drivers/watchdog/lpc18xx_wdt.c - kernel/msm-5.4 - Gitiles

 /*
  * NXP LPC18xx Watchdog Timer (WDT)
  *
  * Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
  *
  * 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.
  *
  * Notes
  * -----
  * The Watchdog consists of a fixed divide-by-4 clock pre-scaler and a 24-bit
  * counter which decrements on every clock cycle.
  */

 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>

 /* Registers */
 #define LPC18XX_WDT_MOD			0x00
 #define LPC18XX_WDT_MOD_WDEN		BIT(0)
 #define LPC18XX_WDT_MOD_WDRESET		BIT(1)

 #define LPC18XX_WDT_TC			0x04
 #define LPC18XX_WDT_TC_MIN		0xff
 #define LPC18XX_WDT_TC_MAX		0xffffff

 #define LPC18XX_WDT_FEED		0x08
 #define LPC18XX_WDT_FEED_MAGIC1		0xaa
 #define LPC18XX_WDT_FEED_MAGIC2		0x55

 #define LPC18XX_WDT_TV			0x0c

 /* Clock pre-scaler */
 #define LPC18XX_WDT_CLK_DIV		4

 /* Timeout values in seconds */
 #define LPC18XX_WDT_DEF_TIMEOUT		30U

 static int heartbeat;
 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds (default="
 		 __MODULE_STRING(LPC18XX_WDT_DEF_TIMEOUT) ")");

 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) ")");

 struct lpc18xx_wdt_dev {
 	struct watchdog_device	wdt_dev;
 	struct clk		*reg_clk;
 	struct clk		*wdt_clk;
 	unsigned long		clk_rate;
 	void __iomem		*base;
 	struct timer_list	timer;
 	spinlock_t		lock;
 };

 static int lpc18xx_wdt_feed(struct watchdog_device *wdt_dev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
 	unsigned long flags;

 	/*
 	 * An abort condition will occur if an interrupt happens during the feed
 	 * sequence.
 	 */
 	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);
 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
 	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
 	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);

 	return 0;
 }

 static void lpc18xx_wdt_timer_feed(struct timer_list *t)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = from_timer(lpc18xx_wdt, t, timer);
 	struct watchdog_device *wdt_dev = &lpc18xx_wdt->wdt_dev;

 	lpc18xx_wdt_feed(wdt_dev);

 	/* Use safe value (1/2 of real timeout) */
 	mod_timer(&lpc18xx_wdt->timer, jiffies +
 		  msecs_to_jiffies((wdt_dev->timeout * MSEC_PER_SEC) / 2));
 }

 /*
  * Since LPC18xx Watchdog cannot be disabled in hardware, we must keep feeding
  * it with a timer until userspace watchdog software takes over.
  */
 static int lpc18xx_wdt_stop(struct watchdog_device *wdt_dev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);

 	lpc18xx_wdt_timer_feed(&lpc18xx_wdt->timer);

 	return 0;
 }

 static void __lpc18xx_wdt_set_timeout(struct lpc18xx_wdt_dev *lpc18xx_wdt)
 {
 	unsigned int val;

 	val = DIV_ROUND_UP(lpc18xx_wdt->wdt_dev.timeout * lpc18xx_wdt->clk_rate,
 			   LPC18XX_WDT_CLK_DIV);
 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_TC);
 }

 static int lpc18xx_wdt_set_timeout(struct watchdog_device *wdt_dev,
 				   unsigned int new_timeout)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);

 	lpc18xx_wdt->wdt_dev.timeout = new_timeout;
 	__lpc18xx_wdt_set_timeout(lpc18xx_wdt);

 	return 0;
 }

 static unsigned int lpc18xx_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
 	unsigned int val;

 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_TV);
 	return (val * LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;
 }

 static int lpc18xx_wdt_start(struct watchdog_device *wdt_dev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
 	unsigned int val;

 	if (timer_pending(&lpc18xx_wdt->timer))
 		del_timer(&lpc18xx_wdt->timer);

 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
 	val |= LPC18XX_WDT_MOD_WDEN;
 	val |= LPC18XX_WDT_MOD_WDRESET;
 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);

 	/*
 	 * Setting the WDEN bit in the WDMOD register is not sufficient to
 	 * enable the Watchdog. A valid feed sequence must be completed after
 	 * setting WDEN before the Watchdog is capable of generating a reset.
 	 */
 	lpc18xx_wdt_feed(wdt_dev);

 	return 0;
 }

 static int lpc18xx_wdt_restart(struct watchdog_device *wdt_dev,
 			       unsigned long action, void *data)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
 	unsigned long flags;
 	int val;

 	/*
 	 * Incorrect feed sequence causes immediate watchdog reset if enabled.
 	 */
 	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);

 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
 	val |= LPC18XX_WDT_MOD_WDEN;
 	val |= LPC18XX_WDT_MOD_WDRESET;
 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);

 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
 	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);

 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);

 	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);

 	return 0;
 }

 static const struct watchdog_info lpc18xx_wdt_info = {
 	.identity	= "NXP LPC18xx Watchdog",
 	.options	= WDIOF_SETTIMEOUT |
 			  WDIOF_KEEPALIVEPING |
 			  WDIOF_MAGICCLOSE,
 };

 static const struct watchdog_ops lpc18xx_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= lpc18xx_wdt_start,
 	.stop		= lpc18xx_wdt_stop,
 	.ping		= lpc18xx_wdt_feed,
 	.set_timeout	= lpc18xx_wdt_set_timeout,
 	.get_timeleft	= lpc18xx_wdt_get_timeleft,
 	.restart        = lpc18xx_wdt_restart,
 };

 static int lpc18xx_wdt_probe(struct platform_device *pdev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt;
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	int ret;

 	lpc18xx_wdt = devm_kzalloc(dev, sizeof(*lpc18xx_wdt), GFP_KERNEL);
 	if (!lpc18xx_wdt)
 		return -ENOMEM;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	lpc18xx_wdt->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(lpc18xx_wdt->base))
 		return PTR_ERR(lpc18xx_wdt->base);

 	lpc18xx_wdt->reg_clk = devm_clk_get(dev, "reg");
 	if (IS_ERR(lpc18xx_wdt->reg_clk)) {
 		dev_err(dev, "failed to get the reg clock\n");
 		return PTR_ERR(lpc18xx_wdt->reg_clk);
 	}

 	lpc18xx_wdt->wdt_clk = devm_clk_get(dev, "wdtclk");
 	if (IS_ERR(lpc18xx_wdt->wdt_clk)) {
 		dev_err(dev, "failed to get the wdt clock\n");
 		return PTR_ERR(lpc18xx_wdt->wdt_clk);
 	}

 	ret = clk_prepare_enable(lpc18xx_wdt->reg_clk);
 	if (ret) {
 		dev_err(dev, "could not prepare or enable sys clock\n");
 		return ret;
 	}

 	ret = clk_prepare_enable(lpc18xx_wdt->wdt_clk);
 	if (ret) {
 		dev_err(dev, "could not prepare or enable wdt clock\n");
 		goto disable_reg_clk;
 	}

 	/* We use the clock rate to calculate timeouts */
 	lpc18xx_wdt->clk_rate = clk_get_rate(lpc18xx_wdt->wdt_clk);
 	if (lpc18xx_wdt->clk_rate == 0) {
 		dev_err(dev, "failed to get clock rate\n");
 		ret = -EINVAL;
 		goto disable_wdt_clk;
 	}

 	lpc18xx_wdt->wdt_dev.info = &lpc18xx_wdt_info;
 	lpc18xx_wdt->wdt_dev.ops = &lpc18xx_wdt_ops;

 	lpc18xx_wdt->wdt_dev.min_timeout = DIV_ROUND_UP(LPC18XX_WDT_TC_MIN *
 				LPC18XX_WDT_CLK_DIV, lpc18xx_wdt->clk_rate);

 	lpc18xx_wdt->wdt_dev.max_timeout = (LPC18XX_WDT_TC_MAX *
 				LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;

 	lpc18xx_wdt->wdt_dev.timeout = min(lpc18xx_wdt->wdt_dev.max_timeout,
 					   LPC18XX_WDT_DEF_TIMEOUT);

 	spin_lock_init(&lpc18xx_wdt->lock);

 	lpc18xx_wdt->wdt_dev.parent = dev;
 	watchdog_set_drvdata(&lpc18xx_wdt->wdt_dev, lpc18xx_wdt);

 	ret = watchdog_init_timeout(&lpc18xx_wdt->wdt_dev, heartbeat, dev);

 	__lpc18xx_wdt_set_timeout(lpc18xx_wdt);

 	timer_setup(&lpc18xx_wdt->timer, lpc18xx_wdt_timer_feed, 0);

 	watchdog_set_nowayout(&lpc18xx_wdt->wdt_dev, nowayout);
 	watchdog_set_restart_priority(&lpc18xx_wdt->wdt_dev, 128);

 	platform_set_drvdata(pdev, lpc18xx_wdt);

 	ret = watchdog_register_device(&lpc18xx_wdt->wdt_dev);
 	if (ret)
 		goto disable_wdt_clk;

 	return 0;

 disable_wdt_clk:
 	clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
 disable_reg_clk:
 	clk_disable_unprepare(lpc18xx_wdt->reg_clk);
 	return ret;
 }

 static void lpc18xx_wdt_shutdown(struct platform_device *pdev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);

 	lpc18xx_wdt_stop(&lpc18xx_wdt->wdt_dev);
 }

 static int lpc18xx_wdt_remove(struct platform_device *pdev)
 {
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);

 	dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
 	del_timer(&lpc18xx_wdt->timer);

 	watchdog_unregister_device(&lpc18xx_wdt->wdt_dev);
 	clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
 	clk_disable_unprepare(lpc18xx_wdt->reg_clk);

 	return 0;
 }

 static const struct of_device_id lpc18xx_wdt_match[] = {
 	{ .compatible = "nxp,lpc1850-wwdt" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, lpc18xx_wdt_match);

 static struct platform_driver lpc18xx_wdt_driver = {
 	.driver = {
 		.name = "lpc18xx-wdt",
 		.of_match_table	= lpc18xx_wdt_match,
 	},
 	.probe = lpc18xx_wdt_probe,
 	.remove = lpc18xx_wdt_remove,
 	.shutdown = lpc18xx_wdt_shutdown,
 };
 module_platform_driver(lpc18xx_wdt_driver);

 MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
 MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* NXP LPC18xx Watchdog Timer (WDT)
	*
	* Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
	*
	* 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.
	*
	* Notes
	* -----
	* The Watchdog consists of a fixed divide-by-4 clock pre-scaler and a 24-bit
	* counter which decrements on every clock cycle.
	*/

	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/watchdog.h>

	/* Registers */
	#define LPC18XX_WDT_MOD 0x00
	#define LPC18XX_WDT_MOD_WDEN BIT(0)
	#define LPC18XX_WDT_MOD_WDRESET BIT(1)

	#define LPC18XX_WDT_TC 0x04
	#define LPC18XX_WDT_TC_MIN 0xff
	#define LPC18XX_WDT_TC_MAX 0xffffff

	#define LPC18XX_WDT_FEED 0x08
	#define LPC18XX_WDT_FEED_MAGIC1 0xaa
	#define LPC18XX_WDT_FEED_MAGIC2 0x55

	#define LPC18XX_WDT_TV 0x0c

	/* Clock pre-scaler */
	#define LPC18XX_WDT_CLK_DIV 4

	/* Timeout values in seconds */
	#define LPC18XX_WDT_DEF_TIMEOUT 30U

	static int heartbeat;
	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds (default="
	__MODULE_STRING(LPC18XX_WDT_DEF_TIMEOUT) ")");

	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) ")");

	struct lpc18xx_wdt_dev {
	struct watchdog_device wdt_dev;
	struct clk *reg_clk;
	struct clk *wdt_clk;
	unsigned long clk_rate;
	void __iomem *base;
	struct timer_list timer;
	spinlock_t lock;
	};

	static int lpc18xx_wdt_feed(struct watchdog_device *wdt_dev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
	unsigned long flags;

	/*
	* An abort condition will occur if an interrupt happens during the feed
	* sequence.
	*/
	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);
	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);

	return 0;
	}

	static void lpc18xx_wdt_timer_feed(struct timer_list *t)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = from_timer(lpc18xx_wdt, t, timer);
	struct watchdog_device *wdt_dev = &lpc18xx_wdt->wdt_dev;

	lpc18xx_wdt_feed(wdt_dev);

	/* Use safe value (1/2 of real timeout) */
	mod_timer(&lpc18xx_wdt->timer, jiffies +
	msecs_to_jiffies((wdt_dev->timeout * MSEC_PER_SEC) / 2));
	}

	/*
	* Since LPC18xx Watchdog cannot be disabled in hardware, we must keep feeding
	* it with a timer until userspace watchdog software takes over.
	*/
	static int lpc18xx_wdt_stop(struct watchdog_device *wdt_dev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);

	lpc18xx_wdt_timer_feed(&lpc18xx_wdt->timer);

	return 0;
	}

	static void __lpc18xx_wdt_set_timeout(struct lpc18xx_wdt_dev *lpc18xx_wdt)
	{
	unsigned int val;

	val = DIV_ROUND_UP(lpc18xx_wdt->wdt_dev.timeout * lpc18xx_wdt->clk_rate,
	LPC18XX_WDT_CLK_DIV);
	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_TC);
	}

	static int lpc18xx_wdt_set_timeout(struct watchdog_device *wdt_dev,
	unsigned int new_timeout)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);

	lpc18xx_wdt->wdt_dev.timeout = new_timeout;
	__lpc18xx_wdt_set_timeout(lpc18xx_wdt);

	return 0;
	}

	static unsigned int lpc18xx_wdt_get_timeleft(struct watchdog_device *wdt_dev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
	unsigned int val;

	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_TV);
	return (val * LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;
	}

	static int lpc18xx_wdt_start(struct watchdog_device *wdt_dev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
	unsigned int val;

	if (timer_pending(&lpc18xx_wdt->timer))
	del_timer(&lpc18xx_wdt->timer);

	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
	val \|= LPC18XX_WDT_MOD_WDEN;
	val \|= LPC18XX_WDT_MOD_WDRESET;
	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);

	/*
	* Setting the WDEN bit in the WDMOD register is not sufficient to
	* enable the Watchdog. A valid feed sequence must be completed after
	* setting WDEN before the Watchdog is capable of generating a reset.
	*/
	lpc18xx_wdt_feed(wdt_dev);

	return 0;
	}

	static int lpc18xx_wdt_restart(struct watchdog_device *wdt_dev,
	unsigned long action, void *data)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
	unsigned long flags;
	int val;

	/*
	* Incorrect feed sequence causes immediate watchdog reset if enabled.
	*/
	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);

	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
	val \|= LPC18XX_WDT_MOD_WDEN;
	val \|= LPC18XX_WDT_MOD_WDRESET;
	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);

	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);

	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);

	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);

	return 0;
	}

	static const struct watchdog_info lpc18xx_wdt_info = {
	.identity = "NXP LPC18xx Watchdog",
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};

	static const struct watchdog_ops lpc18xx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = lpc18xx_wdt_start,
	.stop = lpc18xx_wdt_stop,
	.ping = lpc18xx_wdt_feed,
	.set_timeout = lpc18xx_wdt_set_timeout,
	.get_timeleft = lpc18xx_wdt_get_timeleft,
	.restart = lpc18xx_wdt_restart,
	};

	static int lpc18xx_wdt_probe(struct platform_device *pdev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt;
	struct device *dev = &pdev->dev;
	struct resource *res;
	int ret;

	lpc18xx_wdt = devm_kzalloc(dev, sizeof(*lpc18xx_wdt), GFP_KERNEL);
	if (!lpc18xx_wdt)
	return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	lpc18xx_wdt->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(lpc18xx_wdt->base))
	return PTR_ERR(lpc18xx_wdt->base);

	lpc18xx_wdt->reg_clk = devm_clk_get(dev, "reg");
	if (IS_ERR(lpc18xx_wdt->reg_clk)) {
	dev_err(dev, "failed to get the reg clock\n");
	return PTR_ERR(lpc18xx_wdt->reg_clk);
	}

	lpc18xx_wdt->wdt_clk = devm_clk_get(dev, "wdtclk");
	if (IS_ERR(lpc18xx_wdt->wdt_clk)) {
	dev_err(dev, "failed to get the wdt clock\n");
	return PTR_ERR(lpc18xx_wdt->wdt_clk);
	}

	ret = clk_prepare_enable(lpc18xx_wdt->reg_clk);
	if (ret) {
	dev_err(dev, "could not prepare or enable sys clock\n");
	return ret;
	}

	ret = clk_prepare_enable(lpc18xx_wdt->wdt_clk);
	if (ret) {
	dev_err(dev, "could not prepare or enable wdt clock\n");
	goto disable_reg_clk;
	}

	/* We use the clock rate to calculate timeouts */
	lpc18xx_wdt->clk_rate = clk_get_rate(lpc18xx_wdt->wdt_clk);
	if (lpc18xx_wdt->clk_rate == 0) {
	dev_err(dev, "failed to get clock rate\n");
	ret = -EINVAL;
	goto disable_wdt_clk;
	}

	lpc18xx_wdt->wdt_dev.info = &lpc18xx_wdt_info;
	lpc18xx_wdt->wdt_dev.ops = &lpc18xx_wdt_ops;

	lpc18xx_wdt->wdt_dev.min_timeout = DIV_ROUND_UP(LPC18XX_WDT_TC_MIN *
	LPC18XX_WDT_CLK_DIV, lpc18xx_wdt->clk_rate);

	lpc18xx_wdt->wdt_dev.max_timeout = (LPC18XX_WDT_TC_MAX *
	LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;

	lpc18xx_wdt->wdt_dev.timeout = min(lpc18xx_wdt->wdt_dev.max_timeout,
	LPC18XX_WDT_DEF_TIMEOUT);

	spin_lock_init(&lpc18xx_wdt->lock);

	lpc18xx_wdt->wdt_dev.parent = dev;
	watchdog_set_drvdata(&lpc18xx_wdt->wdt_dev, lpc18xx_wdt);

	ret = watchdog_init_timeout(&lpc18xx_wdt->wdt_dev, heartbeat, dev);

	__lpc18xx_wdt_set_timeout(lpc18xx_wdt);

	timer_setup(&lpc18xx_wdt->timer, lpc18xx_wdt_timer_feed, 0);

	watchdog_set_nowayout(&lpc18xx_wdt->wdt_dev, nowayout);
	watchdog_set_restart_priority(&lpc18xx_wdt->wdt_dev, 128);

	platform_set_drvdata(pdev, lpc18xx_wdt);

	ret = watchdog_register_device(&lpc18xx_wdt->wdt_dev);
	if (ret)
	goto disable_wdt_clk;

	return 0;

	disable_wdt_clk:
	clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
	disable_reg_clk:
	clk_disable_unprepare(lpc18xx_wdt->reg_clk);
	return ret;
	}

	static void lpc18xx_wdt_shutdown(struct platform_device *pdev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);

	lpc18xx_wdt_stop(&lpc18xx_wdt->wdt_dev);
	}

	static int lpc18xx_wdt_remove(struct platform_device *pdev)
	{
	struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);

	dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
	del_timer(&lpc18xx_wdt->timer);

	watchdog_unregister_device(&lpc18xx_wdt->wdt_dev);
	clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
	clk_disable_unprepare(lpc18xx_wdt->reg_clk);

	return 0;
	}

	static const struct of_device_id lpc18xx_wdt_match[] = {
	{ .compatible = "nxp,lpc1850-wwdt" },
	{}
	};
	MODULE_DEVICE_TABLE(of, lpc18xx_wdt_match);

	static struct platform_driver lpc18xx_wdt_driver = {
	.driver = {
	.name = "lpc18xx-wdt",
	.of_match_table = lpc18xx_wdt_match,
	},
	.probe = lpc18xx_wdt_probe,
	.remove = lpc18xx_wdt_remove,
	.shutdown = lpc18xx_wdt_shutdown,
	};
	module_platform_driver(lpc18xx_wdt_driver);

	MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
	MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");
	MODULE_LICENSE("GPL v2");