drivers/gnss/sirf.c - linux - Git at Google

 // 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

 struct sirf_data {
 	struct gnss_device *gdev;
 	struct serdev_device *serdev;
 	speed_t	speed;
 	struct regulator *vcc;
 	struct gpio_desc *on_off;
 	struct gpio_desc *wakeup;
 	int irq;
 	bool active;
 	wait_queue_head_t power_wait;
 };

 static int sirf_open(struct gnss_device *gdev)
 {
 	struct sirf_data *data = gnss_get_drvdata(gdev);
 	struct serdev_device *serdev = data->serdev;
 	int ret;

 	ret = serdev_device_open(serdev);
 	if (ret)
 		return ret;

 	serdev_device_set_baudrate(serdev, data->speed);
 	serdev_device_set_flow_control(serdev, false);

 	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:
 	serdev_device_close(serdev);

 	return ret;
 }

 static void sirf_close(struct gnss_device *gdev)
 {
 	struct sirf_data *data = gnss_get_drvdata(gdev);
 	struct serdev_device *serdev = data->serdev;

 	serdev_device_close(serdev);

 	pm_runtime_put(&serdev->dev);
 }

 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;

 	return gnss_insert_raw(gdev, buf, count);
 }

 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(struct sirf_data *data, bool active,
 					unsigned long timeout)
 {
 	int ret;

 	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;

 	do {
 		sirf_pulse_on_off(data);
 		ret = sirf_wait_for_power_state(data, active, timeout);
 		if (ret < 0) {
 			if (ret == -ETIMEDOUT)
 				continue;

 			return ret;
 		}

 		break;
 	} while (retries--);

 	if (retries < 0)
 		return -ETIMEDOUT;

 	return 0;
 }

 static int sirf_runtime_suspend(struct device *dev)
 {
 	struct sirf_data *data = dev_get_drvdata(dev);

 	if (!data->on_off)
 		return regulator_disable(data->vcc);

 	return sirf_set_active(data, false);
 }

 static int sirf_runtime_resume(struct device *dev)
 {
 	struct sirf_data *data = dev_get_drvdata(dev);

 	if (!data->on_off)
 		return regulator_enable(data->vcc);

 	return sirf_set_active(data, true);
 }

 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;

 	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->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
 			GPIOD_OUT_LOW);
 	if (IS_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))
 			goto err_put_device;

 		/*
 		 * Configurations where WAKEUP has been left not connected,
 		 * are currently not supported.
 		 */
 		if (!data->wakeup) {
 			dev_err(dev, "no wakeup gpio specified\n");
 			ret = -ENODEV;
 			goto err_put_device;
 		}
 	}

 	if (data->wakeup) {
 		ret = gpiod_to_irq(data->wakeup);
 		if (ret < 0)
 			goto err_put_device;

 		data->irq = ret;

 		ret = devm_request_threaded_irq(dev, data->irq, NULL,
 				sirf_wakeup_handler,
 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 				"wakeup", data);
 		if (ret)
 			goto err_put_device;
 	}

 	if (data->on_off) {
 		ret = regulator_enable(data->vcc);
 		if (ret)
 			goto err_put_device;

 		/* Wait for chip to boot into hibernate mode */
 		msleep(SIRF_BOOT_DELAY);
 	}

 	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_disable_vcc;
 	}

 	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_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->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,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");
	// 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

	struct sirf_data {
	struct gnss_device *gdev;
	struct serdev_device *serdev;
	speed_t speed;
	struct regulator *vcc;
	struct gpio_desc *on_off;
	struct gpio_desc *wakeup;
	int irq;
	bool active;
	wait_queue_head_t power_wait;
	};

	static int sirf_open(struct gnss_device *gdev)
	{
	struct sirf_data *data = gnss_get_drvdata(gdev);
	struct serdev_device *serdev = data->serdev;
	int ret;

	ret = serdev_device_open(serdev);
	if (ret)
	return ret;

	serdev_device_set_baudrate(serdev, data->speed);
	serdev_device_set_flow_control(serdev, false);

	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:
	serdev_device_close(serdev);

	return ret;
	}

	static void sirf_close(struct gnss_device *gdev)
	{
	struct sirf_data *data = gnss_get_drvdata(gdev);
	struct serdev_device *serdev = data->serdev;

	serdev_device_close(serdev);

	pm_runtime_put(&serdev->dev);
	}

	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;

	return gnss_insert_raw(gdev, buf, count);
	}

	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(struct sirf_data *data, bool active,
	unsigned long timeout)
	{
	int ret;

	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;

	do {
	sirf_pulse_on_off(data);
	ret = sirf_wait_for_power_state(data, active, timeout);
	if (ret < 0) {
	if (ret == -ETIMEDOUT)
	continue;

	return ret;
	}

	break;
	} while (retries--);

	if (retries < 0)
	return -ETIMEDOUT;

	return 0;
	}

	static int sirf_runtime_suspend(struct device *dev)
	{
	struct sirf_data *data = dev_get_drvdata(dev);

	if (!data->on_off)
	return regulator_disable(data->vcc);

	return sirf_set_active(data, false);
	}

	static int sirf_runtime_resume(struct device *dev)
	{
	struct sirf_data *data = dev_get_drvdata(dev);

	if (!data->on_off)
	return regulator_enable(data->vcc);

	return sirf_set_active(data, true);
	}

	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;

	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->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
	GPIOD_OUT_LOW);
	if (IS_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))
	goto err_put_device;

	/*
	* Configurations where WAKEUP has been left not connected,
	* are currently not supported.
	*/
	if (!data->wakeup) {
	dev_err(dev, "no wakeup gpio specified\n");
	ret = -ENODEV;
	goto err_put_device;
	}
	}

	if (data->wakeup) {
	ret = gpiod_to_irq(data->wakeup);
	if (ret < 0)
	goto err_put_device;

	data->irq = ret;

	ret = devm_request_threaded_irq(dev, data->irq, NULL,
	sirf_wakeup_handler,
	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING \| IRQF_ONESHOT,
	"wakeup", data);
	if (ret)
	goto err_put_device;
	}

	if (data->on_off) {
	ret = regulator_enable(data->vcc);
	if (ret)
	goto err_put_device;

	/* Wait for chip to boot into hibernate mode */
	msleep(SIRF_BOOT_DELAY);
	}

	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_disable_vcc;
	}

	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_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->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,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");