drivers/watchdog/imx2_wdt.c - third_party/linux - Git at Google

 /*
  * Watchdog driver for IMX2 and later processors
  *
  *  Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
  *  Copyright (C) 2014 Freescale Semiconductor, Inc.
  *
  * some parts adapted by similar drivers from Darius Augulis and Vladimir
  * Zapolskiy, additional improvements by Wim Van Sebroeck.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  *
  * NOTE: MX1 has a slightly different Watchdog than MX2 and later:
  *
  *			MX1:		MX2+:
  *			----		-----
  * Registers:		32-bit		16-bit
  * Stopable timer:	Yes		No
  * Need to enable clk:	No		Yes
  * Halt on suspend:	Manual		Can be automatic
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/notifier.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/timer.h>
 #include <linux/watchdog.h>

 #define DRIVER_NAME "imx2-wdt"

 #define IMX2_WDT_WCR		0x00		/* Control Register */
 #define IMX2_WDT_WCR_WT		(0xFF << 8)	/* -> Watchdog Timeout Field */
 #define IMX2_WDT_WCR_WRE	(1 << 3)	/* -> WDOG Reset Enable */
 #define IMX2_WDT_WCR_WDE	(1 << 2)	/* -> Watchdog Enable */
 #define IMX2_WDT_WCR_WDZST	(1 << 0)	/* -> Watchdog timer Suspend */

 #define IMX2_WDT_WSR		0x02		/* Service Register */
 #define IMX2_WDT_SEQ1		0x5555		/* -> service sequence 1 */
 #define IMX2_WDT_SEQ2		0xAAAA		/* -> service sequence 2 */

 #define IMX2_WDT_WRSR		0x04		/* Reset Status Register */
 #define IMX2_WDT_WRSR_TOUT	(1 << 1)	/* -> Reset due to Timeout */

 #define IMX2_WDT_WMCR		0x08		/* Misc Register */

 #define IMX2_WDT_MAX_TIME	128
 #define IMX2_WDT_DEFAULT_TIME	60		/* in seconds */

 #define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)

 struct imx2_wdt_device {
 	struct clk *clk;
 	struct regmap *regmap;
 	struct timer_list timer;	/* Pings the watchdog when closed */
 	struct watchdog_device wdog;
 	struct notifier_block restart_handler;
 };

 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 timeout = IMX2_WDT_DEFAULT_TIME;
 module_param(timeout, uint, 0);
 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
 				__MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");

 static const struct watchdog_info imx2_wdt_info = {
 	.identity = "imx2+ watchdog",
 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 };

 static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
 				void *cmd)
 {
 	unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
 	struct imx2_wdt_device *wdev = container_of(this,
 						    struct imx2_wdt_device,
 						    restart_handler);
 	/* Assert SRS signal */
 	regmap_write(wdev->regmap, 0, wcr_enable);
 	/*
 	 * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
 	 * written twice), we add another two writes to ensure there must be at
 	 * least two writes happen in the same one 32kHz clock period.  We save
 	 * the target check here, since the writes shouldn't be a huge burden
 	 * for other platforms.
 	 */
 	regmap_write(wdev->regmap, 0, wcr_enable);
 	regmap_write(wdev->regmap, 0, wcr_enable);

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

 	return NOTIFY_DONE;
 }

 static inline void imx2_wdt_setup(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 	u32 val;

 	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);

 	/* Suspend timer in low power mode, write once-only */
 	val |= IMX2_WDT_WCR_WDZST;
 	/* Strip the old watchdog Time-Out value */
 	val &= ~IMX2_WDT_WCR_WT;
 	/* Generate reset if WDOG times out */
 	val &= ~IMX2_WDT_WCR_WRE;
 	/* Keep Watchdog Disabled */
 	val &= ~IMX2_WDT_WCR_WDE;
 	/* Set the watchdog's Time-Out value */
 	val |= WDOG_SEC_TO_COUNT(wdog->timeout);

 	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);

 	/* enable the watchdog */
 	val |= IMX2_WDT_WCR_WDE;
 	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
 }

 static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
 {
 	u32 val;

 	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);

 	return val & IMX2_WDT_WCR_WDE;
 }

 static int imx2_wdt_ping(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
 	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
 	return 0;
 }

 static void imx2_wdt_timer_ping(unsigned long arg)
 {
 	struct watchdog_device *wdog = (struct watchdog_device *)arg;
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	/* ping it every wdog->timeout / 2 seconds to prevent reboot */
 	imx2_wdt_ping(wdog);
 	mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
 }

 static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int new_timeout)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
 			   WDOG_SEC_TO_COUNT(new_timeout));
 	return 0;
 }

 static int imx2_wdt_start(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	if (imx2_wdt_is_running(wdev)) {
 		/* delete the timer that pings the watchdog after close */
 		del_timer_sync(&wdev->timer);
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 	} else
 		imx2_wdt_setup(wdog);

 	return imx2_wdt_ping(wdog);
 }

 static int imx2_wdt_stop(struct watchdog_device *wdog)
 {
 	/*
 	 * We don't need a clk_disable, it cannot be disabled once started.
 	 * We use a timer to ping the watchdog while /dev/watchdog is closed
 	 */
 	imx2_wdt_timer_ping((unsigned long)wdog);
 	return 0;
 }

 static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 		imx2_wdt_timer_ping((unsigned long)wdog);
 	}
 }

 static const struct watchdog_ops imx2_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx2_wdt_start,
 	.stop = imx2_wdt_stop,
 	.ping = imx2_wdt_ping,
 	.set_timeout = imx2_wdt_set_timeout,
 };

 static const struct regmap_config imx2_wdt_regmap_config = {
 	.reg_bits = 16,
 	.reg_stride = 2,
 	.val_bits = 16,
 	.max_register = 0x8,
 };

 static int __init imx2_wdt_probe(struct platform_device *pdev)
 {
 	struct imx2_wdt_device *wdev;
 	struct watchdog_device *wdog;
 	struct resource *res;
 	void __iomem *base;
 	int ret;
 	u32 val;

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

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(base))
 		return PTR_ERR(base);

 	wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
 						 &imx2_wdt_regmap_config);
 	if (IS_ERR(wdev->regmap)) {
 		dev_err(&pdev->dev, "regmap init failed\n");
 		return PTR_ERR(wdev->regmap);
 	}

 	wdev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(wdev->clk)) {
 		dev_err(&pdev->dev, "can't get Watchdog clock\n");
 		return PTR_ERR(wdev->clk);
 	}

 	wdog			= &wdev->wdog;
 	wdog->info		= &imx2_wdt_info;
 	wdog->ops		= &imx2_wdt_ops;
 	wdog->min_timeout	= 1;
 	wdog->max_timeout	= IMX2_WDT_MAX_TIME;

 	clk_prepare_enable(wdev->clk);

 	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
 	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;

 	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
 	if (wdog->timeout != timeout)
 		dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",
 			 timeout, wdog->timeout);

 	platform_set_drvdata(pdev, wdog);
 	watchdog_set_drvdata(wdog, wdev);
 	watchdog_set_nowayout(wdog, nowayout);
 	watchdog_init_timeout(wdog, timeout, &pdev->dev);

 	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);

 	imx2_wdt_ping_if_active(wdog);

 	/*
 	 * Disable the watchdog power down counter at boot. Otherwise the power
 	 * down counter will pull down the #WDOG interrupt line for one clock
 	 * cycle.
 	 */
 	regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0);

 	ret = watchdog_register_device(wdog);
 	if (ret) {
 		dev_err(&pdev->dev, "cannot register watchdog device\n");
 		return ret;
 	}

 	wdev->restart_handler.notifier_call = imx2_restart_handler;
 	wdev->restart_handler.priority = 128;
 	ret = register_restart_handler(&wdev->restart_handler);
 	if (ret)
 		dev_err(&pdev->dev, "cannot register restart handler\n");

 	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
 		 wdog->timeout, nowayout);

 	return 0;
 }

 static int __exit imx2_wdt_remove(struct platform_device *pdev)
 {
 	struct watchdog_device *wdog = platform_get_drvdata(pdev);
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	unregister_restart_handler(&wdev->restart_handler);

 	watchdog_unregister_device(wdog);

 	if (imx2_wdt_is_running(wdev)) {
 		del_timer_sync(&wdev->timer);
 		imx2_wdt_ping(wdog);
 		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
 	}
 	return 0;
 }

 static void imx2_wdt_shutdown(struct platform_device *pdev)
 {
 	struct watchdog_device *wdog = platform_get_drvdata(pdev);
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	if (imx2_wdt_is_running(wdev)) {
 		/*
 		 * We are running, we need to delete the timer but will
 		 * give max timeout before reboot will take place
 		 */
 		del_timer_sync(&wdev->timer);
 		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
 		imx2_wdt_ping(wdog);
 		dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
 	}
 }

 #ifdef CONFIG_PM_SLEEP
 /* Disable watchdog if it is active or non-active but still running */
 static int imx2_wdt_suspend(struct device *dev)
 {
 	struct watchdog_device *wdog = dev_get_drvdata(dev);
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	/* The watchdog IP block is running */
 	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
 		imx2_wdt_ping(wdog);

 		/* The watchdog is not active */
 		if (!watchdog_active(wdog))
 			del_timer_sync(&wdev->timer);
 	}

 	clk_disable_unprepare(wdev->clk);

 	return 0;
 }

 /* Enable watchdog and configure it if necessary */
 static int imx2_wdt_resume(struct device *dev)
 {
 	struct watchdog_device *wdog = dev_get_drvdata(dev);
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

 	clk_prepare_enable(wdev->clk);

 	if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) {
 		/*
 		 * If the watchdog is still active and resumes
 		 * from deep sleep state, need to restart the
 		 * watchdog again.
 		 */
 		imx2_wdt_setup(wdog);
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 		imx2_wdt_ping(wdog);
 	} else if (imx2_wdt_is_running(wdev)) {
 		/* Resuming from non-deep sleep state. */
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 		imx2_wdt_ping(wdog);
 		/*
 		 * But the watchdog is not active, then start
 		 * the timer again.
 		 */
 		if (!watchdog_active(wdog))
 			mod_timer(&wdev->timer,
 				  jiffies + wdog->timeout * HZ / 2);
 	}

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,
 			 imx2_wdt_resume);

 static const struct of_device_id imx2_wdt_dt_ids[] = {
 	{ .compatible = "fsl,imx21-wdt", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);

 static struct platform_driver imx2_wdt_driver = {
 	.remove		= __exit_p(imx2_wdt_remove),
 	.shutdown	= imx2_wdt_shutdown,
 	.driver		= {
 		.name	= DRIVER_NAME,
 		.pm     = &imx2_wdt_pm_ops,
 		.of_match_table = imx2_wdt_dt_ids,
 	},
 };

 module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);

 MODULE_AUTHOR("Wolfram Sang");
 MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:" DRIVER_NAME);
	/*
	* Watchdog driver for IMX2 and later processors
	*
	* Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
	* Copyright (C) 2014 Freescale Semiconductor, Inc.
	*
	* some parts adapted by similar drivers from Darius Augulis and Vladimir
	* Zapolskiy, additional improvements by Wim Van Sebroeck.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*
	* NOTE: MX1 has a slightly different Watchdog than MX2 and later:
	*
	* MX1: MX2+:
	* ---- -----
	* Registers: 32-bit 16-bit
	* Stopable timer: Yes No
	* Need to enable clk: No Yes
	* Halt on suspend: Manual Can be automatic
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/jiffies.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/notifier.h>
	#include <linux/of_address.h>
	#include <linux/platform_device.h>
	#include <linux/reboot.h>
	#include <linux/regmap.h>
	#include <linux/timer.h>
	#include <linux/watchdog.h>

	#define DRIVER_NAME "imx2-wdt"

	#define IMX2_WDT_WCR 0x00 /* Control Register */
	#define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */
	#define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */
	#define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */
	#define IMX2_WDT_WCR_WDZST (1 << 0) /* -> Watchdog timer Suspend */

	#define IMX2_WDT_WSR 0x02 /* Service Register */
	#define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */
	#define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */

	#define IMX2_WDT_WRSR 0x04 /* Reset Status Register */
	#define IMX2_WDT_WRSR_TOUT (1 << 1) /* -> Reset due to Timeout */

	#define IMX2_WDT_WMCR 0x08 /* Misc Register */

	#define IMX2_WDT_MAX_TIME 128
	#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */

	#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)

	struct imx2_wdt_device {
	struct clk *clk;
	struct regmap *regmap;
	struct timer_list timer; /* Pings the watchdog when closed */
	struct watchdog_device wdog;
	struct notifier_block restart_handler;
	};

	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 timeout = IMX2_WDT_DEFAULT_TIME;
	module_param(timeout, uint, 0);
	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
	__MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");

	static const struct watchdog_info imx2_wdt_info = {
	.identity = "imx2+ watchdog",
	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE,
	};

	static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
	void *cmd)
	{
	unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
	struct imx2_wdt_device *wdev = container_of(this,
	struct imx2_wdt_device,
	restart_handler);
	/* Assert SRS signal */
	regmap_write(wdev->regmap, 0, wcr_enable);
	/*
	* Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
	* written twice), we add another two writes to ensure there must be at
	* least two writes happen in the same one 32kHz clock period. We save
	* the target check here, since the writes shouldn't be a huge burden
	* for other platforms.
	*/
	regmap_write(wdev->regmap, 0, wcr_enable);
	regmap_write(wdev->regmap, 0, wcr_enable);

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

	return NOTIFY_DONE;
	}

	static inline void imx2_wdt_setup(struct watchdog_device *wdog)
	{
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
	u32 val;

	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);

	/* Suspend timer in low power mode, write once-only */
	val \|= IMX2_WDT_WCR_WDZST;
	/* Strip the old watchdog Time-Out value */
	val &= ~IMX2_WDT_WCR_WT;
	/* Generate reset if WDOG times out */
	val &= ~IMX2_WDT_WCR_WRE;
	/* Keep Watchdog Disabled */
	val &= ~IMX2_WDT_WCR_WDE;
	/* Set the watchdog's Time-Out value */
	val \|= WDOG_SEC_TO_COUNT(wdog->timeout);

	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);

	/* enable the watchdog */
	val \|= IMX2_WDT_WCR_WDE;
	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
	}

	static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
	{
	u32 val;

	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);

	return val & IMX2_WDT_WCR_WDE;
	}

	static int imx2_wdt_ping(struct watchdog_device *wdog)
	{
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
	return 0;
	}

	static void imx2_wdt_timer_ping(unsigned long arg)
	{
	struct watchdog_device wdog = (struct watchdog_device )arg;
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	/* ping it every wdog->timeout / 2 seconds to prevent reboot */
	imx2_wdt_ping(wdog);
	mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
	}

	static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
	unsigned int new_timeout)
	{
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
	WDOG_SEC_TO_COUNT(new_timeout));
	return 0;
	}

	static int imx2_wdt_start(struct watchdog_device *wdog)
	{
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	if (imx2_wdt_is_running(wdev)) {
	/* delete the timer that pings the watchdog after close */
	del_timer_sync(&wdev->timer);
	imx2_wdt_set_timeout(wdog, wdog->timeout);
	} else
	imx2_wdt_setup(wdog);

	return imx2_wdt_ping(wdog);
	}

	static int imx2_wdt_stop(struct watchdog_device *wdog)
	{
	/*
	* We don't need a clk_disable, it cannot be disabled once started.
	* We use a timer to ping the watchdog while /dev/watchdog is closed
	*/
	imx2_wdt_timer_ping((unsigned long)wdog);
	return 0;
	}

	static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
	{
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	if (imx2_wdt_is_running(wdev)) {
	imx2_wdt_set_timeout(wdog, wdog->timeout);
	imx2_wdt_timer_ping((unsigned long)wdog);
	}
	}

	static const struct watchdog_ops imx2_wdt_ops = {
	.owner = THIS_MODULE,
	.start = imx2_wdt_start,
	.stop = imx2_wdt_stop,
	.ping = imx2_wdt_ping,
	.set_timeout = imx2_wdt_set_timeout,
	};

	static const struct regmap_config imx2_wdt_regmap_config = {
	.reg_bits = 16,
	.reg_stride = 2,
	.val_bits = 16,
	.max_register = 0x8,
	};

	static int __init imx2_wdt_probe(struct platform_device *pdev)
	{
	struct imx2_wdt_device *wdev;
	struct watchdog_device *wdog;
	struct resource *res;
	void __iomem *base;
	int ret;
	u32 val;

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

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(base))
	return PTR_ERR(base);

	wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
	&imx2_wdt_regmap_config);
	if (IS_ERR(wdev->regmap)) {
	dev_err(&pdev->dev, "regmap init failed\n");
	return PTR_ERR(wdev->regmap);
	}

	wdev->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(wdev->clk)) {
	dev_err(&pdev->dev, "can't get Watchdog clock\n");
	return PTR_ERR(wdev->clk);
	}

	wdog = &wdev->wdog;
	wdog->info = &imx2_wdt_info;
	wdog->ops = &imx2_wdt_ops;
	wdog->min_timeout = 1;
	wdog->max_timeout = IMX2_WDT_MAX_TIME;

	clk_prepare_enable(wdev->clk);

	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;

	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
	if (wdog->timeout != timeout)
	dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",
	timeout, wdog->timeout);

	platform_set_drvdata(pdev, wdog);
	watchdog_set_drvdata(wdog, wdev);
	watchdog_set_nowayout(wdog, nowayout);
	watchdog_init_timeout(wdog, timeout, &pdev->dev);

	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);

	imx2_wdt_ping_if_active(wdog);

	/*
	* Disable the watchdog power down counter at boot. Otherwise the power
	* down counter will pull down the #WDOG interrupt line for one clock
	* cycle.
	*/
	regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0);

	ret = watchdog_register_device(wdog);
	if (ret) {
	dev_err(&pdev->dev, "cannot register watchdog device\n");
	return ret;
	}

	wdev->restart_handler.notifier_call = imx2_restart_handler;
	wdev->restart_handler.priority = 128;
	ret = register_restart_handler(&wdev->restart_handler);
	if (ret)
	dev_err(&pdev->dev, "cannot register restart handler\n");

	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
	wdog->timeout, nowayout);

	return 0;
	}

	static int __exit imx2_wdt_remove(struct platform_device *pdev)
	{
	struct watchdog_device *wdog = platform_get_drvdata(pdev);
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	unregister_restart_handler(&wdev->restart_handler);

	watchdog_unregister_device(wdog);

	if (imx2_wdt_is_running(wdev)) {
	del_timer_sync(&wdev->timer);
	imx2_wdt_ping(wdog);
	dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
	}
	return 0;
	}

	static void imx2_wdt_shutdown(struct platform_device *pdev)
	{
	struct watchdog_device *wdog = platform_get_drvdata(pdev);
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	if (imx2_wdt_is_running(wdev)) {
	/*
	* We are running, we need to delete the timer but will
	* give max timeout before reboot will take place
	*/
	del_timer_sync(&wdev->timer);
	imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
	imx2_wdt_ping(wdog);
	dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
	}
	}

	#ifdef CONFIG_PM_SLEEP
	/* Disable watchdog if it is active or non-active but still running */
	static int imx2_wdt_suspend(struct device *dev)
	{
	struct watchdog_device *wdog = dev_get_drvdata(dev);
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	/* The watchdog IP block is running */
	if (imx2_wdt_is_running(wdev)) {
	imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
	imx2_wdt_ping(wdog);

	/* The watchdog is not active */
	if (!watchdog_active(wdog))
	del_timer_sync(&wdev->timer);
	}

	clk_disable_unprepare(wdev->clk);

	return 0;
	}

	/* Enable watchdog and configure it if necessary */
	static int imx2_wdt_resume(struct device *dev)
	{
	struct watchdog_device *wdog = dev_get_drvdata(dev);
	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

	clk_prepare_enable(wdev->clk);

	if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) {
	/*
	* If the watchdog is still active and resumes
	* from deep sleep state, need to restart the
	* watchdog again.
	*/
	imx2_wdt_setup(wdog);
	imx2_wdt_set_timeout(wdog, wdog->timeout);
	imx2_wdt_ping(wdog);
	} else if (imx2_wdt_is_running(wdev)) {
	/* Resuming from non-deep sleep state. */
	imx2_wdt_set_timeout(wdog, wdog->timeout);
	imx2_wdt_ping(wdog);
	/*
	* But the watchdog is not active, then start
	* the timer again.
	*/
	if (!watchdog_active(wdog))
	mod_timer(&wdev->timer,
	jiffies + wdog->timeout * HZ / 2);
	}

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,
	imx2_wdt_resume);

	static const struct of_device_id imx2_wdt_dt_ids[] = {
	{ .compatible = "fsl,imx21-wdt", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);

	static struct platform_driver imx2_wdt_driver = {
	.remove = __exit_p(imx2_wdt_remove),
	.shutdown = imx2_wdt_shutdown,
	.driver = {
	.name = DRIVER_NAME,
	.pm = &imx2_wdt_pm_ops,
	.of_match_table = imx2_wdt_dt_ids,
	},
	};

	module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);

	MODULE_AUTHOR("Wolfram Sang");
	MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:" DRIVER_NAME);