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

 /*
  * Spreadtrum watchdog driver
  * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.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.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  */

 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>

 #define SPRD_WDT_LOAD_LOW		0x0
 #define SPRD_WDT_LOAD_HIGH		0x4
 #define SPRD_WDT_CTRL			0x8
 #define SPRD_WDT_INT_CLR		0xc
 #define SPRD_WDT_INT_RAW		0x10
 #define SPRD_WDT_INT_MSK		0x14
 #define SPRD_WDT_CNT_LOW		0x18
 #define SPRD_WDT_CNT_HIGH		0x1c
 #define SPRD_WDT_LOCK			0x20
 #define SPRD_WDT_IRQ_LOAD_LOW		0x2c
 #define SPRD_WDT_IRQ_LOAD_HIGH		0x30

 /* WDT_CTRL */
 #define SPRD_WDT_INT_EN_BIT		BIT(0)
 #define SPRD_WDT_CNT_EN_BIT		BIT(1)
 #define SPRD_WDT_NEW_VER_EN		BIT(2)
 #define SPRD_WDT_RST_EN_BIT		BIT(3)

 /* WDT_INT_CLR */
 #define SPRD_WDT_INT_CLEAR_BIT		BIT(0)
 #define SPRD_WDT_RST_CLEAR_BIT		BIT(3)

 /* WDT_INT_RAW */
 #define SPRD_WDT_INT_RAW_BIT		BIT(0)
 #define SPRD_WDT_RST_RAW_BIT		BIT(3)
 #define SPRD_WDT_LD_BUSY_BIT		BIT(4)

 /* 1s equal to 32768 counter steps */
 #define SPRD_WDT_CNT_STEP		32768

 #define SPRD_WDT_UNLOCK_KEY		0xe551
 #define SPRD_WDT_MIN_TIMEOUT		3
 #define SPRD_WDT_MAX_TIMEOUT		60

 #define SPRD_WDT_CNT_HIGH_SHIFT		16
 #define SPRD_WDT_LOW_VALUE_MASK		GENMASK(15, 0)
 #define SPRD_WDT_LOAD_TIMEOUT		1000

 struct sprd_wdt {
 	void __iomem *base;
 	struct watchdog_device wdd;
 	struct clk *enable;
 	struct clk *rtc_enable;
 	int irq;
 };

 static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd)
 {
 	return container_of(wdd, struct sprd_wdt, wdd);
 }

 static inline void sprd_wdt_lock(void __iomem *addr)
 {
 	writel_relaxed(0x0, addr + SPRD_WDT_LOCK);
 }

 static inline void sprd_wdt_unlock(void __iomem *addr)
 {
 	writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK);
 }

 static irqreturn_t sprd_wdt_isr(int irq, void *dev_id)
 {
 	struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id;

 	sprd_wdt_unlock(wdt->base);
 	writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR);
 	sprd_wdt_lock(wdt->base);
 	watchdog_notify_pretimeout(&wdt->wdd);
 	return IRQ_HANDLED;
 }

 static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt)
 {
 	u32 val;

 	val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) <<
 		SPRD_WDT_CNT_HIGH_SHIFT;
 	val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) &
 		SPRD_WDT_LOW_VALUE_MASK;

 	return val;
 }

 static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
 			       u32 pretimeout)
 {
 	u32 val, delay_cnt = 0;
 	u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
 	u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;

 	sprd_wdt_unlock(wdt->base);
 	writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
 		      SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
 	writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
 		       wdt->base + SPRD_WDT_LOAD_LOW);
 	writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
 			SPRD_WDT_LOW_VALUE_MASK,
 		       wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
 	writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
 		       wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
 	sprd_wdt_lock(wdt->base);

 	/*
 	 * Waiting the load value operation done,
 	 * it needs two or three RTC clock cycles.
 	 */
 	do {
 		val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW);
 		if (!(val & SPRD_WDT_LD_BUSY_BIT))
 			break;

 		cpu_relax();
 	} while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT);

 	if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
 		return -EBUSY;
 	return 0;
 }

 static int sprd_wdt_enable(struct sprd_wdt *wdt)
 {
 	u32 val;
 	int ret;

 	ret = clk_prepare_enable(wdt->enable);
 	if (ret)
 		return ret;
 	ret = clk_prepare_enable(wdt->rtc_enable);
 	if (ret) {
 		clk_disable_unprepare(wdt->enable);
 		return ret;
 	}

 	sprd_wdt_unlock(wdt->base);
 	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 	val |= SPRD_WDT_NEW_VER_EN;
 	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 	sprd_wdt_lock(wdt->base);
 	return 0;
 }

 static void sprd_wdt_disable(void *_data)
 {
 	struct sprd_wdt *wdt = _data;

 	sprd_wdt_unlock(wdt->base);
 	writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL);
 	sprd_wdt_lock(wdt->base);

 	clk_disable_unprepare(wdt->rtc_enable);
 	clk_disable_unprepare(wdt->enable);
 }

 static int sprd_wdt_start(struct watchdog_device *wdd)
 {
 	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 	u32 val;
 	int ret;

 	ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout);
 	if (ret)
 		return ret;

 	sprd_wdt_unlock(wdt->base);
 	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 	val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT;
 	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 	sprd_wdt_lock(wdt->base);
 	set_bit(WDOG_HW_RUNNING, &wdd->status);

 	return 0;
 }

 static int sprd_wdt_stop(struct watchdog_device *wdd)
 {
 	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 	u32 val;

 	sprd_wdt_unlock(wdt->base);
 	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 	val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT |
 		SPRD_WDT_INT_EN_BIT);
 	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 	sprd_wdt_lock(wdt->base);
 	return 0;
 }

 static int sprd_wdt_set_timeout(struct watchdog_device *wdd,
 				u32 timeout)
 {
 	struct sprd_wdt *wdt = to_sprd_wdt(wdd);

 	if (timeout == wdd->timeout)
 		return 0;

 	wdd->timeout = timeout;

 	return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout);
 }

 static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd,
 				   u32 new_pretimeout)
 {
 	struct sprd_wdt *wdt = to_sprd_wdt(wdd);

 	if (new_pretimeout < wdd->min_timeout)
 		return -EINVAL;

 	wdd->pretimeout = new_pretimeout;

 	return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout);
 }

 static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
 {
 	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 	u32 val;

 	val = sprd_wdt_get_cnt_value(wdt);
 	return val / SPRD_WDT_CNT_STEP;
 }

 static const struct watchdog_ops sprd_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = sprd_wdt_start,
 	.stop = sprd_wdt_stop,
 	.set_timeout = sprd_wdt_set_timeout,
 	.set_pretimeout = sprd_wdt_set_pretimeout,
 	.get_timeleft = sprd_wdt_get_timeleft,
 };

 static const struct watchdog_info sprd_wdt_info = {
 	.options = WDIOF_SETTIMEOUT |
 		   WDIOF_PRETIMEOUT |
 		   WDIOF_MAGICCLOSE |
 		   WDIOF_KEEPALIVEPING,
 	.identity = "Spreadtrum Watchdog Timer",
 };

 static int sprd_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct sprd_wdt *wdt;
 	int ret;

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

 	wdt->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);

 	wdt->enable = devm_clk_get(dev, "enable");
 	if (IS_ERR(wdt->enable)) {
 		dev_err(dev, "can't get the enable clock\n");
 		return PTR_ERR(wdt->enable);
 	}

 	wdt->rtc_enable = devm_clk_get(dev, "rtc_enable");
 	if (IS_ERR(wdt->rtc_enable)) {
 		dev_err(dev, "can't get the rtc enable clock\n");
 		return PTR_ERR(wdt->rtc_enable);
 	}

 	wdt->irq = platform_get_irq(pdev, 0);
 	if (wdt->irq < 0) {
 		dev_err(dev, "failed to get IRQ resource\n");
 		return wdt->irq;
 	}

 	ret = devm_request_irq(dev, wdt->irq, sprd_wdt_isr, IRQF_NO_SUSPEND,
 			       "sprd-wdt", (void *)wdt);
 	if (ret) {
 		dev_err(dev, "failed to register irq\n");
 		return ret;
 	}

 	wdt->wdd.info = &sprd_wdt_info;
 	wdt->wdd.ops = &sprd_wdt_ops;
 	wdt->wdd.parent = dev;
 	wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
 	wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
 	wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;

 	ret = sprd_wdt_enable(wdt);
 	if (ret) {
 		dev_err(dev, "failed to enable wdt\n");
 		return ret;
 	}
 	ret = devm_add_action_or_reset(dev, sprd_wdt_disable, wdt);
 	if (ret) {
 		dev_err(dev, "Failed to add wdt disable action\n");
 		return ret;
 	}

 	watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
 	watchdog_init_timeout(&wdt->wdd, 0, dev);

 	ret = devm_watchdog_register_device(dev, &wdt->wdd);
 	if (ret) {
 		sprd_wdt_disable(wdt);
 		dev_err(dev, "failed to register watchdog\n");
 		return ret;
 	}
 	platform_set_drvdata(pdev, wdt);

 	return 0;
 }

 static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 	struct sprd_wdt *wdt = dev_get_drvdata(dev);

 	if (watchdog_active(wdd))
 		sprd_wdt_stop(&wdt->wdd);
 	sprd_wdt_disable(wdt);

 	return 0;
 }

 static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 	struct sprd_wdt *wdt = dev_get_drvdata(dev);
 	int ret;

 	ret = sprd_wdt_enable(wdt);
 	if (ret)
 		return ret;

 	if (watchdog_active(wdd)) {
 		ret = sprd_wdt_start(&wdt->wdd);
 		if (ret) {
 			sprd_wdt_disable(wdt);
 			return ret;
 		}
 	}

 	return 0;
 }

 static const struct dev_pm_ops sprd_wdt_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend,
 				sprd_wdt_pm_resume)
 };

 static const struct of_device_id sprd_wdt_match_table[] = {
 	{ .compatible = "sprd,sp9860-wdt", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, sprd_wdt_match_table);

 static struct platform_driver sprd_watchdog_driver = {
 	.probe	= sprd_wdt_probe,
 	.driver	= {
 		.name = "sprd-wdt",
 		.of_match_table = sprd_wdt_match_table,
 		.pm = &sprd_wdt_pm_ops,
 	},
 };
 module_platform_driver(sprd_watchdog_driver);

 MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>");
 MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Spreadtrum watchdog driver
	* Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.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.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*/

	#include <linux/bitops.h>
	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/platform_device.h>
	#include <linux/watchdog.h>

	#define SPRD_WDT_LOAD_LOW 0x0
	#define SPRD_WDT_LOAD_HIGH 0x4
	#define SPRD_WDT_CTRL 0x8
	#define SPRD_WDT_INT_CLR 0xc
	#define SPRD_WDT_INT_RAW 0x10
	#define SPRD_WDT_INT_MSK 0x14
	#define SPRD_WDT_CNT_LOW 0x18
	#define SPRD_WDT_CNT_HIGH 0x1c
	#define SPRD_WDT_LOCK 0x20
	#define SPRD_WDT_IRQ_LOAD_LOW 0x2c
	#define SPRD_WDT_IRQ_LOAD_HIGH 0x30

	/* WDT_CTRL */
	#define SPRD_WDT_INT_EN_BIT BIT(0)
	#define SPRD_WDT_CNT_EN_BIT BIT(1)
	#define SPRD_WDT_NEW_VER_EN BIT(2)
	#define SPRD_WDT_RST_EN_BIT BIT(3)

	/* WDT_INT_CLR */
	#define SPRD_WDT_INT_CLEAR_BIT BIT(0)
	#define SPRD_WDT_RST_CLEAR_BIT BIT(3)

	/* WDT_INT_RAW */
	#define SPRD_WDT_INT_RAW_BIT BIT(0)
	#define SPRD_WDT_RST_RAW_BIT BIT(3)
	#define SPRD_WDT_LD_BUSY_BIT BIT(4)

	/* 1s equal to 32768 counter steps */
	#define SPRD_WDT_CNT_STEP 32768

	#define SPRD_WDT_UNLOCK_KEY 0xe551
	#define SPRD_WDT_MIN_TIMEOUT 3
	#define SPRD_WDT_MAX_TIMEOUT 60

	#define SPRD_WDT_CNT_HIGH_SHIFT 16
	#define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0)
	#define SPRD_WDT_LOAD_TIMEOUT 1000

	struct sprd_wdt {
	void __iomem *base;
	struct watchdog_device wdd;
	struct clk *enable;
	struct clk *rtc_enable;
	int irq;
	};

	static inline struct sprd_wdt to_sprd_wdt(struct watchdog_device wdd)
	{
	return container_of(wdd, struct sprd_wdt, wdd);
	}

	static inline void sprd_wdt_lock(void __iomem *addr)
	{
	writel_relaxed(0x0, addr + SPRD_WDT_LOCK);
	}

	static inline void sprd_wdt_unlock(void __iomem *addr)
	{
	writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK);
	}

	static irqreturn_t sprd_wdt_isr(int irq, void *dev_id)
	{
	struct sprd_wdt wdt = (struct sprd_wdt )dev_id;

	sprd_wdt_unlock(wdt->base);
	writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR);
	sprd_wdt_lock(wdt->base);
	watchdog_notify_pretimeout(&wdt->wdd);
	return IRQ_HANDLED;
	}

	static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt)
	{
	u32 val;

	val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) <<
	SPRD_WDT_CNT_HIGH_SHIFT;
	val \|= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) &
	SPRD_WDT_LOW_VALUE_MASK;

	return val;
	}

	static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
	u32 pretimeout)
	{
	u32 val, delay_cnt = 0;
	u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
	u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;

	sprd_wdt_unlock(wdt->base);
	writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
	SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
	writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
	wdt->base + SPRD_WDT_LOAD_LOW);
	writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
	SPRD_WDT_LOW_VALUE_MASK,
	wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
	writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
	wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
	sprd_wdt_lock(wdt->base);

	/*
	* Waiting the load value operation done,
	* it needs two or three RTC clock cycles.
	*/
	do {
	val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW);
	if (!(val & SPRD_WDT_LD_BUSY_BIT))
	break;

	cpu_relax();
	} while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT);

	if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
	return -EBUSY;
	return 0;
	}

	static int sprd_wdt_enable(struct sprd_wdt *wdt)
	{
	u32 val;
	int ret;

	ret = clk_prepare_enable(wdt->enable);
	if (ret)
	return ret;
	ret = clk_prepare_enable(wdt->rtc_enable);
	if (ret) {
	clk_disable_unprepare(wdt->enable);
	return ret;
	}

	sprd_wdt_unlock(wdt->base);
	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
	val \|= SPRD_WDT_NEW_VER_EN;
	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
	sprd_wdt_lock(wdt->base);
	return 0;
	}

	static void sprd_wdt_disable(void *_data)
	{
	struct sprd_wdt *wdt = _data;

	sprd_wdt_unlock(wdt->base);
	writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL);
	sprd_wdt_lock(wdt->base);

	clk_disable_unprepare(wdt->rtc_enable);
	clk_disable_unprepare(wdt->enable);
	}

	static int sprd_wdt_start(struct watchdog_device *wdd)
	{
	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
	u32 val;
	int ret;

	ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout);
	if (ret)
	return ret;

	sprd_wdt_unlock(wdt->base);
	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
	val \|= SPRD_WDT_CNT_EN_BIT \| SPRD_WDT_INT_EN_BIT \| SPRD_WDT_RST_EN_BIT;
	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
	sprd_wdt_lock(wdt->base);
	set_bit(WDOG_HW_RUNNING, &wdd->status);

	return 0;
	}

	static int sprd_wdt_stop(struct watchdog_device *wdd)
	{
	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
	u32 val;

	sprd_wdt_unlock(wdt->base);
	val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
	val &= ~(SPRD_WDT_CNT_EN_BIT \| SPRD_WDT_RST_EN_BIT \|
	SPRD_WDT_INT_EN_BIT);
	writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
	sprd_wdt_lock(wdt->base);
	return 0;
	}

	static int sprd_wdt_set_timeout(struct watchdog_device *wdd,
	u32 timeout)
	{
	struct sprd_wdt *wdt = to_sprd_wdt(wdd);

	if (timeout == wdd->timeout)
	return 0;

	wdd->timeout = timeout;

	return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout);
	}

	static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd,
	u32 new_pretimeout)
	{
	struct sprd_wdt *wdt = to_sprd_wdt(wdd);

	if (new_pretimeout < wdd->min_timeout)
	return -EINVAL;

	wdd->pretimeout = new_pretimeout;

	return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout);
	}

	static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
	{
	struct sprd_wdt *wdt = to_sprd_wdt(wdd);
	u32 val;

	val = sprd_wdt_get_cnt_value(wdt);
	return val / SPRD_WDT_CNT_STEP;
	}

	static const struct watchdog_ops sprd_wdt_ops = {
	.owner = THIS_MODULE,
	.start = sprd_wdt_start,
	.stop = sprd_wdt_stop,
	.set_timeout = sprd_wdt_set_timeout,
	.set_pretimeout = sprd_wdt_set_pretimeout,
	.get_timeleft = sprd_wdt_get_timeleft,
	};

	static const struct watchdog_info sprd_wdt_info = {
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_PRETIMEOUT \|
	WDIOF_MAGICCLOSE \|
	WDIOF_KEEPALIVEPING,
	.identity = "Spreadtrum Watchdog Timer",
	};

	static int sprd_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct sprd_wdt *wdt;
	int ret;

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

	wdt->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(wdt->base))
	return PTR_ERR(wdt->base);

	wdt->enable = devm_clk_get(dev, "enable");
	if (IS_ERR(wdt->enable)) {
	dev_err(dev, "can't get the enable clock\n");
	return PTR_ERR(wdt->enable);
	}

	wdt->rtc_enable = devm_clk_get(dev, "rtc_enable");
	if (IS_ERR(wdt->rtc_enable)) {
	dev_err(dev, "can't get the rtc enable clock\n");
	return PTR_ERR(wdt->rtc_enable);
	}

	wdt->irq = platform_get_irq(pdev, 0);
	if (wdt->irq < 0) {
	dev_err(dev, "failed to get IRQ resource\n");
	return wdt->irq;
	}

	ret = devm_request_irq(dev, wdt->irq, sprd_wdt_isr, IRQF_NO_SUSPEND,
	"sprd-wdt", (void *)wdt);
	if (ret) {
	dev_err(dev, "failed to register irq\n");
	return ret;
	}

	wdt->wdd.info = &sprd_wdt_info;
	wdt->wdd.ops = &sprd_wdt_ops;
	wdt->wdd.parent = dev;
	wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
	wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
	wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;

	ret = sprd_wdt_enable(wdt);
	if (ret) {
	dev_err(dev, "failed to enable wdt\n");
	return ret;
	}
	ret = devm_add_action_or_reset(dev, sprd_wdt_disable, wdt);
	if (ret) {
	dev_err(dev, "Failed to add wdt disable action\n");
	return ret;
	}

	watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
	watchdog_init_timeout(&wdt->wdd, 0, dev);

	ret = devm_watchdog_register_device(dev, &wdt->wdd);
	if (ret) {
	sprd_wdt_disable(wdt);
	dev_err(dev, "failed to register watchdog\n");
	return ret;
	}
	platform_set_drvdata(pdev, wdt);

	return 0;
	}

	static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
	{
	struct watchdog_device *wdd = dev_get_drvdata(dev);
	struct sprd_wdt *wdt = dev_get_drvdata(dev);

	if (watchdog_active(wdd))
	sprd_wdt_stop(&wdt->wdd);
	sprd_wdt_disable(wdt);

	return 0;
	}

	static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
	{
	struct watchdog_device *wdd = dev_get_drvdata(dev);
	struct sprd_wdt *wdt = dev_get_drvdata(dev);
	int ret;

	ret = sprd_wdt_enable(wdt);
	if (ret)
	return ret;

	if (watchdog_active(wdd)) {
	ret = sprd_wdt_start(&wdt->wdd);
	if (ret) {
	sprd_wdt_disable(wdt);
	return ret;
	}
	}

	return 0;
	}

	static const struct dev_pm_ops sprd_wdt_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend,
	sprd_wdt_pm_resume)
	};

	static const struct of_device_id sprd_wdt_match_table[] = {
	{ .compatible = "sprd,sp9860-wdt", },
	{},
	};
	MODULE_DEVICE_TABLE(of, sprd_wdt_match_table);

	static struct platform_driver sprd_watchdog_driver = {
	.probe = sprd_wdt_probe,
	.driver = {
	.name = "sprd-wdt",
	.of_match_table = sprd_wdt_match_table,
	.pm = &sprd_wdt_pm_ops,
	},
	};
	module_platform_driver(sprd_watchdog_driver);

	MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>");
	MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
	MODULE_LICENSE("GPL v2");