Adding upstream version 6.1.76.upstream/6.1.76upstream

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

9 files changed, 1935 insertions, 0 deletions

diff --git a/drivers/gnss/Kconfig b/drivers/gnss/Kconfig
new file mode 100644
index 000000000..d7fe265c2
--- /dev/null
+++ b/drivers/gnss/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# GNSS receiver configuration
+#
+
+menuconfig GNSS
+	tristate "GNSS receiver support"
+	help
+	  Say Y here if you have a GNSS receiver (e.g. a GPS receiver).
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gnss.
+
+if GNSS
+
+config GNSS_SERIAL
+	tristate
+
+config GNSS_MTK_SERIAL
+	tristate "Mediatek GNSS receiver support"
+	depends on SERIAL_DEV_BUS
+	select GNSS_SERIAL
+	help
+	  Say Y here if you have a Mediatek-based GNSS receiver which uses a
+	  serial interface.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gnss-mtk.
+
+	  If unsure, say N.
+
+config GNSS_SIRF_SERIAL
+	tristate "SiRFstar GNSS receiver support"
+	depends on SERIAL_DEV_BUS
+	help
+	  Say Y here if you have a SiRFstar-based GNSS receiver which uses a
+	  serial interface.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gnss-sirf.
+
+	  If unsure, say N.
+
+config GNSS_UBX_SERIAL
+	tristate "u-blox GNSS receiver support"
+	depends on SERIAL_DEV_BUS
+	select GNSS_SERIAL
+	help
+	  Say Y here if you have a u-blox GNSS receiver which uses a serial
+	  interface.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gnss-ubx.
+
+	  If unsure, say N.
+
+config GNSS_USB
+	tristate "USB GNSS receiver support"
+	depends on USB
+	help
+	  Say Y here if you have a GNSS receiver which uses a USB interface.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gnss-usb.
+
+	  If unsure, say N.
+
+endif # GNSS
diff --git a/drivers/gnss/Makefile b/drivers/gnss/Makefile
new file mode 100644
index 000000000..bb2cbada3
--- /dev/null
+++ b/drivers/gnss/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the GNSS subsystem.
+#
+
+obj-$(CONFIG_GNSS)			+= gnss.o
+gnss-y := core.o
+
+obj-$(CONFIG_GNSS_SERIAL)		+= gnss-serial.o
+gnss-serial-y := serial.o
+
+obj-$(CONFIG_GNSS_MTK_SERIAL)		+= gnss-mtk.o
+gnss-mtk-y := mtk.o
+
+obj-$(CONFIG_GNSS_SIRF_SERIAL)		+= gnss-sirf.o
+gnss-sirf-y := sirf.o
+
+obj-$(CONFIG_GNSS_UBX_SERIAL)		+= gnss-ubx.o
+gnss-ubx-y := ubx.o
+
+obj-$(CONFIG_GNSS_USB)			+= gnss-usb.o
+gnss-usb-y := usb.o
diff --git a/drivers/gnss/core.c b/drivers/gnss/core.c
new file mode 100644
index 000000000..1e82b7967
--- /dev/null
+++ b/drivers/gnss/core.c
@@ -0,0 +1,421 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GNSS receiver core
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cdev.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/gnss.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+
+#define GNSS_FLAG_HAS_WRITE_RAW		BIT(0)
+
+#define GNSS_MINORS	16
+
+static DEFINE_IDA(gnss_minors);
+static dev_t gnss_first;
+
+/* FIFO size must be a power of two */
+#define GNSS_READ_FIFO_SIZE	4096
+#define GNSS_WRITE_BUF_SIZE	1024
+
+#define to_gnss_device(d) container_of((d), struct gnss_device, dev)
+
+static int gnss_open(struct inode *inode, struct file *file)
+{
+	struct gnss_device *gdev;
+	int ret = 0;
+
+	gdev = container_of(inode->i_cdev, struct gnss_device, cdev);
+
+	get_device(&gdev->dev);
+
+	stream_open(inode, file);
+	file->private_data = gdev;
+
+	down_write(&gdev->rwsem);
+	if (gdev->disconnected) {
+		ret = -ENODEV;
+		goto unlock;
+	}
+
+	if (gdev->count++ == 0) {
+		ret = gdev->ops->open(gdev);
+		if (ret)
+			gdev->count--;
+	}
+unlock:
+	up_write(&gdev->rwsem);
+
+	if (ret)
+		put_device(&gdev->dev);
+
+	return ret;
+}
+
+static int gnss_release(struct inode *inode, struct file *file)
+{
+	struct gnss_device *gdev = file->private_data;
+
+	down_write(&gdev->rwsem);
+	if (gdev->disconnected)
+		goto unlock;
+
+	if (--gdev->count == 0) {
+		gdev->ops->close(gdev);
+		kfifo_reset(&gdev->read_fifo);
+	}
+unlock:
+	up_write(&gdev->rwsem);
+
+	put_device(&gdev->dev);
+
+	return 0;
+}
+
+static ssize_t gnss_read(struct file *file, char __user *buf,
+				size_t count, loff_t *pos)
+{
+	struct gnss_device *gdev = file->private_data;
+	unsigned int copied;
+	int ret;
+
+	mutex_lock(&gdev->read_mutex);
+	while (kfifo_is_empty(&gdev->read_fifo)) {
+		mutex_unlock(&gdev->read_mutex);
+
+		if (gdev->disconnected)
+			return 0;
+
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		ret = wait_event_interruptible(gdev->read_queue,
+				gdev->disconnected ||
+				!kfifo_is_empty(&gdev->read_fifo));
+		if (ret)
+			return -ERESTARTSYS;
+
+		mutex_lock(&gdev->read_mutex);
+	}
+
+	ret = kfifo_to_user(&gdev->read_fifo, buf, count, &copied);
+	if (ret == 0)
+		ret = copied;
+
+	mutex_unlock(&gdev->read_mutex);
+
+	return ret;
+}
+
+static ssize_t gnss_write(struct file *file, const char __user *buf,
+				size_t count, loff_t *pos)
+{
+	struct gnss_device *gdev = file->private_data;
+	size_t written = 0;
+	int ret;
+
+	if (gdev->disconnected)
+		return -EIO;
+
+	if (!count)
+		return 0;
+
+	if (!(gdev->flags & GNSS_FLAG_HAS_WRITE_RAW))
+		return -EIO;
+
+	/* Ignoring O_NONBLOCK, write_raw() is synchronous. */
+
+	ret = mutex_lock_interruptible(&gdev->write_mutex);
+	if (ret)
+		return -ERESTARTSYS;
+
+	for (;;) {
+		size_t n = count - written;
+
+		if (n > GNSS_WRITE_BUF_SIZE)
+			n = GNSS_WRITE_BUF_SIZE;
+
+		if (copy_from_user(gdev->write_buf, buf, n)) {
+			ret = -EFAULT;
+			goto out_unlock;
+		}
+
+		/*
+		 * Assumes write_raw can always accept GNSS_WRITE_BUF_SIZE
+		 * bytes.
+		 *
+		 * FIXME: revisit
+		 */
+		down_read(&gdev->rwsem);
+		if (!gdev->disconnected)
+			ret = gdev->ops->write_raw(gdev, gdev->write_buf, n);
+		else
+			ret = -EIO;
+		up_read(&gdev->rwsem);
+
+		if (ret < 0)
+			break;
+
+		written += ret;
+		buf += ret;
+
+		if (written == count)
+			break;
+	}
+
+	if (written)
+		ret = written;
+out_unlock:
+	mutex_unlock(&gdev->write_mutex);
+
+	return ret;
+}
+
+static __poll_t gnss_poll(struct file *file, poll_table *wait)
+{
+	struct gnss_device *gdev = file->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &gdev->read_queue, wait);
+
+	if (!kfifo_is_empty(&gdev->read_fifo))
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (gdev->disconnected)
+		mask |= EPOLLHUP;
+
+	return mask;
+}
+
+static const struct file_operations gnss_fops = {
+	.owner		= THIS_MODULE,
+	.open		= gnss_open,
+	.release	= gnss_release,
+	.read		= gnss_read,
+	.write		= gnss_write,
+	.poll		= gnss_poll,
+	.llseek		= no_llseek,
+};
+
+static struct class *gnss_class;
+
+static void gnss_device_release(struct device *dev)
+{
+	struct gnss_device *gdev = to_gnss_device(dev);
+
+	kfree(gdev->write_buf);
+	kfifo_free(&gdev->read_fifo);
+	ida_free(&gnss_minors, gdev->id);
+	kfree(gdev);
+}
+
+struct gnss_device *gnss_allocate_device(struct device *parent)
+{
+	struct gnss_device *gdev;
+	struct device *dev;
+	int id;
+	int ret;
+
+	gdev = kzalloc(sizeof(*gdev), GFP_KERNEL);
+	if (!gdev)
+		return NULL;
+
+	id = ida_alloc_max(&gnss_minors, GNSS_MINORS - 1, GFP_KERNEL);
+	if (id < 0) {
+		kfree(gdev);
+		return NULL;
+	}
+
+	gdev->id = id;
+
+	dev = &gdev->dev;
+	device_initialize(dev);
+	dev->devt = gnss_first + id;
+	dev->class = gnss_class;
+	dev->parent = parent;
+	dev->release = gnss_device_release;
+	dev_set_drvdata(dev, gdev);
+	dev_set_name(dev, "gnss%d", id);
+
+	init_rwsem(&gdev->rwsem);
+	mutex_init(&gdev->read_mutex);
+	mutex_init(&gdev->write_mutex);
+	init_waitqueue_head(&gdev->read_queue);
+
+	ret = kfifo_alloc(&gdev->read_fifo, GNSS_READ_FIFO_SIZE, GFP_KERNEL);
+	if (ret)
+		goto err_put_device;
+
+	gdev->write_buf = kzalloc(GNSS_WRITE_BUF_SIZE, GFP_KERNEL);
+	if (!gdev->write_buf)
+		goto err_put_device;
+
+	cdev_init(&gdev->cdev, &gnss_fops);
+	gdev->cdev.owner = THIS_MODULE;
+
+	return gdev;
+
+err_put_device:
+	put_device(dev);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(gnss_allocate_device);
+
+void gnss_put_device(struct gnss_device *gdev)
+{
+	put_device(&gdev->dev);
+}
+EXPORT_SYMBOL_GPL(gnss_put_device);
+
+int gnss_register_device(struct gnss_device *gdev)
+{
+	int ret;
+
+	/* Set a flag which can be accessed without holding the rwsem. */
+	if (gdev->ops->write_raw != NULL)
+		gdev->flags |= GNSS_FLAG_HAS_WRITE_RAW;
+
+	ret = cdev_device_add(&gdev->cdev, &gdev->dev);
+	if (ret) {
+		dev_err(&gdev->dev, "failed to add device: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gnss_register_device);
+
+void gnss_deregister_device(struct gnss_device *gdev)
+{
+	down_write(&gdev->rwsem);
+	gdev->disconnected = true;
+	if (gdev->count) {
+		wake_up_interruptible(&gdev->read_queue);
+		gdev->ops->close(gdev);
+	}
+	up_write(&gdev->rwsem);
+
+	cdev_device_del(&gdev->cdev, &gdev->dev);
+}
+EXPORT_SYMBOL_GPL(gnss_deregister_device);
+
+/*
+ * Caller guarantees serialisation.
+ *
+ * Must not be called for a closed device.
+ */
+int gnss_insert_raw(struct gnss_device *gdev, const unsigned char *buf,
+				size_t count)
+{
+	int ret;
+
+	ret = kfifo_in(&gdev->read_fifo, buf, count);
+
+	wake_up_interruptible(&gdev->read_queue);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gnss_insert_raw);
+
+static const char * const gnss_type_names[GNSS_TYPE_COUNT] = {
+	[GNSS_TYPE_NMEA]	= "NMEA",
+	[GNSS_TYPE_SIRF]	= "SiRF",
+	[GNSS_TYPE_UBX]		= "UBX",
+	[GNSS_TYPE_MTK]		= "MTK",
+};
+
+static const char *gnss_type_name(struct gnss_device *gdev)
+{
+	const char *name = NULL;
+
+	if (gdev->type < GNSS_TYPE_COUNT)
+		name = gnss_type_names[gdev->type];
+
+	if (!name)
+		dev_WARN(&gdev->dev, "type name not defined\n");
+
+	return name;
+}
+
+static ssize_t type_show(struct device *dev, struct device_attribute *attr,
+				char *buf)
+{
+	struct gnss_device *gdev = to_gnss_device(dev);
+
+	return sprintf(buf, "%s\n", gnss_type_name(gdev));
+}
+static DEVICE_ATTR_RO(type);
+
+static struct attribute *gnss_attrs[] = {
+	&dev_attr_type.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(gnss);
+
+static int gnss_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct gnss_device *gdev = to_gnss_device(dev);
+	int ret;
+
+	ret = add_uevent_var(env, "GNSS_TYPE=%s", gnss_type_name(gdev));
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int __init gnss_module_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&gnss_first, 0, GNSS_MINORS, "gnss");
+	if (ret < 0) {
+		pr_err("failed to allocate device numbers: %d\n", ret);
+		return ret;
+	}
+
+	gnss_class = class_create(THIS_MODULE, "gnss");
+	if (IS_ERR(gnss_class)) {
+		ret = PTR_ERR(gnss_class);
+		pr_err("failed to create class: %d\n", ret);
+		goto err_unregister_chrdev;
+	}
+
+	gnss_class->dev_groups = gnss_groups;
+	gnss_class->dev_uevent = gnss_uevent;
+
+	pr_info("GNSS driver registered with major %d\n", MAJOR(gnss_first));
+
+	return 0;
+
+err_unregister_chrdev:
+	unregister_chrdev_region(gnss_first, GNSS_MINORS);
+
+	return ret;
+}
+module_init(gnss_module_init);
+
+static void __exit gnss_module_exit(void)
+{
+	class_destroy(gnss_class);
+	unregister_chrdev_region(gnss_first, GNSS_MINORS);
+	ida_destroy(&gnss_minors);
+}
+module_exit(gnss_module_exit);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("GNSS receiver core");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gnss/mtk.c b/drivers/gnss/mtk.c
new file mode 100644
index 000000000..c62b1211f
--- /dev/null
+++ b/drivers/gnss/mtk.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mediatek GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+#include <linux/serdev.h>
+
+#include "serial.h"
+
+struct mtk_data {
+	struct regulator *vbackup;
+	struct regulator *vcc;
+};
+
+static int mtk_set_active(struct gnss_serial *gserial)
+{
+	struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+	int ret;
+
+	ret = regulator_enable(data->vcc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mtk_set_standby(struct gnss_serial *gserial)
+{
+	struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+	int ret;
+
+	ret = regulator_disable(data->vcc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mtk_set_power(struct gnss_serial *gserial,
+			 enum gnss_serial_pm_state state)
+{
+	switch (state) {
+	case GNSS_SERIAL_ACTIVE:
+		return mtk_set_active(gserial);
+	case GNSS_SERIAL_OFF:
+	case GNSS_SERIAL_STANDBY:
+		return mtk_set_standby(gserial);
+	}
+
+	return -EINVAL;
+}
+
+static const struct gnss_serial_ops mtk_gserial_ops = {
+	.set_power = mtk_set_power,
+};
+
+static int mtk_probe(struct serdev_device *serdev)
+{
+	struct gnss_serial *gserial;
+	struct mtk_data *data;
+	int ret;
+
+	gserial = gnss_serial_allocate(serdev, sizeof(*data));
+	if (IS_ERR(gserial)) {
+		ret = PTR_ERR(gserial);
+		return ret;
+	}
+
+	gserial->ops = &mtk_gserial_ops;
+
+	gserial->gdev->type = GNSS_TYPE_MTK;
+
+	data = gnss_serial_get_drvdata(gserial);
+
+	data->vcc = devm_regulator_get(&serdev->dev, "vcc");
+	if (IS_ERR(data->vcc)) {
+		ret = PTR_ERR(data->vcc);
+		goto err_free_gserial;
+	}
+
+	data->vbackup = devm_regulator_get_optional(&serdev->dev, "vbackup");
+	if (IS_ERR(data->vbackup)) {
+		ret = PTR_ERR(data->vbackup);
+		if (ret == -ENODEV)
+			data->vbackup = NULL;
+		else
+			goto err_free_gserial;
+	}
+
+	if (data->vbackup) {
+		ret = regulator_enable(data->vbackup);
+		if (ret)
+			goto err_free_gserial;
+	}
+
+	ret = gnss_serial_register(gserial);
+	if (ret)
+		goto err_disable_vbackup;
+
+	return 0;
+
+err_disable_vbackup:
+	if (data->vbackup)
+		regulator_disable(data->vbackup);
+err_free_gserial:
+	gnss_serial_free(gserial);
+
+	return ret;
+}
+
+static void mtk_remove(struct serdev_device *serdev)
+{
+	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
+	struct mtk_data *data = gnss_serial_get_drvdata(gserial);
+
+	gnss_serial_deregister(gserial);
+	if (data->vbackup)
+		regulator_disable(data->vbackup);
+	gnss_serial_free(gserial);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id mtk_of_match[] = {
+	{ .compatible = "globaltop,pa6h" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_of_match);
+#endif
+
+static struct serdev_device_driver mtk_driver = {
+	.driver	= {
+		.name		= "gnss-mtk",
+		.of_match_table	= of_match_ptr(mtk_of_match),
+		.pm		= &gnss_serial_pm_ops,
+	},
+	.probe	= mtk_probe,
+	.remove	= mtk_remove,
+};
+module_serdev_device_driver(mtk_driver);
+
+MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>");
+MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gnss/serial.c b/drivers/gnss/serial.c
new file mode 100644
index 000000000..5d8e9bfb2
--- /dev/null
+++ b/drivers/gnss/serial.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic serial GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/sched.h>
+#include <linux/serdev.h>
+#include <linux/slab.h>
+
+#include "serial.h"
+
+static int gnss_serial_open(struct gnss_device *gdev)
+{
+	struct gnss_serial *gserial = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = gserial->serdev;
+	int ret;
+
+	ret = serdev_device_open(serdev);
+	if (ret)
+		return ret;
+
+	serdev_device_set_baudrate(serdev, gserial->speed);
+	serdev_device_set_flow_control(serdev, false);
+
+	ret = pm_runtime_get_sync(&serdev->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&serdev->dev);
+		goto err_close;
+	}
+
+	return 0;
+
+err_close:
+	serdev_device_close(serdev);
+
+	return ret;
+}
+
+static void gnss_serial_close(struct gnss_device *gdev)
+{
+	struct gnss_serial *gserial = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = gserial->serdev;
+
+	serdev_device_close(serdev);
+
+	pm_runtime_put(&serdev->dev);
+}
+
+static int gnss_serial_write_raw(struct gnss_device *gdev,
+		const unsigned char *buf, size_t count)
+{
+	struct gnss_serial *gserial = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = gserial->serdev;
+	int ret;
+
+	/* write is only buffered synchronously */
+	ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT);
+	if (ret < 0 || ret < count)
+		return ret;
+
+	/* FIXME: determine if interrupted? */
+	serdev_device_wait_until_sent(serdev, 0);
+
+	return count;
+}
+
+static const struct gnss_operations gnss_serial_gnss_ops = {
+	.open		= gnss_serial_open,
+	.close		= gnss_serial_close,
+	.write_raw	= gnss_serial_write_raw,
+};
+
+static int gnss_serial_receive_buf(struct serdev_device *serdev,
+					const unsigned char *buf, size_t count)
+{
+	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
+	struct gnss_device *gdev = gserial->gdev;
+
+	return gnss_insert_raw(gdev, buf, count);
+}
+
+static const struct serdev_device_ops gnss_serial_serdev_ops = {
+	.receive_buf	= gnss_serial_receive_buf,
+	.write_wakeup	= serdev_device_write_wakeup,
+};
+
+static int gnss_serial_set_power(struct gnss_serial *gserial,
+					enum gnss_serial_pm_state state)
+{
+	if (!gserial->ops || !gserial->ops->set_power)
+		return 0;
+
+	return gserial->ops->set_power(gserial, state);
+}
+
+/*
+ * FIXME: need to provide subdriver defaults or separate dt parsing from
+ * allocation.
+ */
+static int gnss_serial_parse_dt(struct serdev_device *serdev)
+{
+	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
+	struct device_node *node = serdev->dev.of_node;
+	u32 speed = 4800;
+
+	of_property_read_u32(node, "current-speed", &speed);
+
+	gserial->speed = speed;
+
+	return 0;
+}
+
+struct gnss_serial *gnss_serial_allocate(struct serdev_device *serdev,
+						size_t data_size)
+{
+	struct gnss_serial *gserial;
+	struct gnss_device *gdev;
+	int ret;
+
+	gserial = kzalloc(sizeof(*gserial) + data_size, GFP_KERNEL);
+	if (!gserial)
+		return ERR_PTR(-ENOMEM);
+
+	gdev = gnss_allocate_device(&serdev->dev);
+	if (!gdev) {
+		ret = -ENOMEM;
+		goto err_free_gserial;
+	}
+
+	gdev->ops = &gnss_serial_gnss_ops;
+	gnss_set_drvdata(gdev, gserial);
+
+	gserial->serdev = serdev;
+	gserial->gdev = gdev;
+
+	serdev_device_set_drvdata(serdev, gserial);
+	serdev_device_set_client_ops(serdev, &gnss_serial_serdev_ops);
+
+	ret = gnss_serial_parse_dt(serdev);
+	if (ret)
+		goto err_put_device;
+
+	return gserial;
+
+err_put_device:
+	gnss_put_device(gserial->gdev);
+err_free_gserial:
+	kfree(gserial);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(gnss_serial_allocate);
+
+void gnss_serial_free(struct gnss_serial *gserial)
+{
+	gnss_put_device(gserial->gdev);
+	kfree(gserial);
+}
+EXPORT_SYMBOL_GPL(gnss_serial_free);
+
+int gnss_serial_register(struct gnss_serial *gserial)
+{
+	struct serdev_device *serdev = gserial->serdev;
+	int ret;
+
+	if (IS_ENABLED(CONFIG_PM)) {
+		pm_runtime_enable(&serdev->dev);
+	} else {
+		ret = gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = gnss_register_device(gserial->gdev);
+	if (ret)
+		goto err_disable_rpm;
+
+	return 0;
+
+err_disable_rpm:
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(&serdev->dev);
+	else
+		gnss_serial_set_power(gserial, GNSS_SERIAL_OFF);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gnss_serial_register);
+
+void gnss_serial_deregister(struct gnss_serial *gserial)
+{
+	struct serdev_device *serdev = gserial->serdev;
+
+	gnss_deregister_device(gserial->gdev);
+
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(&serdev->dev);
+	else
+		gnss_serial_set_power(gserial, GNSS_SERIAL_OFF);
+}
+EXPORT_SYMBOL_GPL(gnss_serial_deregister);
+
+#ifdef CONFIG_PM
+static int gnss_serial_runtime_suspend(struct device *dev)
+{
+	struct gnss_serial *gserial = dev_get_drvdata(dev);
+
+	return gnss_serial_set_power(gserial, GNSS_SERIAL_STANDBY);
+}
+
+static int gnss_serial_runtime_resume(struct device *dev)
+{
+	struct gnss_serial *gserial = dev_get_drvdata(dev);
+
+	return gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);
+}
+#endif /* CONFIG_PM */
+
+static int gnss_serial_prepare(struct device *dev)
+{
+	if (pm_runtime_suspended(dev))
+		return 1;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int gnss_serial_suspend(struct device *dev)
+{
+	struct gnss_serial *gserial = dev_get_drvdata(dev);
+	int ret = 0;
+
+	/*
+	 * FIXME: serdev currently lacks support for managing the underlying
+	 * device's wakeup settings. A workaround would be to close the serdev
+	 * device here if it is open.
+	 */
+
+	if (!pm_runtime_suspended(dev))
+		ret = gnss_serial_set_power(gserial, GNSS_SERIAL_STANDBY);
+
+	return ret;
+}
+
+static int gnss_serial_resume(struct device *dev)
+{
+	struct gnss_serial *gserial = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (!pm_runtime_suspended(dev))
+		ret = gnss_serial_set_power(gserial, GNSS_SERIAL_ACTIVE);
+
+	return ret;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+const struct dev_pm_ops gnss_serial_pm_ops = {
+	.prepare	= gnss_serial_prepare,
+	SET_SYSTEM_SLEEP_PM_OPS(gnss_serial_suspend, gnss_serial_resume)
+	SET_RUNTIME_PM_OPS(gnss_serial_runtime_suspend, gnss_serial_runtime_resume, NULL)
+};
+EXPORT_SYMBOL_GPL(gnss_serial_pm_ops);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("Generic serial GNSS receiver driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gnss/serial.h b/drivers/gnss/serial.h
new file mode 100644
index 000000000..621953f78
--- /dev/null
+++ b/drivers/gnss/serial.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generic serial GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#ifndef _LINUX_GNSS_SERIAL_H
+#define _LINUX_GNSS_SERIAL_H
+
+#include <asm/termbits.h>
+#include <linux/pm.h>
+
+struct gnss_serial {
+	struct serdev_device *serdev;
+	struct gnss_device *gdev;
+	speed_t	speed;
+	const struct gnss_serial_ops *ops;
+	unsigned long drvdata[];
+};
+
+enum gnss_serial_pm_state {
+	GNSS_SERIAL_OFF,
+	GNSS_SERIAL_ACTIVE,
+	GNSS_SERIAL_STANDBY,
+};
+
+struct gnss_serial_ops {
+	int (*set_power)(struct gnss_serial *gserial,
+				enum gnss_serial_pm_state state);
+};
+
+extern const struct dev_pm_ops gnss_serial_pm_ops;
+
+struct gnss_serial *gnss_serial_allocate(struct serdev_device *gserial,
+						size_t data_size);
+void gnss_serial_free(struct gnss_serial *gserial);
+
+int gnss_serial_register(struct gnss_serial *gserial);
+void gnss_serial_deregister(struct gnss_serial *gserial);
+
+static inline void *gnss_serial_get_drvdata(struct gnss_serial *gserial)
+{
+	return gserial->drvdata;
+}
+
+#endif /* _LINUX_GNSS_SERIAL_H */
diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c
new file mode 100644
index 000000000..bcb53ccfe
--- /dev/null
+++ b/drivers/gnss/sirf.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SiRFstar GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+#include <linux/sched.h>
+#include <linux/serdev.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#define SIRF_BOOT_DELAY			500
+#define SIRF_ON_OFF_PULSE_TIME		100
+#define SIRF_ACTIVATE_TIMEOUT		200
+#define SIRF_HIBERNATE_TIMEOUT		200
+/*
+ * If no data arrives for this time, we assume that the chip is off.
+ * REVISIT: The report cycle is configurable and can be several minutes long,
+ * so this will only work reliably if the report cycle is set to a reasonable
+ * low value. Also power saving settings (like send data only on movement)
+ * might things work even worse.
+ * Workaround might be to parse shutdown or bootup messages.
+ */
+#define SIRF_REPORT_CYCLE	2000
+
+struct sirf_data {
+	struct gnss_device *gdev;
+	struct serdev_device *serdev;
+	speed_t	speed;
+	struct regulator *vcc;
+	struct regulator *lna;
+	struct gpio_desc *on_off;
+	struct gpio_desc *wakeup;
+	int irq;
+	bool active;
+
+	struct mutex gdev_mutex;
+	bool open;
+
+	struct mutex serdev_mutex;
+	int serdev_count;
+
+	wait_queue_head_t power_wait;
+};
+
+static int sirf_serdev_open(struct sirf_data *data)
+{
+	int ret = 0;
+
+	mutex_lock(&data->serdev_mutex);
+	if (++data->serdev_count == 1) {
+		ret = serdev_device_open(data->serdev);
+		if (ret) {
+			data->serdev_count--;
+			goto out_unlock;
+		}
+
+		serdev_device_set_baudrate(data->serdev, data->speed);
+		serdev_device_set_flow_control(data->serdev, false);
+	}
+
+out_unlock:
+	mutex_unlock(&data->serdev_mutex);
+
+	return ret;
+}
+
+static void sirf_serdev_close(struct sirf_data *data)
+{
+	mutex_lock(&data->serdev_mutex);
+	if (--data->serdev_count == 0)
+		serdev_device_close(data->serdev);
+	mutex_unlock(&data->serdev_mutex);
+}
+
+static int sirf_open(struct gnss_device *gdev)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+	int ret;
+
+	mutex_lock(&data->gdev_mutex);
+	data->open = true;
+	mutex_unlock(&data->gdev_mutex);
+
+	ret = sirf_serdev_open(data);
+	if (ret) {
+		mutex_lock(&data->gdev_mutex);
+		data->open = false;
+		mutex_unlock(&data->gdev_mutex);
+		return ret;
+	}
+
+	ret = pm_runtime_get_sync(&serdev->dev);
+	if (ret < 0) {
+		dev_err(&gdev->dev, "failed to runtime resume: %d\n", ret);
+		pm_runtime_put_noidle(&serdev->dev);
+		goto err_close;
+	}
+
+	return 0;
+
+err_close:
+	sirf_serdev_close(data);
+
+	mutex_lock(&data->gdev_mutex);
+	data->open = false;
+	mutex_unlock(&data->gdev_mutex);
+
+	return ret;
+}
+
+static void sirf_close(struct gnss_device *gdev)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+
+	sirf_serdev_close(data);
+
+	pm_runtime_put(&serdev->dev);
+
+	mutex_lock(&data->gdev_mutex);
+	data->open = false;
+	mutex_unlock(&data->gdev_mutex);
+}
+
+static int sirf_write_raw(struct gnss_device *gdev, const unsigned char *buf,
+				size_t count)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+	int ret;
+
+	/* write is only buffered synchronously */
+	ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT);
+	if (ret < 0 || ret < count)
+		return ret;
+
+	/* FIXME: determine if interrupted? */
+	serdev_device_wait_until_sent(serdev, 0);
+
+	return count;
+}
+
+static const struct gnss_operations sirf_gnss_ops = {
+	.open		= sirf_open,
+	.close		= sirf_close,
+	.write_raw	= sirf_write_raw,
+};
+
+static int sirf_receive_buf(struct serdev_device *serdev,
+				const unsigned char *buf, size_t count)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+	struct gnss_device *gdev = data->gdev;
+	int ret = 0;
+
+	if (!data->wakeup && !data->active) {
+		data->active = true;
+		wake_up_interruptible(&data->power_wait);
+	}
+
+	mutex_lock(&data->gdev_mutex);
+	if (data->open)
+		ret = gnss_insert_raw(gdev, buf, count);
+	mutex_unlock(&data->gdev_mutex);
+
+	return ret;
+}
+
+static const struct serdev_device_ops sirf_serdev_ops = {
+	.receive_buf	= sirf_receive_buf,
+	.write_wakeup	= serdev_device_write_wakeup,
+};
+
+static irqreturn_t sirf_wakeup_handler(int irq, void *dev_id)
+{
+	struct sirf_data *data = dev_id;
+	struct device *dev = &data->serdev->dev;
+	int ret;
+
+	ret = gpiod_get_value_cansleep(data->wakeup);
+	dev_dbg(dev, "%s - wakeup = %d\n", __func__, ret);
+	if (ret < 0)
+		goto out;
+
+	data->active = ret;
+	wake_up_interruptible(&data->power_wait);
+out:
+	return IRQ_HANDLED;
+}
+
+static int sirf_wait_for_power_state_nowakeup(struct sirf_data *data,
+						bool active,
+						unsigned long timeout)
+{
+	int ret;
+
+	/* Wait for state change (including any shutdown messages). */
+	msleep(timeout);
+
+	/* Wait for data reception or timeout. */
+	data->active = false;
+	ret = wait_event_interruptible_timeout(data->power_wait,
+			data->active, msecs_to_jiffies(SIRF_REPORT_CYCLE));
+	if (ret < 0)
+		return ret;
+
+	if (ret > 0 && !active)
+		return -ETIMEDOUT;
+
+	if (ret == 0 && active)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int sirf_wait_for_power_state(struct sirf_data *data, bool active,
+					unsigned long timeout)
+{
+	int ret;
+
+	if (!data->wakeup)
+		return sirf_wait_for_power_state_nowakeup(data, active, timeout);
+
+	ret = wait_event_interruptible_timeout(data->power_wait,
+			data->active == active, msecs_to_jiffies(timeout));
+	if (ret < 0)
+		return ret;
+
+	if (ret == 0) {
+		dev_warn(&data->serdev->dev, "timeout waiting for active state = %d\n",
+				active);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static void sirf_pulse_on_off(struct sirf_data *data)
+{
+	gpiod_set_value_cansleep(data->on_off, 1);
+	msleep(SIRF_ON_OFF_PULSE_TIME);
+	gpiod_set_value_cansleep(data->on_off, 0);
+}
+
+static int sirf_set_active(struct sirf_data *data, bool active)
+{
+	unsigned long timeout;
+	int retries = 3;
+	int ret;
+
+	if (active)
+		timeout = SIRF_ACTIVATE_TIMEOUT;
+	else
+		timeout = SIRF_HIBERNATE_TIMEOUT;
+
+	if (!data->wakeup) {
+		ret = sirf_serdev_open(data);
+		if (ret)
+			return ret;
+	}
+
+	do {
+		sirf_pulse_on_off(data);
+		ret = sirf_wait_for_power_state(data, active, timeout);
+	} while (ret == -ETIMEDOUT && retries--);
+
+	if (!data->wakeup)
+		sirf_serdev_close(data);
+
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int sirf_runtime_suspend(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret2;
+	int ret;
+
+	if (data->on_off)
+		ret = sirf_set_active(data, false);
+	else
+		ret = regulator_disable(data->vcc);
+
+	if (ret)
+		return ret;
+
+	ret = regulator_disable(data->lna);
+	if (ret)
+		goto err_reenable;
+
+	return 0;
+
+err_reenable:
+	if (data->on_off)
+		ret2 = sirf_set_active(data, true);
+	else
+		ret2 = regulator_enable(data->vcc);
+
+	if (ret2)
+		dev_err(dev,
+			"failed to reenable power on failed suspend: %d\n",
+			ret2);
+
+	return ret;
+}
+
+static int sirf_runtime_resume(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = regulator_enable(data->lna);
+	if (ret)
+		return ret;
+
+	if (data->on_off)
+		ret = sirf_set_active(data, true);
+	else
+		ret = regulator_enable(data->vcc);
+
+	if (ret)
+		goto err_disable_lna;
+
+	return 0;
+
+err_disable_lna:
+	regulator_disable(data->lna);
+
+	return ret;
+}
+
+static int __maybe_unused sirf_suspend(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (!pm_runtime_suspended(dev))
+		ret = sirf_runtime_suspend(dev);
+
+	if (data->wakeup)
+		disable_irq(data->irq);
+
+	return ret;
+}
+
+static int __maybe_unused sirf_resume(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (data->wakeup)
+		enable_irq(data->irq);
+
+	if (!pm_runtime_suspended(dev))
+		ret = sirf_runtime_resume(dev);
+
+	return ret;
+}
+
+static const struct dev_pm_ops sirf_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sirf_suspend, sirf_resume)
+	SET_RUNTIME_PM_OPS(sirf_runtime_suspend, sirf_runtime_resume, NULL)
+};
+
+static int sirf_parse_dt(struct serdev_device *serdev)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+	struct device_node *node = serdev->dev.of_node;
+	u32 speed = 9600;
+
+	of_property_read_u32(node, "current-speed", &speed);
+
+	data->speed = speed;
+
+	return 0;
+}
+
+static int sirf_probe(struct serdev_device *serdev)
+{
+	struct device *dev = &serdev->dev;
+	struct gnss_device *gdev;
+	struct sirf_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	gdev = gnss_allocate_device(dev);
+	if (!gdev)
+		return -ENOMEM;
+
+	gdev->type = GNSS_TYPE_SIRF;
+	gdev->ops = &sirf_gnss_ops;
+	gnss_set_drvdata(gdev, data);
+
+	data->serdev = serdev;
+	data->gdev = gdev;
+
+	mutex_init(&data->gdev_mutex);
+	mutex_init(&data->serdev_mutex);
+	init_waitqueue_head(&data->power_wait);
+
+	serdev_device_set_drvdata(serdev, data);
+	serdev_device_set_client_ops(serdev, &sirf_serdev_ops);
+
+	ret = sirf_parse_dt(serdev);
+	if (ret)
+		goto err_put_device;
+
+	data->vcc = devm_regulator_get(dev, "vcc");
+	if (IS_ERR(data->vcc)) {
+		ret = PTR_ERR(data->vcc);
+		goto err_put_device;
+	}
+
+	data->lna = devm_regulator_get(dev, "lna");
+	if (IS_ERR(data->lna)) {
+		ret = PTR_ERR(data->lna);
+		goto err_put_device;
+	}
+
+	data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
+			GPIOD_OUT_LOW);
+	if (IS_ERR(data->on_off)) {
+		ret = PTR_ERR(data->on_off);
+		goto err_put_device;
+	}
+
+	if (data->on_off) {
+		data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup",
+				GPIOD_IN);
+		if (IS_ERR(data->wakeup)) {
+			ret = PTR_ERR(data->wakeup);
+			goto err_put_device;
+		}
+
+		ret = regulator_enable(data->vcc);
+		if (ret)
+			goto err_put_device;
+
+		/* Wait for chip to boot into hibernate mode. */
+		msleep(SIRF_BOOT_DELAY);
+	}
+
+	if (data->wakeup) {
+		ret = gpiod_get_value_cansleep(data->wakeup);
+		if (ret < 0)
+			goto err_disable_vcc;
+		data->active = ret;
+
+		ret = gpiod_to_irq(data->wakeup);
+		if (ret < 0)
+			goto err_disable_vcc;
+		data->irq = ret;
+
+		ret = request_threaded_irq(data->irq, NULL, sirf_wakeup_handler,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				"wakeup", data);
+		if (ret)
+			goto err_disable_vcc;
+	}
+
+	if (data->on_off) {
+		if (!data->wakeup) {
+			data->active = false;
+
+			ret = sirf_serdev_open(data);
+			if (ret)
+				goto err_disable_vcc;
+
+			msleep(SIRF_REPORT_CYCLE);
+			sirf_serdev_close(data);
+		}
+
+		/* Force hibernate mode if already active. */
+		if (data->active) {
+			ret = sirf_set_active(data, false);
+			if (ret) {
+				dev_err(dev, "failed to set hibernate mode: %d\n",
+						ret);
+				goto err_free_irq;
+			}
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_PM)) {
+		pm_runtime_set_suspended(dev);	/* clear runtime_error flag */
+		pm_runtime_enable(dev);
+	} else {
+		ret = sirf_runtime_resume(dev);
+		if (ret < 0)
+			goto err_free_irq;
+	}
+
+	ret = gnss_register_device(gdev);
+	if (ret)
+		goto err_disable_rpm;
+
+	return 0;
+
+err_disable_rpm:
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(dev);
+	else
+		sirf_runtime_suspend(dev);
+err_free_irq:
+	if (data->wakeup)
+		free_irq(data->irq, data);
+err_disable_vcc:
+	if (data->on_off)
+		regulator_disable(data->vcc);
+err_put_device:
+	gnss_put_device(data->gdev);
+
+	return ret;
+}
+
+static void sirf_remove(struct serdev_device *serdev)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+
+	gnss_deregister_device(data->gdev);
+
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(&serdev->dev);
+	else
+		sirf_runtime_suspend(&serdev->dev);
+
+	if (data->wakeup)
+		free_irq(data->irq, data);
+
+	if (data->on_off)
+		regulator_disable(data->vcc);
+
+	gnss_put_device(data->gdev);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id sirf_of_match[] = {
+	{ .compatible = "fastrax,uc430" },
+	{ .compatible = "linx,r4" },
+	{ .compatible = "wi2wi,w2sg0004" },
+	{ .compatible = "wi2wi,w2sg0008i" },
+	{ .compatible = "wi2wi,w2sg0084i" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sirf_of_match);
+#endif
+
+static struct serdev_device_driver sirf_driver = {
+	.driver	= {
+		.name		= "gnss-sirf",
+		.of_match_table	= of_match_ptr(sirf_of_match),
+		.pm		= &sirf_pm_ops,
+	},
+	.probe	= sirf_probe,
+	.remove	= sirf_remove,
+};
+module_serdev_device_driver(sirf_driver);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("SiRFstar GNSS receiver driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gnss/ubx.c b/drivers/gnss/ubx.c
new file mode 100644
index 000000000..c951be202
--- /dev/null
+++ b/drivers/gnss/ubx.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * u-blox GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+#include <linux/serdev.h>
+
+#include "serial.h"
+
+struct ubx_data {
+	struct regulator *v_bckp;
+	struct regulator *vcc;
+};
+
+static int ubx_set_active(struct gnss_serial *gserial)
+{
+	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
+	int ret;
+
+	ret = regulator_enable(data->vcc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ubx_set_standby(struct gnss_serial *gserial)
+{
+	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
+	int ret;
+
+	ret = regulator_disable(data->vcc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ubx_set_power(struct gnss_serial *gserial,
+				enum gnss_serial_pm_state state)
+{
+	switch (state) {
+	case GNSS_SERIAL_ACTIVE:
+		return ubx_set_active(gserial);
+	case GNSS_SERIAL_OFF:
+	case GNSS_SERIAL_STANDBY:
+		return ubx_set_standby(gserial);
+	}
+
+	return -EINVAL;
+}
+
+static const struct gnss_serial_ops ubx_gserial_ops = {
+	.set_power = ubx_set_power,
+};
+
+static int ubx_probe(struct serdev_device *serdev)
+{
+	struct gnss_serial *gserial;
+	struct ubx_data *data;
+	int ret;
+
+	gserial = gnss_serial_allocate(serdev, sizeof(*data));
+	if (IS_ERR(gserial)) {
+		ret = PTR_ERR(gserial);
+		return ret;
+	}
+
+	gserial->ops = &ubx_gserial_ops;
+
+	gserial->gdev->type = GNSS_TYPE_UBX;
+
+	data = gnss_serial_get_drvdata(gserial);
+
+	data->vcc = devm_regulator_get(&serdev->dev, "vcc");
+	if (IS_ERR(data->vcc)) {
+		ret = PTR_ERR(data->vcc);
+		goto err_free_gserial;
+	}
+
+	data->v_bckp = devm_regulator_get_optional(&serdev->dev, "v-bckp");
+	if (IS_ERR(data->v_bckp)) {
+		ret = PTR_ERR(data->v_bckp);
+		if (ret == -ENODEV)
+			data->v_bckp = NULL;
+		else
+			goto err_free_gserial;
+	}
+
+	if (data->v_bckp) {
+		ret = regulator_enable(data->v_bckp);
+		if (ret)
+			goto err_free_gserial;
+	}
+
+	ret = gnss_serial_register(gserial);
+	if (ret)
+		goto err_disable_v_bckp;
+
+	return 0;
+
+err_disable_v_bckp:
+	if (data->v_bckp)
+		regulator_disable(data->v_bckp);
+err_free_gserial:
+	gnss_serial_free(gserial);
+
+	return ret;
+}
+
+static void ubx_remove(struct serdev_device *serdev)
+{
+	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
+	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
+
+	gnss_serial_deregister(gserial);
+	if (data->v_bckp)
+		regulator_disable(data->v_bckp);
+	gnss_serial_free(gserial);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id ubx_of_match[] = {
+	{ .compatible = "u-blox,neo-6m" },
+	{ .compatible = "u-blox,neo-8" },
+	{ .compatible = "u-blox,neo-m8" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ubx_of_match);
+#endif
+
+static struct serdev_device_driver ubx_driver = {
+	.driver	= {
+		.name		= "gnss-ubx",
+		.of_match_table	= of_match_ptr(ubx_of_match),
+		.pm		= &gnss_serial_pm_ops,
+	},
+	.probe	= ubx_probe,
+	.remove	= ubx_remove,
+};
+module_serdev_device_driver(ubx_driver);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("u-blox GNSS receiver driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gnss/usb.c b/drivers/gnss/usb.c
new file mode 100644
index 000000000..028ce56b2
--- /dev/null
+++ b/drivers/gnss/usb.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic USB GNSS receiver driver
+ *
+ * Copyright (C) 2021 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#define GNSS_USB_READ_BUF_LEN	512
+#define GNSS_USB_WRITE_TIMEOUT	1000
+
+static const struct usb_device_id gnss_usb_id_table[] = {
+	{ USB_DEVICE(0x1199, 0xb000) },		/* Sierra Wireless XM1210 */
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, gnss_usb_id_table);
+
+struct gnss_usb {
+	struct usb_device *udev;
+	struct usb_interface *intf;
+	struct gnss_device *gdev;
+	struct urb *read_urb;
+	unsigned int write_pipe;
+};
+
+static void gnss_usb_rx_complete(struct urb *urb)
+{
+	struct gnss_usb *gusb = urb->context;
+	struct gnss_device *gdev = gusb->gdev;
+	int status = urb->status;
+	int len;
+	int ret;
+
+	switch (status) {
+	case 0:
+		break;
+	case -ENOENT:
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+		dev_dbg(&gdev->dev, "urb stopped: %d\n", status);
+		return;
+	case -EPIPE:
+		dev_err(&gdev->dev, "urb stopped: %d\n", status);
+		return;
+	default:
+		dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status);
+		goto resubmit;
+	}
+
+	len = urb->actual_length;
+	if (len == 0)
+		goto resubmit;
+
+	ret = gnss_insert_raw(gdev, urb->transfer_buffer, len);
+	if (ret < len)
+		dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret);
+resubmit:
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret && ret != -EPERM && ret != -ENODEV)
+		dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret);
+}
+
+static int gnss_usb_open(struct gnss_device *gdev)
+{
+	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
+	int ret;
+
+	ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL);
+	if (ret) {
+		if (ret != -EPERM && ret != -ENODEV)
+			dev_err(&gdev->dev, "failed to submit urb: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void gnss_usb_close(struct gnss_device *gdev)
+{
+	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
+
+	usb_kill_urb(gusb->read_urb);
+}
+
+static int gnss_usb_write_raw(struct gnss_device *gdev,
+		const unsigned char *buf, size_t count)
+{
+	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
+	void *tbuf;
+	int ret;
+
+	tbuf = kmemdup(buf, count, GFP_KERNEL);
+	if (!tbuf)
+		return -ENOMEM;
+
+	ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL,
+			GNSS_USB_WRITE_TIMEOUT);
+	kfree(tbuf);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static const struct gnss_operations gnss_usb_gnss_ops = {
+	.open		= gnss_usb_open,
+	.close		= gnss_usb_close,
+	.write_raw	= gnss_usb_write_raw,
+};
+
+static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *in, *out;
+	struct gnss_device *gdev;
+	struct gnss_usb *gusb;
+	struct urb *urb;
+	size_t buf_len;
+	void *buf;
+	int ret;
+
+	ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL,
+			NULL);
+	if (ret)
+		return ret;
+
+	gusb = kzalloc(sizeof(*gusb), GFP_KERNEL);
+	if (!gusb)
+		return -ENOMEM;
+
+	gdev = gnss_allocate_device(&intf->dev);
+	if (!gdev) {
+		ret = -ENOMEM;
+		goto err_free_gusb;
+	}
+
+	gdev->ops = &gnss_usb_gnss_ops;
+	gdev->type = GNSS_TYPE_NMEA;
+	gnss_set_drvdata(gdev, gusb);
+
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb) {
+		ret = -ENOMEM;
+		goto err_put_gdev;
+	}
+
+	buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN);
+
+	buf = kzalloc(buf_len, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto err_free_urb;
+	}
+
+	usb_fill_bulk_urb(urb, udev,
+			usb_rcvbulkpipe(udev, usb_endpoint_num(in)),
+			buf, buf_len, gnss_usb_rx_complete, gusb);
+
+	gusb->intf = intf;
+	gusb->udev = udev;
+	gusb->gdev = gdev;
+	gusb->read_urb = urb;
+	gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out));
+
+	ret = gnss_register_device(gdev);
+	if (ret)
+		goto err_free_buf;
+
+	usb_set_intfdata(intf, gusb);
+
+	return 0;
+
+err_free_buf:
+	kfree(buf);
+err_free_urb:
+	usb_free_urb(urb);
+err_put_gdev:
+	gnss_put_device(gdev);
+err_free_gusb:
+	kfree(gusb);
+
+	return ret;
+}
+
+static void gnss_usb_disconnect(struct usb_interface *intf)
+{
+	struct gnss_usb *gusb = usb_get_intfdata(intf);
+
+	gnss_deregister_device(gusb->gdev);
+
+	kfree(gusb->read_urb->transfer_buffer);
+	usb_free_urb(gusb->read_urb);
+	gnss_put_device(gusb->gdev);
+	kfree(gusb);
+}
+
+static struct usb_driver gnss_usb_driver = {
+	.name		= "gnss-usb",
+	.probe		= gnss_usb_probe,
+	.disconnect	= gnss_usb_disconnect,
+	.id_table	= gnss_usb_id_table,
+};
+module_usb_driver(gnss_usb_driver);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("Generic USB GNSS receiver driver");
+MODULE_LICENSE("GPL v2");