drivers/watchdog/da9063_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Watchdog driver for DA9063 PMICs.
  *
  * Copyright(c) 2012 Dialog Semiconductor Ltd.
  *
  * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
  *
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/watchdog.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/mfd/da9063/registers.h>
 #include <linux/mfd/da9063/core.h>
 #include <linux/regmap.h>

 /*
  * Watchdog selector to timeout in seconds.
  *   0: WDT disabled;
  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
  */
 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
 #define DA9063_TWDSCALE_DISABLE		0
 #define DA9063_TWDSCALE_MIN		1
 #define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
 #define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
 #define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
 #define DA9063_WDG_TIMEOUT		wdt_timeout[3]
 #define DA9063_RESET_PROTECTION_MS	256

 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
 {
 	unsigned int i;

 	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
 		if (wdt_timeout[i] >= secs)
 			return i;
 	}

 	return DA9063_TWDSCALE_MAX;
 }

 /*
  * Read the currently active timeout.
  * Zero means the watchdog is disabled.
  */
 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
 {
 	unsigned int val;

 	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);

 	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
 }

 static int da9063_wdt_disable_timer(struct da9063 *da9063)
 {
 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
 				  DA9063_TWDSCALE_MASK,
 				  DA9063_TWDSCALE_DISABLE);
 }

 static int
 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
 {
 	unsigned int regval;
 	int ret;

 	/*
 	 * The watchdog triggers a reboot if a timeout value is already
 	 * programmed because the timeout value combines two functions
 	 * in one: indicating the counter limit and starting the watchdog.
 	 * The watchdog must be disabled to be able to change the timeout
 	 * value if the watchdog is already running. Then we can set the
 	 * new timeout value which enables the watchdog again.
 	 */
 	ret = da9063_wdt_disable_timer(da9063);
 	if (ret)
 		return ret;

 	usleep_range(150, 300);
 	regval = da9063_wdt_timeout_to_sel(timeout);

 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
 				  DA9063_TWDSCALE_MASK, regval);
 }

 static int da9063_wdt_start(struct watchdog_device *wdd)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	int ret;

 	ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
 	if (ret)
 		dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
 			ret);

 	return ret;
 }

 static int da9063_wdt_stop(struct watchdog_device *wdd)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	int ret;

 	ret = da9063_wdt_disable_timer(da9063);
 	if (ret)
 		dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
 			  ret);

 	return ret;
 }

 static int da9063_wdt_ping(struct watchdog_device *wdd)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	int ret;

 	/*
 	 * Prevent pings from occurring late in system poweroff/reboot sequence
 	 * and possibly locking out restart handler from accessing i2c bus.
 	 */
 	if (system_state > SYSTEM_RUNNING)
 		return 0;

 	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
 			   DA9063_WATCHDOG);
 	if (ret)
 		dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
 			  ret);

 	return ret;
 }

 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
 				  unsigned int timeout)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	int ret = 0;

 	/*
 	 * There are two cases when a set_timeout() will be called:
 	 * 1. The watchdog is off and someone wants to set the timeout for the
 	 *    further use.
 	 * 2. The watchdog is already running and a new timeout value should be
 	 *    set.
 	 *
 	 * The watchdog can't store a timeout value not equal zero without
 	 * enabling the watchdog, so the timeout must be buffered by the driver.
 	 */
 	if (watchdog_active(wdd))
 		ret = da9063_wdt_update_timeout(da9063, timeout);

 	if (ret)
 		dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
 			ret);
 	else
 		wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];

 	return ret;
 }

 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 			      void *data)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	struct i2c_client *client = to_i2c_client(da9063->dev);
 	int ret;

 	/* Don't use regmap because it is not atomic safe */
 	ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F,
 					DA9063_SHUTDOWN);
 	if (ret < 0)
 		dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
 			  ret);

 	/* wait for reset to assert... */
 	mdelay(500);

 	return ret;
 }

 static const struct watchdog_info da9063_watchdog_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 	.identity = "DA9063 Watchdog",
 };

 static const struct watchdog_ops da9063_watchdog_ops = {
 	.owner = THIS_MODULE,
 	.start = da9063_wdt_start,
 	.stop = da9063_wdt_stop,
 	.ping = da9063_wdt_ping,
 	.set_timeout = da9063_wdt_set_timeout,
 	.restart = da9063_wdt_restart,
 };

 static int da9063_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct da9063 *da9063;
 	struct watchdog_device *wdd;
 	unsigned int timeout;

 	if (!dev->parent)
 		return -EINVAL;

 	da9063 = dev_get_drvdata(dev->parent);
 	if (!da9063)
 		return -EINVAL;

 	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
 	if (!wdd)
 		return -ENOMEM;

 	wdd->info = &da9063_watchdog_info;
 	wdd->ops = &da9063_watchdog_ops;
 	wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
 	wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
 	wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
 	wdd->parent = dev;
 	wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;

 	watchdog_set_restart_priority(wdd, 128);
 	watchdog_set_drvdata(wdd, da9063);

 	wdd->timeout = DA9063_WDG_TIMEOUT;

 	/* Use pre-configured timeout if watchdog is already running. */
 	timeout = da9063_wdt_read_timeout(da9063);
 	if (timeout)
 		wdd->timeout = timeout;

 	/* Set timeout, maybe override it with DT value, scale it */
 	watchdog_init_timeout(wdd, 0, dev);
 	da9063_wdt_set_timeout(wdd, wdd->timeout);

 	/* Update timeout if the watchdog is already running. */
 	if (timeout) {
 		da9063_wdt_update_timeout(da9063, wdd->timeout);
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
 	}

 	return devm_watchdog_register_device(dev, wdd);
 }

 static struct platform_driver da9063_wdt_driver = {
 	.probe = da9063_wdt_probe,
 	.driver = {
 		.name = DA9063_DRVNAME_WATCHDOG,
 	},
 };
 module_platform_driver(da9063_wdt_driver);

 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Watchdog driver for DA9063 PMICs.
	*
	* Copyright(c) 2012 Dialog Semiconductor Ltd.
	*
	* Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
	*
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/watchdog.h>
	#include <linux/platform_device.h>
	#include <linux/uaccess.h>
	#include <linux/slab.h>
	#include <linux/i2c.h>
	#include <linux/delay.h>
	#include <linux/mfd/da9063/registers.h>
	#include <linux/mfd/da9063/core.h>
	#include <linux/regmap.h>

	/*
	* Watchdog selector to timeout in seconds.
	* 0: WDT disabled;
	* others: timeout = 2048 ms * 2^(TWDSCALE-1).
	*/
	static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
	#define DA9063_TWDSCALE_DISABLE 0
	#define DA9063_TWDSCALE_MIN 1
	#define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
	#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
	#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
	#define DA9063_WDG_TIMEOUT wdt_timeout[3]
	#define DA9063_RESET_PROTECTION_MS 256

	static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
	{
	unsigned int i;

	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
	if (wdt_timeout[i] >= secs)
	return i;
	}

	return DA9063_TWDSCALE_MAX;
	}

	/*
	* Read the currently active timeout.
	* Zero means the watchdog is disabled.
	*/
	static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
	{
	unsigned int val;

	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);

	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
	}

	static int da9063_wdt_disable_timer(struct da9063 *da9063)
	{
	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
	DA9063_TWDSCALE_MASK,
	DA9063_TWDSCALE_DISABLE);
	}

	static int
	da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
	{
	unsigned int regval;
	int ret;

	/*
	* The watchdog triggers a reboot if a timeout value is already
	* programmed because the timeout value combines two functions
	* in one: indicating the counter limit and starting the watchdog.
	* The watchdog must be disabled to be able to change the timeout
	* value if the watchdog is already running. Then we can set the
	* new timeout value which enables the watchdog again.
	*/
	ret = da9063_wdt_disable_timer(da9063);
	if (ret)
	return ret;

	usleep_range(150, 300);
	regval = da9063_wdt_timeout_to_sel(timeout);

	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
	DA9063_TWDSCALE_MASK, regval);
	}

	static int da9063_wdt_start(struct watchdog_device *wdd)
	{
	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
	int ret;

	ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
	if (ret)
	dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
	ret);

	return ret;
	}

	static int da9063_wdt_stop(struct watchdog_device *wdd)
	{
	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
	int ret;

	ret = da9063_wdt_disable_timer(da9063);
	if (ret)
	dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
	ret);

	return ret;
	}

	static int da9063_wdt_ping(struct watchdog_device *wdd)
	{
	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
	int ret;

	/*
	* Prevent pings from occurring late in system poweroff/reboot sequence
	* and possibly locking out restart handler from accessing i2c bus.
	*/
	if (system_state > SYSTEM_RUNNING)
	return 0;

	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
	DA9063_WATCHDOG);
	if (ret)
	dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
	ret);

	return ret;
	}

	static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
	unsigned int timeout)
	{
	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
	int ret = 0;

	/*
	* There are two cases when a set_timeout() will be called:
	* 1. The watchdog is off and someone wants to set the timeout for the
	* further use.
	* 2. The watchdog is already running and a new timeout value should be
	* set.
	*
	* The watchdog can't store a timeout value not equal zero without
	* enabling the watchdog, so the timeout must be buffered by the driver.
	*/
	if (watchdog_active(wdd))
	ret = da9063_wdt_update_timeout(da9063, timeout);

	if (ret)
	dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
	ret);
	else
	wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];

	return ret;
	}

	static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
	void *data)
	{
	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
	struct i2c_client *client = to_i2c_client(da9063->dev);
	int ret;

	/* Don't use regmap because it is not atomic safe */
	ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F,
	DA9063_SHUTDOWN);
	if (ret < 0)
	dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
	ret);

	/* wait for reset to assert... */
	mdelay(500);

	return ret;
	}

	static const struct watchdog_info da9063_watchdog_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	.identity = "DA9063 Watchdog",
	};

	static const struct watchdog_ops da9063_watchdog_ops = {
	.owner = THIS_MODULE,
	.start = da9063_wdt_start,
	.stop = da9063_wdt_stop,
	.ping = da9063_wdt_ping,
	.set_timeout = da9063_wdt_set_timeout,
	.restart = da9063_wdt_restart,
	};

	static int da9063_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct da9063 *da9063;
	struct watchdog_device *wdd;
	unsigned int timeout;

	if (!dev->parent)
	return -EINVAL;

	da9063 = dev_get_drvdata(dev->parent);
	if (!da9063)
	return -EINVAL;

	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
	if (!wdd)
	return -ENOMEM;

	wdd->info = &da9063_watchdog_info;
	wdd->ops = &da9063_watchdog_ops;
	wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
	wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
	wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
	wdd->parent = dev;
	wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;

	watchdog_set_restart_priority(wdd, 128);
	watchdog_set_drvdata(wdd, da9063);

	wdd->timeout = DA9063_WDG_TIMEOUT;

	/* Use pre-configured timeout if watchdog is already running. */
	timeout = da9063_wdt_read_timeout(da9063);
	if (timeout)
	wdd->timeout = timeout;

	/* Set timeout, maybe override it with DT value, scale it */
	watchdog_init_timeout(wdd, 0, dev);
	da9063_wdt_set_timeout(wdd, wdd->timeout);

	/* Update timeout if the watchdog is already running. */
	if (timeout) {
	da9063_wdt_update_timeout(da9063, wdd->timeout);
	set_bit(WDOG_HW_RUNNING, &wdd->status);
	}

	return devm_watchdog_register_device(dev, wdd);
	}

	static struct platform_driver da9063_wdt_driver = {
	.probe = da9063_wdt_probe,
	.driver = {
	.name = DA9063_DRVNAME_WATCHDOG,
	},
	};
	module_platform_driver(da9063_wdt_driver);

	MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
	MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);