drivers/watchdog/bd70528_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (C) 2018 ROHM Semiconductors
 // ROHM BD70528MWV watchdog driver

 #include <linux/bcd.h>
 #include <linux/kernel.h>
 #include <linux/mfd/rohm-bd70528.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/watchdog.h>

 /*
  * Max time we can set is 1 hour, 59 minutes and 59 seconds
  * and Minimum time is 1 second
  */
 #define WDT_MAX_MS	((2 * 60 * 60 - 1) * 1000)
 #define WDT_MIN_MS	1000
 #define DEFAULT_TIMEOUT	60

 #define WD_CTRL_MAGIC1 0x55
 #define WD_CTRL_MAGIC2 0xAA

 struct wdtbd70528 {
 	struct device *dev;
 	struct regmap *regmap;
 	struct rohm_regmap_dev *mfd;
 	struct watchdog_device wdt;
 };

 /**
  * bd70528_wdt_set - arm or disarm watchdog timer
  *
  * @data:	device data for the PMIC instance we want to operate on
  * @enable:	new state of WDT. zero to disable, non zero to enable
  * @old_state:	previous state of WDT will be filled here
  *
  * Arm or disarm WDT on BD70528 PMIC. Expected to be called only by
  * BD70528 RTC and BD70528 WDT drivers. The rtc_timer_lock must be taken
  * by calling bd70528_wdt_lock before calling bd70528_wdt_set.
  */
 int bd70528_wdt_set(struct rohm_regmap_dev *data, int enable, int *old_state)
 {
 	int ret, i;
 	unsigned int tmp;
 	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
 						 chip);
 	u8 wd_ctrl_arr[3] = { WD_CTRL_MAGIC1, WD_CTRL_MAGIC2, 0 };
 	u8 *wd_ctrl = &wd_ctrl_arr[2];

 	ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
 	if (ret)
 		return ret;

 	*wd_ctrl = (u8)tmp;

 	if (old_state) {
 		if (*wd_ctrl & BD70528_MASK_WDT_EN)
 			*old_state |= BD70528_WDT_STATE_BIT;
 		else
 			*old_state &= ~BD70528_WDT_STATE_BIT;
 		if ((!enable) == (!(*old_state & BD70528_WDT_STATE_BIT)))
 			return 0;
 	}

 	if (enable) {
 		if (*wd_ctrl & BD70528_MASK_WDT_EN)
 			return 0;
 		*wd_ctrl |= BD70528_MASK_WDT_EN;
 	} else {
 		if (*wd_ctrl & BD70528_MASK_WDT_EN)
 			*wd_ctrl &= ~BD70528_MASK_WDT_EN;
 		else
 			return 0;
 	}

 	for (i = 0; i < 3; i++) {
 		ret = regmap_write(bd70528->chip.regmap, BD70528_REG_WDT_CTRL,
 				   wd_ctrl_arr[i]);
 		if (ret)
 			return ret;
 	}

 	ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
 	if ((tmp & BD70528_MASK_WDT_EN) != (*wd_ctrl & BD70528_MASK_WDT_EN)) {
 		dev_err(bd70528->chip.dev,
 			"Watchdog ctrl mismatch (hw) 0x%x (set) 0x%x\n",
 			tmp, *wd_ctrl);
 		ret = -EIO;
 	}

 	return ret;
 }
 EXPORT_SYMBOL(bd70528_wdt_set);

 /**
  * bd70528_wdt_lock - take WDT lock
  *
  * @bd70528:	device data for the PMIC instance we want to operate on
  *
  * Lock WDT for arming/disarming in order to avoid race condition caused
  * by WDT state changes initiated by WDT and RTC drivers.
  */
 void bd70528_wdt_lock(struct rohm_regmap_dev *data)
 {
 	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
 						 chip);

 	mutex_lock(&bd70528->rtc_timer_lock);
 }
 EXPORT_SYMBOL(bd70528_wdt_lock);

 /**
  * bd70528_wdt_unlock - unlock WDT lock
  *
  * @bd70528:	device data for the PMIC instance we want to operate on
  *
  * Unlock WDT lock which has previously been taken by call to
  * bd70528_wdt_lock.
  */
 void bd70528_wdt_unlock(struct rohm_regmap_dev *data)
 {
 	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
 						 chip);

 	mutex_unlock(&bd70528->rtc_timer_lock);
 }
 EXPORT_SYMBOL(bd70528_wdt_unlock);

 static int bd70528_wdt_set_locked(struct wdtbd70528 *w, int enable)
 {
 	return bd70528_wdt_set(w->mfd, enable, NULL);
 }

 static int bd70528_wdt_change(struct wdtbd70528 *w, int enable)
 {
 	int ret;

 	bd70528_wdt_lock(w->mfd);
 	ret = bd70528_wdt_set_locked(w, enable);
 	bd70528_wdt_unlock(w->mfd);

 	return ret;
 }

 static int bd70528_wdt_start(struct watchdog_device *wdt)
 {
 	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

 	dev_dbg(w->dev, "WDT ping...\n");
 	return bd70528_wdt_change(w, 1);
 }

 static int bd70528_wdt_stop(struct watchdog_device *wdt)
 {
 	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

 	dev_dbg(w->dev, "WDT stopping...\n");
 	return bd70528_wdt_change(w, 0);
 }

 static int bd70528_wdt_set_timeout(struct watchdog_device *wdt,
 				   unsigned int timeout)
 {
 	unsigned int hours;
 	unsigned int minutes;
 	unsigned int seconds;
 	int ret;
 	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

 	seconds = timeout;
 	hours = timeout / (60 * 60);
 	/* Maximum timeout is 1h 59m 59s => hours is 1 or 0 */
 	if (hours)
 		seconds -= (60 * 60);
 	minutes = seconds / 60;
 	seconds = seconds % 60;

 	bd70528_wdt_lock(w->mfd);

 	ret = bd70528_wdt_set_locked(w, 0);
 	if (ret)
 		goto out_unlock;

 	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_HOUR,
 				 BD70528_MASK_WDT_HOUR, hours);
 	if (ret) {
 		dev_err(w->dev, "Failed to set WDT hours\n");
 		goto out_en_unlock;
 	}
 	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_MINUTE,
 				 BD70528_MASK_WDT_MINUTE, bin2bcd(minutes));
 	if (ret) {
 		dev_err(w->dev, "Failed to set WDT minutes\n");
 		goto out_en_unlock;
 	}
 	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_SEC,
 				 BD70528_MASK_WDT_SEC, bin2bcd(seconds));
 	if (ret)
 		dev_err(w->dev, "Failed to set WDT seconds\n");
 	else
 		dev_dbg(w->dev, "WDT tmo set to %u\n", timeout);

 out_en_unlock:
 	ret = bd70528_wdt_set_locked(w, 1);
 out_unlock:
 	bd70528_wdt_unlock(w->mfd);

 	return ret;
 }

 static const struct watchdog_info bd70528_wdt_info = {
 	.identity = "bd70528-wdt",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 };

 static const struct watchdog_ops bd70528_wdt_ops = {
 	.start		= bd70528_wdt_start,
 	.stop		= bd70528_wdt_stop,
 	.set_timeout	= bd70528_wdt_set_timeout,
 };

 static int bd70528_wdt_probe(struct platform_device *pdev)
 {
 	struct rohm_regmap_dev *bd70528;
 	struct wdtbd70528 *w;
 	int ret;
 	unsigned int reg;

 	bd70528 = dev_get_drvdata(pdev->dev.parent);
 	if (!bd70528) {
 		dev_err(&pdev->dev, "No MFD driver data\n");
 		return -EINVAL;
 	}
 	w = devm_kzalloc(&pdev->dev, sizeof(*w), GFP_KERNEL);
 	if (!w)
 		return -ENOMEM;

 	w->regmap = bd70528->regmap;
 	w->mfd = bd70528;
 	w->dev = &pdev->dev;

 	w->wdt.info = &bd70528_wdt_info;
 	w->wdt.ops =  &bd70528_wdt_ops;
 	w->wdt.min_hw_heartbeat_ms = WDT_MIN_MS;
 	w->wdt.max_hw_heartbeat_ms = WDT_MAX_MS;
 	w->wdt.parent = pdev->dev.parent;
 	w->wdt.timeout = DEFAULT_TIMEOUT;
 	watchdog_set_drvdata(&w->wdt, w);
 	watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent);

 	ret = bd70528_wdt_set_timeout(&w->wdt, w->wdt.timeout);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to set the watchdog timeout\n");
 		return ret;
 	}

 	bd70528_wdt_lock(w->mfd);
 	ret = regmap_read(w->regmap, BD70528_REG_WDT_CTRL, &reg);
 	bd70528_wdt_unlock(w->mfd);

 	if (ret) {
 		dev_err(&pdev->dev, "Failed to get the watchdog state\n");
 		return ret;
 	}
 	if (reg & BD70528_MASK_WDT_EN) {
 		dev_dbg(&pdev->dev, "watchdog was running during probe\n");
 		set_bit(WDOG_HW_RUNNING, &w->wdt.status);
 	}

 	ret = devm_watchdog_register_device(&pdev->dev, &w->wdt);
 	if (ret < 0)
 		dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);

 	return ret;
 }

 static struct platform_driver bd70528_wdt = {
 	.driver = {
 		.name = "bd70528-wdt"
 	},
 	.probe = bd70528_wdt_probe,
 };

 module_platform_driver(bd70528_wdt);

 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 MODULE_DESCRIPTION("BD70528 watchdog driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (C) 2018 ROHM Semiconductors
	// ROHM BD70528MWV watchdog driver

	#include <linux/bcd.h>
	#include <linux/kernel.h>
	#include <linux/mfd/rohm-bd70528.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/watchdog.h>

	/*
	* Max time we can set is 1 hour, 59 minutes and 59 seconds
	* and Minimum time is 1 second
	*/
	#define WDT_MAX_MS ((2 * 60 * 60 - 1) * 1000)
	#define WDT_MIN_MS 1000
	#define DEFAULT_TIMEOUT 60

	#define WD_CTRL_MAGIC1 0x55
	#define WD_CTRL_MAGIC2 0xAA

	struct wdtbd70528 {
	struct device *dev;
	struct regmap *regmap;
	struct rohm_regmap_dev *mfd;
	struct watchdog_device wdt;
	};

	/**
	* bd70528_wdt_set - arm or disarm watchdog timer
	*
	* @data: device data for the PMIC instance we want to operate on
	* @enable: new state of WDT. zero to disable, non zero to enable
	* @old_state: previous state of WDT will be filled here
	*
	* Arm or disarm WDT on BD70528 PMIC. Expected to be called only by
	* BD70528 RTC and BD70528 WDT drivers. The rtc_timer_lock must be taken
	* by calling bd70528_wdt_lock before calling bd70528_wdt_set.
	*/
	int bd70528_wdt_set(struct rohm_regmap_dev data, int enable, int old_state)
	{
	int ret, i;
	unsigned int tmp;
	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
	chip);
	u8 wd_ctrl_arr[3] = { WD_CTRL_MAGIC1, WD_CTRL_MAGIC2, 0 };
	u8 *wd_ctrl = &wd_ctrl_arr[2];

	ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
	if (ret)
	return ret;

	*wd_ctrl = (u8)tmp;

	if (old_state) {
	if (*wd_ctrl & BD70528_MASK_WDT_EN)
	*old_state \|= BD70528_WDT_STATE_BIT;
	else
	*old_state &= ~BD70528_WDT_STATE_BIT;
	if ((!enable) == (!(*old_state & BD70528_WDT_STATE_BIT)))
	return 0;
	}

	if (enable) {
	if (*wd_ctrl & BD70528_MASK_WDT_EN)
	return 0;
	*wd_ctrl \|= BD70528_MASK_WDT_EN;
	} else {
	if (*wd_ctrl & BD70528_MASK_WDT_EN)
	*wd_ctrl &= ~BD70528_MASK_WDT_EN;
	else
	return 0;
	}

	for (i = 0; i < 3; i++) {
	ret = regmap_write(bd70528->chip.regmap, BD70528_REG_WDT_CTRL,
	wd_ctrl_arr[i]);
	if (ret)
	return ret;
	}

	ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
	if ((tmp & BD70528_MASK_WDT_EN) != (*wd_ctrl & BD70528_MASK_WDT_EN)) {
	dev_err(bd70528->chip.dev,
	"Watchdog ctrl mismatch (hw) 0x%x (set) 0x%x\n",
	tmp, *wd_ctrl);
	ret = -EIO;
	}

	return ret;
	}
	EXPORT_SYMBOL(bd70528_wdt_set);

	/**
	* bd70528_wdt_lock - take WDT lock
	*
	* @bd70528: device data for the PMIC instance we want to operate on
	*
	* Lock WDT for arming/disarming in order to avoid race condition caused
	* by WDT state changes initiated by WDT and RTC drivers.
	*/
	void bd70528_wdt_lock(struct rohm_regmap_dev *data)
	{
	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
	chip);

	mutex_lock(&bd70528->rtc_timer_lock);
	}
	EXPORT_SYMBOL(bd70528_wdt_lock);

	/**
	* bd70528_wdt_unlock - unlock WDT lock
	*
	* @bd70528: device data for the PMIC instance we want to operate on
	*
	* Unlock WDT lock which has previously been taken by call to
	* bd70528_wdt_lock.
	*/
	void bd70528_wdt_unlock(struct rohm_regmap_dev *data)
	{
	struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
	chip);

	mutex_unlock(&bd70528->rtc_timer_lock);
	}
	EXPORT_SYMBOL(bd70528_wdt_unlock);

	static int bd70528_wdt_set_locked(struct wdtbd70528 *w, int enable)
	{
	return bd70528_wdt_set(w->mfd, enable, NULL);
	}

	static int bd70528_wdt_change(struct wdtbd70528 *w, int enable)
	{
	int ret;

	bd70528_wdt_lock(w->mfd);
	ret = bd70528_wdt_set_locked(w, enable);
	bd70528_wdt_unlock(w->mfd);

	return ret;
	}

	static int bd70528_wdt_start(struct watchdog_device *wdt)
	{
	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

	dev_dbg(w->dev, "WDT ping...\n");
	return bd70528_wdt_change(w, 1);
	}

	static int bd70528_wdt_stop(struct watchdog_device *wdt)
	{
	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

	dev_dbg(w->dev, "WDT stopping...\n");
	return bd70528_wdt_change(w, 0);
	}

	static int bd70528_wdt_set_timeout(struct watchdog_device *wdt,
	unsigned int timeout)
	{
	unsigned int hours;
	unsigned int minutes;
	unsigned int seconds;
	int ret;
	struct wdtbd70528 *w = watchdog_get_drvdata(wdt);

	seconds = timeout;
	hours = timeout / (60 * 60);
	/* Maximum timeout is 1h 59m 59s => hours is 1 or 0 */
	if (hours)
	seconds -= (60 * 60);
	minutes = seconds / 60;
	seconds = seconds % 60;

	bd70528_wdt_lock(w->mfd);

	ret = bd70528_wdt_set_locked(w, 0);
	if (ret)
	goto out_unlock;

	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_HOUR,
	BD70528_MASK_WDT_HOUR, hours);
	if (ret) {
	dev_err(w->dev, "Failed to set WDT hours\n");
	goto out_en_unlock;
	}
	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_MINUTE,
	BD70528_MASK_WDT_MINUTE, bin2bcd(minutes));
	if (ret) {
	dev_err(w->dev, "Failed to set WDT minutes\n");
	goto out_en_unlock;
	}
	ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_SEC,
	BD70528_MASK_WDT_SEC, bin2bcd(seconds));
	if (ret)
	dev_err(w->dev, "Failed to set WDT seconds\n");
	else
	dev_dbg(w->dev, "WDT tmo set to %u\n", timeout);

	out_en_unlock:
	ret = bd70528_wdt_set_locked(w, 1);
	out_unlock:
	bd70528_wdt_unlock(w->mfd);

	return ret;
	}

	static const struct watchdog_info bd70528_wdt_info = {
	.identity = "bd70528-wdt",
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	};

	static const struct watchdog_ops bd70528_wdt_ops = {
	.start = bd70528_wdt_start,
	.stop = bd70528_wdt_stop,
	.set_timeout = bd70528_wdt_set_timeout,
	};

	static int bd70528_wdt_probe(struct platform_device *pdev)
	{
	struct rohm_regmap_dev *bd70528;
	struct wdtbd70528 *w;
	int ret;
	unsigned int reg;

	bd70528 = dev_get_drvdata(pdev->dev.parent);
	if (!bd70528) {
	dev_err(&pdev->dev, "No MFD driver data\n");
	return -EINVAL;
	}
	w = devm_kzalloc(&pdev->dev, sizeof(*w), GFP_KERNEL);
	if (!w)
	return -ENOMEM;

	w->regmap = bd70528->regmap;
	w->mfd = bd70528;
	w->dev = &pdev->dev;

	w->wdt.info = &bd70528_wdt_info;
	w->wdt.ops = &bd70528_wdt_ops;
	w->wdt.min_hw_heartbeat_ms = WDT_MIN_MS;
	w->wdt.max_hw_heartbeat_ms = WDT_MAX_MS;
	w->wdt.parent = pdev->dev.parent;
	w->wdt.timeout = DEFAULT_TIMEOUT;
	watchdog_set_drvdata(&w->wdt, w);
	watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent);

	ret = bd70528_wdt_set_timeout(&w->wdt, w->wdt.timeout);
	if (ret) {
	dev_err(&pdev->dev, "Failed to set the watchdog timeout\n");
	return ret;
	}

	bd70528_wdt_lock(w->mfd);
	ret = regmap_read(w->regmap, BD70528_REG_WDT_CTRL, &reg);
	bd70528_wdt_unlock(w->mfd);

	if (ret) {
	dev_err(&pdev->dev, "Failed to get the watchdog state\n");
	return ret;
	}
	if (reg & BD70528_MASK_WDT_EN) {
	dev_dbg(&pdev->dev, "watchdog was running during probe\n");
	set_bit(WDOG_HW_RUNNING, &w->wdt.status);
	}

	ret = devm_watchdog_register_device(&pdev->dev, &w->wdt);
	if (ret < 0)
	dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);

	return ret;
	}

	static struct platform_driver bd70528_wdt = {
	.driver = {
	.name = "bd70528-wdt"
	},
	.probe = bd70528_wdt_probe,
	};

	module_platform_driver(bd70528_wdt);

	MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
	MODULE_DESCRIPTION("BD70528 watchdog driver");
	MODULE_LICENSE("GPL");