)
+		return;
+
+	if (of_property_read_bool(opp_np, "opp-shared"))
+		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
+	else
+		opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
+
+	opp_table->np = opp_np;
+
+	_opp_table_alloc_required_tables(opp_table, dev, opp_np);
+}
+
+void _of_clear_opp_table(struct opp_table *opp_table)
+{
+	_opp_table_free_required_tables(opp_table);
+	of_node_put(opp_table->np);
+}
+
+/*
+ * Release all resources previously acquired with a call to
+ * _of_opp_alloc_required_opps().
+ */
+static void _of_opp_free_required_opps(struct opp_table *opp_table,
+				       struct dev_pm_opp *opp)
+{
+	struct dev_pm_opp **required_opps = opp->required_opps;
+	int i;
+
+	if (!required_opps)
+		return;
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		if (!required_opps[i])
+			continue;
+
+		/* Put the reference back */
+		dev_pm_opp_put(required_opps[i]);
+	}
+
+	opp->required_opps = NULL;
+	kfree(required_opps);
+}
+
+void _of_clear_opp(struct opp_table *opp_table, struct dev_pm_opp *opp)
+{
+	_of_opp_free_required_opps(opp_table, opp);
+	of_node_put(opp->np);
+}
+
+/* Populate all required OPPs which are part of "required-opps" list */
+static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
+				       struct dev_pm_opp *opp)
+{
+	struct dev_pm_opp **required_opps;
+	struct opp_table *required_table;
+	struct device_node *np;
+	int i, ret, count = opp_table->required_opp_count;
+
+	if (!count)
+		return 0;
+
+	required_opps = kcalloc(count, sizeof(*required_opps), GFP_KERNEL);
+	if (!required_opps)
+		return -ENOMEM;
+
+	opp->required_opps = required_opps;
+
+	for (i = 0; i < count; i++) {
+		required_table = opp_table->required_opp_tables[i];
+
+		/* Required table not added yet, we will link later */
+		if (IS_ERR_OR_NULL(required_table))
+			continue;
+
+		np = of_parse_required_opp(opp->np, i);
+		if (unlikely(!np)) {
+			ret = -ENODEV;
+			goto free_required_opps;
+		}
+
+		required_opps[i] = _find_opp_of_np(required_table, np);
+		of_node_put(np);
+
+		if (!required_opps[i]) {
+			pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
+			       __func__, opp->np, i);
+			ret = -ENODEV;
+			goto free_required_opps;
+		}
+	}
+
+	return 0;
+
+free_required_opps:
+	_of_opp_free_required_opps(opp_table, opp);
+
+	return ret;
+}
+
+/* Link required OPPs for an individual OPP */
+static int lazy_link_required_opps(struct opp_table *opp_table,
+				   struct opp_table *new_table, int index)
+{
+	struct device_node *required_np;
+	struct dev_pm_opp *opp;
+
+	list_for_each_entry(opp, &opp_table->opp_list, node) {
+		required_np = of_parse_required_opp(opp->np, index);
+		if (unlikely(!required_np))
+			return -ENODEV;
+
+		opp->required_opps[index] = _find_opp_of_np(new_table, required_np);
+		of_node_put(required_np);
+
+		if (!opp->required_opps[index]) {
+			pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
+			       __func__, opp->np, index);
+			return -ENODEV;
+		}
+	}
+
+	return 0;
+}
+
+/* Link required OPPs for all OPPs of the newly added OPP table */
+static void lazy_link_required_opp_table(struct opp_table *new_table)
+{
+	struct opp_table *opp_table, *temp, **required_opp_tables;
+	struct device_node *required_np, *opp_np, *required_table_np;
+	struct dev_pm_opp *opp;
+	int i, ret;
+
+	mutex_lock(&opp_table_lock);
+
+	list_for_each_entry_safe(opp_table, temp, &lazy_opp_tables, lazy) {
+		bool lazy = false;
+
+		/* opp_np can't be invalid here */
+		opp_np = of_get_next_available_child(opp_table->np, NULL);
+
+		for (i = 0; i < opp_table->required_opp_count; i++) {
+			required_opp_tables = opp_table->required_opp_tables;
+
+			/* Required opp-table is already parsed */
+			if (!IS_ERR(required_opp_tables[i]))
+				continue;
+
+			/* required_np can't be invalid here */
+			required_np = of_parse_required_opp(opp_np, i);
+			required_table_np = of_get_parent(required_np);
+
+			of_node_put(required_table_np);
+			of_node_put(required_np);
+
+			/*
+			 * Newly added table isn't the required opp-table for
+			 * opp_table.
+			 */
+			if (required_table_np != new_table->np) {
+				lazy = true;
+				continue;
+			}
+
+			required_opp_tables[i] = new_table;
+			_get_opp_table_kref(new_table);
+
+			/* Link OPPs now */
+			ret = lazy_link_required_opps(opp_table, new_table, i);
+			if (ret) {
+				/* The OPPs will be marked unusable */
+				lazy = false;
+				break;
+			}
+		}
+
+		of_node_put(opp_np);
+
+		/* All required opp-tables found, remove from lazy list */
+		if (!lazy) {
+			list_del_init(&opp_table->lazy);
+
+			list_for_each_entry(opp, &opp_table->opp_list, node)
+				_required_opps_available(opp, opp_table->required_opp_count);
+		}
+	}
+
+	mutex_unlock(&opp_table_lock);
+}
+
+static int _bandwidth_supported(struct device *dev, struct opp_table *opp_table)
+{
+	struct device_node *np, *opp_np;
+	struct property *prop;
+
+	if (!opp_table) {
+		np = of_node_get(dev->of_node);
+		if (!np)
+			return -ENODEV;
+
+		opp_np = _opp_of_get_opp_desc_node(np, 0);
+		of_node_put(np);
+	} else {
+		opp_np = of_node_get(opp_table->np);
+	}
+
+	/* Lets not fail in case we are parsing opp-v1 bindings */
+	if (!opp_np)
+		return 0;
+
+	/* Checking only first OPP is sufficient */
+	np = of_get_next_available_child(opp_np, NULL);
+	of_node_put(opp_np);
+	if (!np) {
+		dev_err(dev, "OPP table empty\n");
+		return -EINVAL;
+	}
+
+	prop = of_find_property(np, "opp-peak-kBps", NULL);
+	of_node_put(np);
+
+	if (!prop || !prop->length)
+		return 0;
+
+	return 1;
+}
+
+int dev_pm_opp_of_find_icc_paths(struct device *dev,
+				 struct opp_table *opp_table)
+{
+	struct device_node *np;
+	int ret, i, count, num_paths;
+	struct icc_path **paths;
+
+	ret = _bandwidth_supported(dev, opp_table);
+	if (ret == -EINVAL)
+		return 0; /* Empty OPP table is a valid corner-case, let's not fail */
+	else if (ret <= 0)
+		return ret;
+
+	ret = 0;
+
+	np = of_node_get(dev->of_node);
+	if (!np)
+		return 0;
+
+	count = of_count_phandle_with_args(np, "interconnects",
+					   "#interconnect-cells");
+	of_node_put(np);
+	if (count < 0)
+		return 0;
+
+	/* two phandles when #interconnect-cells = <1> */
+	if (count % 2) {
+		dev_err(dev, "%s: Invalid interconnects values\n", __func__);
+		return -EINVAL;
+	}
+
+	num_paths = count / 2;
+	paths = kcalloc(num_paths, sizeof(*paths), GFP_KERNEL);
+	if (!paths)
+		return -ENOMEM;
+
+	for (i = 0; i < num_paths; i++) {
+		paths[i] = of_icc_get_by_index(dev, i);
+		if (IS_ERR(paths[i])) {
+			ret = PTR_ERR(paths[i]);
+			if (ret != -EPROBE_DEFER) {
+				dev_err(dev, "%s: Unable to get path%d: %d\n",
+					__func__, i, ret);
+			}
+			goto err;
+		}
+	}
+
+	if (opp_table) {
+		opp_table->paths = paths;
+		opp_table->path_count = num_paths;
+		return 0;
+	}
+
+err:
+	while (i--)
+		icc_put(paths[i]);
+
+	kfree(paths);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_find_icc_paths);
+
+static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
+			      struct device_node *np)
+{
+	unsigned int levels = opp_table->supported_hw_count;
+	int count, versions, ret, i, j;
+	u32 val;
+
+	if (!opp_table->supported_hw) {
+		/*
+		 * In the case that no supported_hw has been set by the
+		 * platform but there is an opp-supported-hw value set for
+		 * an OPP then the OPP should not be enabled as there is
+		 * no way to see if the hardware supports it.
+		 */
+		if (of_find_property(np, "opp-supported-hw", NULL))
+			return false;
+		else
+			return true;
+	}
+
+	count = of_property_count_u32_elems(np, "opp-supported-hw");
+	if (count <= 0 || count % levels) {
+		dev_err(dev, "%s: Invalid opp-supported-hw property (%d)\n",
+			__func__, count);
+		return false;
+	}
+
+	versions = count / levels;
+
+	/* All levels in at least one of the versions should match */
+	for (i = 0; i < versions; i++) {
+		bool supported = true;
+
+		for (j = 0; j < levels; j++) {
+			ret = of_property_read_u32_index(np, "opp-supported-hw",
+							 i * levels + j, &val);
+			if (ret) {
+				dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
+					 __func__, i * levels + j, ret);
+				return false;
+			}
+
+			/* Check if the level is supported */
+			if (!(val & opp_table->supported_hw[j])) {
+				supported = false;
+				break;
+			}
+		}
+
+		if (supported)
+			return true;
+	}
+
+	return false;
+}
+
+static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
+			      struct opp_table *opp_table)
+{
+	u32 *microvolt, *microamp = NULL, *microwatt = NULL;
+	int supplies = opp_table->regulator_count;
+	int vcount, icount, pcount, ret, i, j;
+	struct property *prop = NULL;
+	char name[NAME_MAX];
+
+	/* Search for "opp-microvolt-<name>" */
+	if (opp_table->prop_name) {
+		snprintf(name, sizeof(name), "opp-microvolt-%s",
+			 opp_table->prop_name);
+		prop = of_find_property(opp->np, name, NULL);
+	}
+
+	if (!prop) {
+		/* Search for "opp-microvolt" */
+		sprintf(name, "opp-microvolt");
+		prop = of_find_property(opp->np, name, NULL);
+
+		/* Missing property isn't a problem, but an invalid entry is */
+		if (!prop) {
+			if (unlikely(supplies == -1)) {
+				/* Initialize regulator_count */
+				opp_table->regulator_count = 0;
+				return 0;
+			}
+
+			if (!supplies)
+				return 0;
+
+			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
+				__func__);
+			return -EINVAL;
+		}
+	}
+
+	if (unlikely(supplies == -1)) {
+		/* Initialize regulator_count */
+		supplies = opp_table->regulator_count = 1;
+	} else if (unlikely(!supplies)) {
+		dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
+		return -EINVAL;
+	}
+
+	vcount = of_property_count_u32_elems(opp->np, name);
+	if (vcount < 0) {
+		dev_err(dev, "%s: Invalid %s property (%d)\n",
+			__func__, name, vcount);
+		return vcount;
+	}
+
+	/* There can be one or three elements per supply */
+	if (vcount != supplies && vcount != supplies * 3) {
+		dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
+			__func__, name, vcount, supplies);
+		return -EINVAL;
+	}
+
+	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
+	if (!microvolt)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
+	if (ret) {
+		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
+		ret = -EINVAL;
+		goto free_microvolt;
+	}
+
+	/* Search for "opp-microamp-<name>" */
+	prop = NULL;
+	if (opp_table->prop_name) {
+		snprintf(name, sizeof(name), "opp-microamp-%s",
+			 opp_table->prop_name);
+		prop = of_find_property(opp->np, name, NULL);
+	}
+
+	if (!prop) {
+		/* Search for "opp-microamp" */
+		sprintf(name, "opp-microamp");
+		prop = of_find_property(opp->np, name, NULL);
+	}
+
+	if (prop) {
+		icount = of_property_count_u32_elems(opp->np, name);
+		if (icount < 0) {
+			dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
+				name, icount);
+			ret = icount;
+			goto free_microvolt;
+		}
+
+		if (icount != supplies) {
+			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
+				__func__, name, icount, supplies);
+			ret = -EINVAL;
+			goto free_microvolt;
+		}
+
+		microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
+		if (!microamp) {
+			ret = -EINVAL;
+			goto free_microvolt;
+		}
+
+		ret = of_property_read_u32_array(opp->np, name, microamp,
+						 icount);
+		if (ret) {
+			dev_err(dev, "%s: error parsing %s: %d\n", __func__,
+				name, ret);
+			ret = -EINVAL;
+			goto free_microamp;
+		}
+	}
+
+	/* Search for "opp-microwatt" */
+	sprintf(name, "opp-microwatt");
+	prop = of_find_property(opp->np, name, NULL);
+
+	if (prop) {
+		pcount = of_property_count_u32_elems(opp->np, name);
+		if (pcount < 0) {
+			dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
+				name, pcount);
+			ret = pcount;
+			goto free_microamp;
+		}
+
+		if (pcount != supplies) {
+			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
+				__func__, name, pcount, supplies);
+			ret = -EINVAL;
+			goto free_microamp;
+		}
+
+		microwatt = kmalloc_array(pcount, sizeof(*microwatt),
+					  GFP_KERNEL);
+		if (!microwatt) {
+			ret = -EINVAL;
+			goto free_microamp;
+		}
+
+		ret = of_property_read_u32_array(opp->np, name, microwatt,
+						 pcount);
+		if (ret) {
+			dev_err(dev, "%s: error parsing %s: %d\n", __func__,
+				name, ret);
+			ret = -EINVAL;
+			goto free_microwatt;
+		}
+	}
+
+	for (i = 0, j = 0; i < supplies; i++) {
+		opp->supplies[i].u_volt = microvolt[j++];
+
+		if (vcount == supplies) {
+			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
+			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
+		} else {
+			opp->supplies[i].u_volt_min = microvolt[j++];
+			opp->supplies[i].u_volt_max = microvolt[j++];
+		}
+
+		if (microamp)
+			opp->supplies[i].u_amp = microamp[i];
+
+		if (microwatt)
+			opp->supplies[i].u_watt = microwatt[i];
+	}
+
+free_microwatt:
+	kfree(microwatt);
+free_microamp:
+	kfree(microamp);
+free_microvolt:
+	kfree(microvolt);
+
+	return ret;
+}
+
+/**
+ * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
+ *				  entries
+ * @dev:	device pointer used to lookup OPP table.
+ *
+ * Free OPPs created using static entries present in DT.
+ */
+void dev_pm_opp_of_remove_table(struct device *dev)
+{
+	dev_pm_opp_remove_table(dev);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
+
+static int _read_rate(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
+		      struct device_node *np)
+{
+	struct property *prop;
+	int i, count, ret;
+	u64 *rates;
+
+	prop = of_find_property(np, "opp-hz", NULL);
+	if (!prop)
+		return -ENODEV;
+
+	count = prop->length / sizeof(u64);
+	if (opp_table->clk_count != count) {
+		pr_err("%s: Count mismatch between opp-hz and clk_count (%d %d)\n",
+		       __func__, count, opp_table->clk_count);
+		return -EINVAL;
+	}
+
+	rates = kmalloc_array(count, sizeof(*rates), GFP_KERNEL);
+	if (!rates)
+		return -ENOMEM;
+
+	ret = of_property_read_u64_array(np, "opp-hz", rates, count);
+	if (ret) {
+		pr_err("%s: Error parsing opp-hz: %d\n", __func__, ret);
+	} else {
+		/*
+		 * Rate is defined as an unsigned long in clk API, and so
+		 * casting explicitly to its type. Must be fixed once rate is 64
+		 * bit guaranteed in clk API.
+		 */
+		for (i = 0; i < count; i++) {
+			new_opp->rates[i] = (unsigned long)rates[i];
+
+			/* This will happen for frequencies > 4.29 GHz */
+			WARN_ON(new_opp->rates[i] != rates[i]);
+		}
+	}
+
+	kfree(rates);
+
+	return ret;
+}
+
+static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
+		    struct device_node *np, bool peak)
+{
+	const char *name = peak ? "opp-peak-kBps" : "opp-avg-kBps";
+	struct property *prop;
+	int i, count, ret;
+	u32 *bw;
+
+	prop = of_find_property(np, name, NULL);
+	if (!prop)
+		return -ENODEV;
+
+	count = prop->length / sizeof(u32);
+	if (opp_table->path_count != count) {
+		pr_err("%s: Mismatch between %s and paths (%d %d)\n",
+				__func__, name, count, opp_table->path_count);
+		return -EINVAL;
+	}
+
+	bw = kmalloc_array(count, sizeof(*bw), GFP_KERNEL);
+	if (!bw)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(np, name, bw, count);
+	if (ret) {
+		pr_err("%s: Error parsing %s: %d\n", __func__, name, ret);
+		goto out;
+	}
+
+	for (i = 0; i < count; i++) {
+		if (peak)
+			new_opp->bandwidth[i].peak = kBps_to_icc(bw[i]);
+		else
+			new_opp->bandwidth[i].avg = kBps_to_icc(bw[i]);
+	}
+
+out:
+	kfree(bw);
+	return ret;
+}
+
+static int _read_opp_key(struct dev_pm_opp *new_opp,
+			 struct opp_table *opp_table, struct device_node *np)
+{
+	bool found = false;
+	int ret;
+
+	ret = _read_rate(new_opp, opp_table, np);
+	if (!ret)
+		found = true;
+	else if (ret != -ENODEV)
+		return ret;
+
+	/*
+	 * Bandwidth consists of peak and average (optional) values:
+	 * opp-peak-kBps = <path1_value path2_value>;
+	 * opp-avg-kBps = <path1_value path2_value>;
+	 */
+	ret = _read_bw(new_opp, opp_table, np, true);
+	if (!ret) {
+		found = true;
+		ret = _read_bw(new_opp, opp_table, np, false);
+	}
+
+	/* The properties were found but we failed to parse them */
+	if (ret && ret != -ENODEV)
+		return ret;
+
+	if (!of_property_read_u32(np, "opp-level", &new_opp->level))
+		found = true;
+
+	if (found)
+		return 0;
+
+	return ret;
+}
+
+/**
+ * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
+ * @opp_table:	OPP table
+ * @dev:	device for which we do this operation
+ * @np:		device node
+ *
+ * This function adds an opp definition to the opp table and returns status. The
+ * opp can be controlled using dev_pm_opp_enable/disable functions and may be
+ * removed by dev_pm_opp_remove.
+ *
+ * Return:
+ * Valid OPP pointer:
+ *		On success
+ * NULL:
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ *		OR if the OPP is not supported by hardware.
+ * ERR_PTR(-EEXIST):
+ *		Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * ERR_PTR(-ENOMEM):
+ *		Memory allocation failure
+ * ERR_PTR(-EINVAL):
+ *		Failed parsing the OPP node
+ */
+static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
+		struct device *dev, struct device_node *np)
+{
+	struct dev_pm_opp *new_opp;
+	u32 val;
+	int ret;
+
+	new_opp = _opp_allocate(opp_table);
+	if (!new_opp)
+		return ERR_PTR(-ENOMEM);
+
+	ret = _read_opp_key(new_opp, opp_table, np);
+	if (ret < 0) {
+		dev_err(dev, "%s: opp key field not found\n", __func__);
+		goto free_opp;
+	}
+
+	/* Check if the OPP supports hardware's hierarchy of versions or not */
+	if (!_opp_is_supported(dev, opp_table, np)) {
+		dev_dbg(dev, "OPP not supported by hardware: %s\n",
+			of_node_full_name(np));
+		goto free_opp;
+	}
+
+	new_opp->turbo = of_property_read_bool(np, "turbo-mode");
+
+	new_opp->np = of_node_get(np);
+	new_opp->dynamic = false;
+	new_opp->available = true;
+
+	ret = _of_opp_alloc_required_opps(opp_table, new_opp);
+	if (ret)
+		goto free_opp;
+
+	if (!of_property_read_u32(np, "clock-latency-ns", &val))
+		new_opp->clock_latency_ns = val;
+
+	ret = opp_parse_supplies(new_opp, dev, opp_table);
+	if (ret)
+		goto free_required_opps;
+
+	if (opp_table->is_genpd)
+		new_opp->pstate = pm_genpd_opp_to_performance_state(dev, new_opp);
+
+	ret = _opp_add(dev, new_opp, opp_table);
+	if (ret) {
+		/* Don't return error for duplicate OPPs */
+		if (ret == -EBUSY)
+			ret = 0;
+		goto free_required_opps;
+	}
+
+	/* OPP to select on device suspend */
+	if (of_property_read_bool(np, "opp-suspend")) {
+		if (opp_table->suspend_opp) {
+			/* Pick the OPP with higher rate/bw/level as suspend OPP */
+			if (_opp_compare_key(opp_table, new_opp, opp_table->suspend_opp) == 1) {
+				opp_table->suspend_opp->suspend = false;
+				new_opp->suspend = true;
+				opp_table->suspend_opp = new_opp;
+			}
+		} else {
+			new_opp->suspend = true;
+			opp_table->suspend_opp = new_opp;
+		}
+	}
+
+	if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
+		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
+
+	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu level:%u\n",
+		 __func__, new_opp->turbo, new_opp->rates[0],
+		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
+		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns,
+		 new_opp->level);
+
+	/*
+	 * Notify the changes in the availability of the operable
+	 * frequency/voltage list.
+	 */
+	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
+	return new_opp;
+
+free_required_opps:
+	_of_opp_free_required_opps(opp_table, new_opp);
+free_opp:
+	_opp_free(new_opp);
+
+	return ret ? ERR_PTR(ret) : NULL;
+}
+
+/* Initializes OPP tables based on new bindings */
+static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
+{
+	struct device_node *np;
+	int ret, count = 0;
+	struct dev_pm_opp *opp;
+
+	/* OPP table is already initialized for the device */
+	mutex_lock(&opp_table->lock);
+	if (opp_table->parsed_static_opps) {
+		opp_table->parsed_static_opps++;
+		mutex_unlock(&opp_table->lock);
+		return 0;
+	}
+
+	opp_table->parsed_static_opps = 1;
+	mutex_unlock(&opp_table->lock);
+
+	/* We have opp-table node now, iterate over it and add OPPs */
+	for_each_available_child_of_node(opp_table->np, np) {
+		opp = _opp_add_static_v2(opp_table, dev, np);
+		if (IS_ERR(opp)) {
+			ret = PTR_ERR(opp);
+			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
+				ret);
+			of_node_put(np);
+			goto remove_static_opp;
+		} else if (opp) {
+			count++;
+		}
+	}
+
+	/* There should be one or more OPPs defined */
+	if (!count) {
+		dev_err(dev, "%s: no supported OPPs", __func__);
+		ret = -ENOENT;
+		goto remove_static_opp;
+	}
+
+	list_for_each_entry(opp, &opp_table->opp_list, node) {
+		/* Any non-zero performance state would enable the feature */
+		if (opp->pstate) {
+			opp_table->genpd_performance_state = true;
+			break;
+		}
+	}
+
+	lazy_link_required_opp_table(opp_table);
+
+	return 0;
+
+remove_static_opp:
+	_opp_remove_all_static(opp_table);
+
+	return ret;
+}
+
+/* Initializes OPP tables based on old-deprecated bindings */
+static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
+{
+	const struct property *prop;
+	const __be32 *val;
+	int nr, ret = 0;
+
+	mutex_lock(&opp_table->lock);
+	if (opp_table->parsed_static_opps) {
+		opp_table->parsed_static_opps++;
+		mutex_unlock(&opp_table->lock);
+		return 0;
+	}
+
+	opp_table->parsed_static_opps = 1;
+	mutex_unlock(&opp_table->lock);
+
+	prop = of_find_property(dev->of_node, "operating-points", NULL);
+	if (!prop) {
+		ret = -ENODEV;
+		goto remove_static_opp;
+	}
+	if (!prop->value) {
+		ret = -ENODATA;
+		goto remove_static_opp;
+	}
+
+	/*
+	 * Each OPP is a set of tuples consisting of frequency and
+	 * voltage like <freq-kHz vol-uV>.
+	 */
+	nr = prop->length / sizeof(u32);
+	if (nr % 2) {
+		dev_err(dev, "%s: Invalid OPP table\n", __func__);
+		ret = -EINVAL;
+		goto remove_static_opp;
+	}
+
+	val = prop->value;
+	while (nr) {
+		unsigned long freq = be32_to_cpup(val++) * 1000;
+		unsigned long volt = be32_to_cpup(val++);
+
+		ret = _opp_add_v1(opp_table, dev, freq, volt, false);
+		if (ret) {
+			dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
+				__func__, freq, ret);
+			goto remove_static_opp;
+		}
+		nr -= 2;
+	}
+
+	return 0;
+
+remove_static_opp:
+	_opp_remove_all_static(opp_table);
+
+	return ret;
+}
+
+static int _of_add_table_indexed(struct device *dev, int index)
+{
+	struct opp_table *opp_table;
+	int ret, count;
+
+	if (index) {
+		/*
+		 * If only one phandle is present, then the same OPP table
+		 * applies for all index requests.
+		 */
+		count = of_count_phandle_with_args(dev->of_node,
+						   "operating-points-v2", NULL);
+		if (count == 1)
+			index = 0;
+	}
+
+	opp_table = _add_opp_table_indexed(dev, index, true);
+	if (IS_ERR(opp_table))
+		return PTR_ERR(opp_table);
+
+	/*
+	 * OPPs have two version of bindings now. Also try the old (v1)
+	 * bindings for backward compatibility with older dtbs.
+	 */
+	if (opp_table->np)
+		ret = _of_add_opp_table_v2(dev, opp_table);
+	else
+		ret = _of_add_opp_table_v1(dev, opp_table);
+
+	if (ret)
+		dev_pm_opp_put_opp_table(opp_table);
+
+	return ret;
+}
+
+static void devm_pm_opp_of_table_release(void *data)
+{
+	dev_pm_opp_of_remove_table(data);
+}
+
+static int _devm_of_add_table_indexed(struct device *dev, int index)
+{
+	int ret;
+
+	ret = _of_add_table_indexed(dev, index);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_pm_opp_of_table_release, dev);
+}
+
+/**
+ * devm_pm_opp_of_add_table() - Initialize opp table from device tree
+ * @dev:	device pointer used to lookup OPP table.
+ *
+ * Register the initial OPP table with the OPP library for given device.
+ *
+ * The opp_table structure will be freed after the device is destroyed.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -ENODEV	when 'operating-points' property is not found or is invalid data
+ *		in device node.
+ * -ENODATA	when empty 'operating-points' property is found
+ * -EINVAL	when invalid entries are found in opp-v2 table
+ */
+int devm_pm_opp_of_add_table(struct device *dev)
+{
+	return _devm_of_add_table_indexed(dev, 0);
+}
+EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table);
+
+/**
+ * dev_pm_opp_of_add_table() - Initialize opp table from device tree
+ * @dev:	device pointer used to lookup OPP table.
+ *
+ * Register the initial OPP table with the OPP library for given device.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -ENODEV	when 'operating-points' property is not found or is invalid data
+ *		in device node.
+ * -ENODATA	when empty 'operating-points' property is found
+ * -EINVAL	when invalid entries are found in opp-v2 table
+ */
+int dev_pm_opp_of_add_table(struct device *dev)
+{
+	return _of_add_table_indexed(dev, 0);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
+
+/**
+ * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
+ * @dev:	device pointer used to lookup OPP table.
+ * @index:	Index number.
+ *
+ * Register the initial OPP table with the OPP library for given device only
+ * using the "operating-points-v2" property.
+ *
+ * Return: Refer to dev_pm_opp_of_add_table() for return values.
+ */
+int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
+{
+	return _of_add_table_indexed(dev, index);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);
+
+/**
+ * devm_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
+ * @dev:	device pointer used to lookup OPP table.
+ * @index:	Index number.
+ *
+ * This is a resource-managed variant of dev_pm_opp_of_add_table_indexed().
+ */
+int devm_pm_opp_of_add_table_indexed(struct device *dev, int index)
+{
+	return _devm_of_add_table_indexed(dev, index);
+}
+EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table_indexed);
+
+/* CPU device specific helpers */
+
+/**
+ * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
+ * @cpumask:	cpumask for which OPP table needs to be removed
+ *
+ * This removes the OPP tables for CPUs present in the @cpumask.
+ * This should be used only to remove static entries created from DT.
+ */
+void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
+{
+	_dev_pm_opp_cpumask_remove_table(cpumask, -1);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
+
+/**
+ * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
+ * @cpumask:	cpumask for which OPP table needs to be added.
+ *
+ * This adds the OPP tables for CPUs present in the @cpumask.
+ */
+int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
+{
+	struct device *cpu_dev;
+	int cpu, ret;
+
+	if (WARN_ON(cpumask_empty(cpumask)))
+		return -ENODEV;
+
+	for_each_cpu(cpu, cpumask) {
+		cpu_dev = get_cpu_device(cpu);
+		if (!cpu_dev) {
+			pr_err("%s: failed to get cpu%d device\n", __func__,
+			       cpu);
+			ret = -ENODEV;
+			goto remove_table;
+		}
+
+		ret = dev_pm_opp_of_add_table(cpu_dev);
+		if (ret) {
+			/*
+			 * OPP may get registered dynamically, don't print error
+			 * message here.
+			 */
+			pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
+				 __func__, cpu, ret);
+
+			goto remove_table;
+		}
+	}
+
+	return 0;
+
+remove_table:
+	/* Free all other OPPs */
+	_dev_pm_opp_cpumask_remove_table(cpumask, cpu);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
+
+/*
+ * Works only for OPP v2 bindings.
+ *
+ * Returns -ENOENT if operating-points-v2 bindings aren't supported.
+ */
+/**
+ * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
+ *				      @cpu_dev using operating-points-v2
+ *				      bindings.
+ *
+ * @cpu_dev:	CPU device for which we do this operation
+ * @cpumask:	cpumask to update with information of sharing CPUs
+ *
+ * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
+ *
+ * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
+ */
+int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
+				   struct cpumask *cpumask)
+{
+	struct device_node *np, *tmp_np, *cpu_np;
+	int cpu, ret = 0;
+
+	/* Get OPP descriptor node */
+	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+	if (!np) {
+		dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
+		return -ENOENT;
+	}
+
+	cpumask_set_cpu(cpu_dev->id, cpumask);
+
+	/* OPPs are shared ? */
+	if (!of_property_read_bool(np, "opp-shared"))
+		goto put_cpu_node;
+
+	for_each_possible_cpu(cpu) {
+		if (cpu == cpu_dev->id)
+			continue;
+
+		cpu_np = of_cpu_device_node_get(cpu);
+		if (!cpu_np) {
+			dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
+				__func__, cpu);
+			ret = -ENOENT;
+			goto put_cpu_node;
+		}
+
+		/* Get OPP descriptor node */
+		tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
+		of_node_put(cpu_np);
+		if (!tmp_np) {
+			pr_err("%pOF: Couldn't find opp node\n", cpu_np);
+			ret = -ENOENT;
+			goto put_cpu_node;
+		}
+
+		/* CPUs are sharing opp node */
+		if (np == tmp_np)
+			cpumask_set_cpu(cpu, cpumask);
+
+		of_node_put(tmp_np);
+	}
+
+put_cpu_node:
+	of_node_put(np);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
+
+/**
+ * of_get_required_opp_performance_state() - Search for required OPP and return its performance state.
+ * @np: Node that contains the "required-opps" property.
+ * @index: Index of the phandle to parse.
+ *
+ * Returns the performance state of the OPP pointed out by the "required-opps"
+ * property at @index in @np.
+ *
+ * Return: Zero or positive performance state on success, otherwise negative
+ * value on errors.
+ */
+int of_get_required_opp_performance_state(struct device_node *np, int index)
+{
+	struct dev_pm_opp *opp;
+	struct device_node *required_np;
+	struct opp_table *opp_table;
+	int pstate = -EINVAL;
+
+	required_np = of_parse_required_opp(np, index);
+	if (!required_np)
+		return -ENODEV;
+
+	opp_table = _find_table_of_opp_np(required_np);
+	if (IS_ERR(opp_table)) {
+		pr_err("%s: Failed to find required OPP table %pOF: %ld\n",
+		       __func__, np, PTR_ERR(opp_table));
+		goto put_required_np;
+	}
+
+	opp = _find_opp_of_np(opp_table, required_np);
+	if (opp) {
+		pstate = opp->pstate;
+		dev_pm_opp_put(opp);
+	}
+
+	dev_pm_opp_put_opp_table(opp_table);
+
+put_required_np:
+	of_node_put(required_np);
+
+	return pstate;
+}
+EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);
+
+/**
+ * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
+ * @opp:	opp for which DT node has to be returned for
+ *
+ * Return: DT node corresponding to the opp, else 0 on success.
+ *
+ * The caller needs to put the node with of_node_put() after using it.
+ */
+struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
+{
+	if (IS_ERR_OR_NULL(opp)) {
+		pr_err("%s: Invalid parameters\n", __func__);
+		return NULL;
+	}
+
+	return of_node_get(opp->np);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);
+
+/*
+ * Callback function provided to the Energy Model framework upon registration.
+ * It provides the power used by @dev at @kHz if it is the frequency of an
+ * existing OPP, or at the frequency of the first OPP above @kHz otherwise
+ * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
+ * frequency and @uW to the associated power.
+ *
+ * Returns 0 on success or a proper -EINVAL value in case of error.
+ */
+static int __maybe_unused
+_get_dt_power(struct device *dev, unsigned long *uW, unsigned long *kHz)
+{
+	struct dev_pm_opp *opp;
+	unsigned long opp_freq, opp_power;
+
+	/* Find the right frequency and related OPP */
+	opp_freq = *kHz * 1000;
+	opp = dev_pm_opp_find_freq_ceil(dev, &opp_freq);
+	if (IS_ERR(opp))
+		return -EINVAL;
+
+	opp_power = dev_pm_opp_get_power(opp);
+	dev_pm_opp_put(opp);
+	if (!opp_power)
+		return -EINVAL;
+
+	*kHz = opp_freq / 1000;
+	*uW = opp_power;
+
+	return 0;
+}
+
+/*
+ * Callback function provided to the Energy Model framework upon registration.
+ * This computes the power estimated by @dev at @kHz if it is the frequency
+ * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise
+ * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
+ * frequency and @uW to the associated power. The power is estimated as
+ * P = C * V^2 * f with C being the device's capacitance and V and f
+ * respectively the voltage and frequency of the OPP.
+ *
+ * Returns -EINVAL if the power calculation failed because of missing
+ * parameters, 0 otherwise.
+ */
+static int __maybe_unused _get_power(struct device *dev, unsigned long *uW,
+				     unsigned long *kHz)
+{
+	struct dev_pm_opp *opp;
+	struct device_node *np;
+	unsigned long mV, Hz;
+	u32 cap;
+	u64 tmp;
+	int ret;
+
+	np = of_node_get(dev->of_node);
+	if (!np)
+		return -EINVAL;
+
+	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
+	of_node_put(np);
+	if (ret)
+		return -EINVAL;
+
+	Hz = *kHz * 1000;
+	opp = dev_pm_opp_find_freq_ceil(dev, &Hz);
+	if (IS_ERR(opp))
+		return -EINVAL;
+
+	mV = dev_pm_opp_get_voltage(opp) / 1000;
+	dev_pm_opp_put(opp);
+	if (!mV)
+		return -EINVAL;
+
+	tmp = (u64)cap * mV * mV * (Hz / 1000000);
+	/* Provide power in micro-Watts */
+	do_div(tmp, 1000000);
+
+	*uW = (unsigned long)tmp;
+	*kHz = Hz / 1000;
+
+	return 0;
+}
+
+static bool _of_has_opp_microwatt_property(struct device *dev)
+{
+	unsigned long power, freq = 0;
+	struct dev_pm_opp *opp;
+
+	/* Check if at least one OPP has needed property */
+	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+	if (IS_ERR(opp))
+		return false;
+
+	power = dev_pm_opp_get_power(opp);
+	dev_pm_opp_put(opp);
+	if (!power)
+		return false;
+
+	return true;
+}
+
+/**
+ * dev_pm_opp_of_register_em() - Attempt to register an Energy Model
+ * @dev		: Device for which an Energy Model has to be registered
+ * @cpus	: CPUs for which an Energy Model has to be registered. For
+ *		other type of devices it should be set to NULL.
+ *
+ * This checks whether the "dynamic-power-coefficient" devicetree property has
+ * been specified, and tries to register an Energy Model with it if it has.
+ * Having this property means the voltages are known for OPPs and the EM
+ * might be calculated.
+ */
+int dev_pm_opp_of_register_em(struct device *dev, struct cpumask *cpus)
+{
+	struct em_data_callback em_cb;
+	struct device_node *np;
+	int ret, nr_opp;
+	u32 cap;
+
+	if (IS_ERR_OR_NULL(dev)) {
+		ret = -EINVAL;
+		goto failed;
+	}
+
+	nr_opp = dev_pm_opp_get_opp_count(dev);
+	if (nr_opp <= 0) {
+		ret = -EINVAL;
+		goto failed;
+	}
+
+	/* First, try to find more precised Energy Model in DT */
+	if (_of_has_opp_microwatt_property(dev)) {
+		EM_SET_ACTIVE_POWER_CB(em_cb, _get_dt_power);
+		goto register_em;
+	}
+
+	np = of_node_get(dev->of_node);
+	if (!np) {
+		ret = -EINVAL;
+		goto failed;
+	}
+
+	/*
+	 * Register an EM only if the 'dynamic-power-coefficient' property is
+	 * set in devicetree. It is assumed the voltage values are known if that
+	 * property is set since it is useless otherwise. If voltages are not
+	 * known, just let the EM registration fail with an error to alert the
+	 * user about the inconsistent configuration.
+	 */
+	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
+	of_node_put(np);
+	if (ret || !cap) {
+		dev_dbg(dev, "Couldn't find proper 'dynamic-power-coefficient' in DT\n");
+		ret = -EINVAL;
+		goto failed;
+	}
+
+	EM_SET_ACTIVE_POWER_CB(em_cb, _get_power);
+
+register_em:
+	ret = em_dev_register_perf_domain(dev, nr_opp, &em_cb, cpus, true);
+	if (ret)
+		goto failed;
+
+	return 0;
+
+failed:
+	dev_dbg(dev, "Couldn't register Energy Model %d\n", ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em);