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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * omap_wdt.c
  *
  * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
  *
  * Author: MontaVista Software, Inc.
  *	 <gdavis@mvista.com> or <source@mvista.com>
  *
  * 2003 (c) MontaVista Software, Inc.
  *
  * History:
  *
  * 20030527: George G. Davis <gdavis@mvista.com>
  *	Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
  *	(c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  *	Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
  *
  * Copyright (c) 2004 Texas Instruments.
  *	1. Modified to support OMAP1610 32-KHz watchdog timer
  *	2. Ported to 2.6 kernel
  *
  * Copyright (c) 2005 David Brownell
  *	Use the driver model and standard identifiers; handle bigger timeouts.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/watchdog.h>
 #include <linux/reboot.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/moduleparam.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/pm_runtime.h>
 #include <linux/platform_data/omap-wd-timer.h>

 #include "omap_wdt.h"

 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 static unsigned timer_margin;
 module_param(timer_margin, uint, 0);
 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");

 #define to_omap_wdt_dev(_wdog)	container_of(_wdog, struct omap_wdt_dev, wdog)

 static bool early_enable;
 module_param(early_enable, bool, 0);
 MODULE_PARM_DESC(early_enable,
 	"Watchdog is started on module insertion (default=0)");

 struct omap_wdt_dev {
 	struct watchdog_device wdog;
 	void __iomem    *base;          /* physical */
 	struct device   *dev;
 	bool		omap_wdt_users;
 	int		wdt_trgr_pattern;
 	struct mutex	lock;		/* to avoid races with PM */
 };

 static void omap_wdt_reload(struct omap_wdt_dev *wdev)
 {
 	void __iomem    *base = wdev->base;

 	/* wait for posted write to complete */
 	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
 		cpu_relax();

 	wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern;
 	writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));

 	/* wait for posted write to complete */
 	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
 		cpu_relax();
 	/* reloaded WCRR from WLDR */
 }

 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
 {
 	void __iomem *base = wdev->base;

 	/* Sequence to enable the watchdog */
 	writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR);
 	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
 		cpu_relax();

 	writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR);
 	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
 		cpu_relax();
 }

 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 {
 	void __iomem *base = wdev->base;

 	/* sequence required to disable watchdog */
 	writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
 		cpu_relax();

 	writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
 		cpu_relax();
 }

 static void omap_wdt_set_timer(struct omap_wdt_dev *wdev,
 				   unsigned int timeout)
 {
 	u32 pre_margin = GET_WLDR_VAL(timeout);
 	void __iomem *base = wdev->base;

 	/* just count up at 32 KHz */
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
 		cpu_relax();

 	writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR);
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
 		cpu_relax();
 }

 static int omap_wdt_start(struct watchdog_device *wdog)
 {
 	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 	void __iomem *base = wdev->base;

 	mutex_lock(&wdev->lock);

 	wdev->omap_wdt_users = true;

 	pm_runtime_get_sync(wdev->dev);

 	/*
 	 * Make sure the watchdog is disabled. This is unfortunately required
 	 * because writing to various registers with the watchdog running has no
 	 * effect.
 	 */
 	omap_wdt_disable(wdev);

 	/* initialize prescaler */
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
 		cpu_relax();

 	writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
 		cpu_relax();

 	omap_wdt_set_timer(wdev, wdog->timeout);
 	omap_wdt_reload(wdev); /* trigger loading of new timeout value */
 	omap_wdt_enable(wdev);

 	mutex_unlock(&wdev->lock);

 	return 0;
 }

 static int omap_wdt_stop(struct watchdog_device *wdog)
 {
 	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

 	mutex_lock(&wdev->lock);
 	omap_wdt_disable(wdev);
 	pm_runtime_put_sync(wdev->dev);
 	wdev->omap_wdt_users = false;
 	mutex_unlock(&wdev->lock);
 	return 0;
 }

 static int omap_wdt_ping(struct watchdog_device *wdog)
 {
 	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

 	mutex_lock(&wdev->lock);
 	omap_wdt_reload(wdev);
 	mutex_unlock(&wdev->lock);

 	return 0;
 }

 static int omap_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int timeout)
 {
 	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

 	mutex_lock(&wdev->lock);
 	omap_wdt_disable(wdev);
 	omap_wdt_set_timer(wdev, timeout);
 	omap_wdt_enable(wdev);
 	omap_wdt_reload(wdev);
 	wdog->timeout = timeout;
 	mutex_unlock(&wdev->lock);

 	return 0;
 }

 static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog)
 {
 	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 	void __iomem *base = wdev->base;
 	u32 value;

 	value = readl_relaxed(base + OMAP_WATCHDOG_CRR);
 	return GET_WCCR_SECS(value);
 }

 static const struct watchdog_info omap_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 	.identity = "OMAP Watchdog",
 };

 static const struct watchdog_ops omap_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= omap_wdt_start,
 	.stop		= omap_wdt_stop,
 	.ping		= omap_wdt_ping,
 	.set_timeout	= omap_wdt_set_timeout,
 	.get_timeleft	= omap_wdt_get_timeleft,
 };

 static int omap_wdt_probe(struct platform_device *pdev)
 {
 	struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct omap_wdt_dev *wdev;
 	int ret;

 	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
 	if (!wdev)
 		return -ENOMEM;

 	wdev->omap_wdt_users	= false;
 	wdev->dev		= &pdev->dev;
 	wdev->wdt_trgr_pattern	= 0x1234;
 	mutex_init(&wdev->lock);

 	/* reserve static register mappings */
 	wdev->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(wdev->base))
 		return PTR_ERR(wdev->base);

 	wdev->wdog.info = &omap_wdt_info;
 	wdev->wdog.ops = &omap_wdt_ops;
 	wdev->wdog.min_timeout = TIMER_MARGIN_MIN;
 	wdev->wdog.max_timeout = TIMER_MARGIN_MAX;
 	wdev->wdog.timeout = TIMER_MARGIN_DEFAULT;
 	wdev->wdog.parent = &pdev->dev;

 	watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev);

 	watchdog_set_nowayout(&wdev->wdog, nowayout);

 	platform_set_drvdata(pdev, wdev);

 	pm_runtime_enable(wdev->dev);
 	pm_runtime_get_sync(wdev->dev);

 	if (pdata && pdata->read_reset_sources) {
 		u32 rs = pdata->read_reset_sources();
 		if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT))
 			wdev->wdog.bootstatus = WDIOF_CARDRESET;
 	}

 	if (early_enable) {
 		omap_wdt_start(&wdev->wdog);
 		set_bit(WDOG_HW_RUNNING, &wdev->wdog.status);
 	} else {
 		omap_wdt_disable(wdev);
 	}

 	ret = watchdog_register_device(&wdev->wdog);
 	if (ret) {
 		pm_runtime_put(wdev->dev);
 		pm_runtime_disable(wdev->dev);
 		return ret;
 	}

 	pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 		readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 		wdev->wdog.timeout);

 	if (early_enable)
 		omap_wdt_start(&wdev->wdog);

 	pm_runtime_put(wdev->dev);

 	return 0;
 }

 static void omap_wdt_shutdown(struct platform_device *pdev)
 {
 	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

 	mutex_lock(&wdev->lock);
 	if (wdev->omap_wdt_users) {
 		omap_wdt_disable(wdev);
 		pm_runtime_put_sync(wdev->dev);
 	}
 	mutex_unlock(&wdev->lock);
 }

 static void omap_wdt_remove(struct platform_device *pdev)
 {
 	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

 	pm_runtime_disable(wdev->dev);
 	watchdog_unregister_device(&wdev->wdog);
 }

 /* REVISIT ... not clear this is the best way to handle system suspend; and
  * it's very inappropriate for selective device suspend (e.g. suspending this
  * through sysfs rather than by stopping the watchdog daemon).  Also, this
  * may not play well enough with NOWAYOUT...
  */

 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

 	mutex_lock(&wdev->lock);
 	if (wdev->omap_wdt_users) {
 		omap_wdt_disable(wdev);
 		pm_runtime_put_sync(wdev->dev);
 	}
 	mutex_unlock(&wdev->lock);

 	return 0;
 }

 static int omap_wdt_resume(struct platform_device *pdev)
 {
 	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

 	mutex_lock(&wdev->lock);
 	if (wdev->omap_wdt_users) {
 		pm_runtime_get_sync(wdev->dev);
 		omap_wdt_enable(wdev);
 		omap_wdt_reload(wdev);
 	}
 	mutex_unlock(&wdev->lock);

 	return 0;
 }

 static const struct of_device_id omap_wdt_of_match[] = {
 	{ .compatible = "ti,omap3-wdt", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);

 static struct platform_driver omap_wdt_driver = {
 	.probe		= omap_wdt_probe,
 	.remove_new	= omap_wdt_remove,
 	.shutdown	= omap_wdt_shutdown,
 	.suspend	= pm_ptr(omap_wdt_suspend),
 	.resume		= pm_ptr(omap_wdt_resume),
 	.driver		= {
 		.name	= "omap_wdt",
 		.of_match_table = omap_wdt_of_match,
 	},
 };

 module_platform_driver(omap_wdt_driver);

 MODULE_AUTHOR("George G. Davis");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:omap_wdt");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* omap_wdt.c
	*
	* Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
	*
	* Author: MontaVista Software, Inc.
	* <gdavis@mvista.com> or <source@mvista.com>
	*
	* 2003 (c) MontaVista Software, Inc.
	*
	* History:
	*
	* 20030527: George G. Davis <gdavis@mvista.com>
	* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
	* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
	* Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
	*
	* Copyright (c) 2004 Texas Instruments.
	* 1. Modified to support OMAP1610 32-KHz watchdog timer
	* 2. Ported to 2.6 kernel
	*
	* Copyright (c) 2005 David Brownell
	* Use the driver model and standard identifiers; handle bigger timeouts.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/watchdog.h>
	#include <linux/reboot.h>
	#include <linux/err.h>
	#include <linux/platform_device.h>
	#include <linux/moduleparam.h>
	#include <linux/io.h>
	#include <linux/slab.h>
	#include <linux/pm_runtime.h>
	#include <linux/platform_data/omap-wd-timer.h>

	#include "omap_wdt.h"

	static bool nowayout = WATCHDOG_NOWAYOUT;
	module_param(nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	static unsigned timer_margin;
	module_param(timer_margin, uint, 0);
	MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");

	#define to_omap_wdt_dev(_wdog) container_of(_wdog, struct omap_wdt_dev, wdog)

	static bool early_enable;
	module_param(early_enable, bool, 0);
	MODULE_PARM_DESC(early_enable,
	"Watchdog is started on module insertion (default=0)");

	struct omap_wdt_dev {
	struct watchdog_device wdog;
	void __iomem base; / physical */
	struct device *dev;
	bool omap_wdt_users;
	int wdt_trgr_pattern;
	struct mutex lock; /* to avoid races with PM */
	};

	static void omap_wdt_reload(struct omap_wdt_dev *wdev)
	{
	void __iomem *base = wdev->base;

	/* wait for posted write to complete */
	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
	cpu_relax();

	wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern;
	writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));

	/* wait for posted write to complete */
	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
	cpu_relax();
	/* reloaded WCRR from WLDR */
	}

	static void omap_wdt_enable(struct omap_wdt_dev *wdev)
	{
	void __iomem *base = wdev->base;

	/* Sequence to enable the watchdog */
	writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR);
	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
	cpu_relax();

	writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR);
	while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
	cpu_relax();
	}

	static void omap_wdt_disable(struct omap_wdt_dev *wdev)
	{
	void __iomem *base = wdev->base;

	/* sequence required to disable watchdog */
	writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
	cpu_relax();

	writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
	cpu_relax();
	}

	static void omap_wdt_set_timer(struct omap_wdt_dev *wdev,
	unsigned int timeout)
	{
	u32 pre_margin = GET_WLDR_VAL(timeout);
	void __iomem *base = wdev->base;

	/* just count up at 32 KHz */
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
	cpu_relax();

	writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR);
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
	cpu_relax();
	}

	static int omap_wdt_start(struct watchdog_device *wdog)
	{
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
	void __iomem *base = wdev->base;

	mutex_lock(&wdev->lock);

	wdev->omap_wdt_users = true;

	pm_runtime_get_sync(wdev->dev);

	/*
	* Make sure the watchdog is disabled. This is unfortunately required
	* because writing to various registers with the watchdog running has no
	* effect.
	*/
	omap_wdt_disable(wdev);

	/* initialize prescaler */
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
	cpu_relax();

	writel_relaxed((1 << 5) \| (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
	while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
	cpu_relax();

	omap_wdt_set_timer(wdev, wdog->timeout);
	omap_wdt_reload(wdev); /* trigger loading of new timeout value */
	omap_wdt_enable(wdev);

	mutex_unlock(&wdev->lock);

	return 0;
	}

	static int omap_wdt_stop(struct watchdog_device *wdog)
	{
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

	mutex_lock(&wdev->lock);
	omap_wdt_disable(wdev);
	pm_runtime_put_sync(wdev->dev);
	wdev->omap_wdt_users = false;
	mutex_unlock(&wdev->lock);
	return 0;
	}

	static int omap_wdt_ping(struct watchdog_device *wdog)
	{
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

	mutex_lock(&wdev->lock);
	omap_wdt_reload(wdev);
	mutex_unlock(&wdev->lock);

	return 0;
	}

	static int omap_wdt_set_timeout(struct watchdog_device *wdog,
	unsigned int timeout)
	{
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

	mutex_lock(&wdev->lock);
	omap_wdt_disable(wdev);
	omap_wdt_set_timer(wdev, timeout);
	omap_wdt_enable(wdev);
	omap_wdt_reload(wdev);
	wdog->timeout = timeout;
	mutex_unlock(&wdev->lock);

	return 0;
	}

	static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog)
	{
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
	void __iomem *base = wdev->base;
	u32 value;

	value = readl_relaxed(base + OMAP_WATCHDOG_CRR);
	return GET_WCCR_SECS(value);
	}

	static const struct watchdog_info omap_wdt_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING,
	.identity = "OMAP Watchdog",
	};

	static const struct watchdog_ops omap_wdt_ops = {
	.owner = THIS_MODULE,
	.start = omap_wdt_start,
	.stop = omap_wdt_stop,
	.ping = omap_wdt_ping,
	.set_timeout = omap_wdt_set_timeout,
	.get_timeleft = omap_wdt_get_timeleft,
	};

	static int omap_wdt_probe(struct platform_device *pdev)
	{
	struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct omap_wdt_dev *wdev;
	int ret;

	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
	if (!wdev)
	return -ENOMEM;

	wdev->omap_wdt_users = false;
	wdev->dev = &pdev->dev;
	wdev->wdt_trgr_pattern = 0x1234;
	mutex_init(&wdev->lock);

	/* reserve static register mappings */
	wdev->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(wdev->base))
	return PTR_ERR(wdev->base);

	wdev->wdog.info = &omap_wdt_info;
	wdev->wdog.ops = &omap_wdt_ops;
	wdev->wdog.min_timeout = TIMER_MARGIN_MIN;
	wdev->wdog.max_timeout = TIMER_MARGIN_MAX;
	wdev->wdog.timeout = TIMER_MARGIN_DEFAULT;
	wdev->wdog.parent = &pdev->dev;

	watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev);

	watchdog_set_nowayout(&wdev->wdog, nowayout);

	platform_set_drvdata(pdev, wdev);

	pm_runtime_enable(wdev->dev);
	pm_runtime_get_sync(wdev->dev);

	if (pdata && pdata->read_reset_sources) {
	u32 rs = pdata->read_reset_sources();
	if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT))
	wdev->wdog.bootstatus = WDIOF_CARDRESET;
	}

	if (early_enable) {
	omap_wdt_start(&wdev->wdog);
	set_bit(WDOG_HW_RUNNING, &wdev->wdog.status);
	} else {
	omap_wdt_disable(wdev);
	}

	ret = watchdog_register_device(&wdev->wdog);
	if (ret) {
	pm_runtime_put(wdev->dev);
	pm_runtime_disable(wdev->dev);
	return ret;
	}

	pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
	readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
	wdev->wdog.timeout);

	if (early_enable)
	omap_wdt_start(&wdev->wdog);

	pm_runtime_put(wdev->dev);

	return 0;
	}

	static void omap_wdt_shutdown(struct platform_device *pdev)
	{
	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

	mutex_lock(&wdev->lock);
	if (wdev->omap_wdt_users) {
	omap_wdt_disable(wdev);
	pm_runtime_put_sync(wdev->dev);
	}
	mutex_unlock(&wdev->lock);
	}

	static void omap_wdt_remove(struct platform_device *pdev)
	{
	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

	pm_runtime_disable(wdev->dev);
	watchdog_unregister_device(&wdev->wdog);
	}

	/* REVISIT ... not clear this is the best way to handle system suspend; and
	* it's very inappropriate for selective device suspend (e.g. suspending this
	* through sysfs rather than by stopping the watchdog daemon). Also, this
	* may not play well enough with NOWAYOUT...
	*/

	static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
	{
	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

	mutex_lock(&wdev->lock);
	if (wdev->omap_wdt_users) {
	omap_wdt_disable(wdev);
	pm_runtime_put_sync(wdev->dev);
	}
	mutex_unlock(&wdev->lock);

	return 0;
	}

	static int omap_wdt_resume(struct platform_device *pdev)
	{
	struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);

	mutex_lock(&wdev->lock);
	if (wdev->omap_wdt_users) {
	pm_runtime_get_sync(wdev->dev);
	omap_wdt_enable(wdev);
	omap_wdt_reload(wdev);
	}
	mutex_unlock(&wdev->lock);

	return 0;
	}

	static const struct of_device_id omap_wdt_of_match[] = {
	{ .compatible = "ti,omap3-wdt", },
	{},
	};
	MODULE_DEVICE_TABLE(of, omap_wdt_of_match);

	static struct platform_driver omap_wdt_driver = {
	.probe = omap_wdt_probe,
	.remove_new = omap_wdt_remove,
	.shutdown = omap_wdt_shutdown,
	.suspend = pm_ptr(omap_wdt_suspend),
	.resume = pm_ptr(omap_wdt_resume),
	.driver = {
	.name = "omap_wdt",
	.of_match_table = omap_wdt_of_match,
	},
	};

	module_platform_driver(omap_wdt_driver);

	MODULE_AUTHOR("George G. Davis");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:omap_wdt");