drivers/watchdog/imx7ulp_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright 2019 NXP.
  */

 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/reboot.h>
 #include <linux/watchdog.h>

 #define WDOG_CS			0x0
 #define WDOG_CS_FLG		BIT(14)
 #define WDOG_CS_CMD32EN		BIT(13)
 #define WDOG_CS_PRES		BIT(12)
 #define WDOG_CS_ULK		BIT(11)
 #define WDOG_CS_RCS		BIT(10)
 #define LPO_CLK			0x1
 #define LPO_CLK_SHIFT		8
 #define WDOG_CS_CLK		(LPO_CLK << LPO_CLK_SHIFT)
 #define WDOG_CS_EN		BIT(7)
 #define WDOG_CS_UPDATE		BIT(5)
 #define WDOG_CS_WAIT		BIT(1)
 #define WDOG_CS_STOP		BIT(0)

 #define WDOG_CNT	0x4
 #define WDOG_TOVAL	0x8

 #define REFRESH_SEQ0	0xA602
 #define REFRESH_SEQ1	0xB480
 #define REFRESH		((REFRESH_SEQ1 << 16) | REFRESH_SEQ0)

 #define UNLOCK_SEQ0	0xC520
 #define UNLOCK_SEQ1	0xD928
 #define UNLOCK		((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0)

 #define DEFAULT_TIMEOUT	60
 #define MAX_TIMEOUT	128
 #define WDOG_CLOCK_RATE	1000
 #define WDOG_ULK_WAIT_TIMEOUT	1000
 #define WDOG_RCS_WAIT_TIMEOUT	10000
 #define WDOG_RCS_POST_WAIT 3000

 #define RETRY_MAX 5

 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0000);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 struct imx_wdt_hw_feature {
 	bool prescaler_enable;
 	u32 wdog_clock_rate;
 };

 struct imx7ulp_wdt_device {
 	struct watchdog_device wdd;
 	void __iomem *base;
 	struct clk *clk;
 	bool post_rcs_wait;
 	const struct imx_wdt_hw_feature *hw;
 };

 static int imx7ulp_wdt_wait_ulk(void __iomem *base)
 {
 	u32 val = readl(base + WDOG_CS);

 	if (!(val & WDOG_CS_ULK) &&
 	    readl_poll_timeout_atomic(base + WDOG_CS, val,
 				      val & WDOG_CS_ULK, 0,
 				      WDOG_ULK_WAIT_TIMEOUT))
 		return -ETIMEDOUT;

 	return 0;
 }

 static int imx7ulp_wdt_wait_rcs(struct imx7ulp_wdt_device *wdt)
 {
 	int ret = 0;
 	u32 val = readl(wdt->base + WDOG_CS);
 	u64 timeout = (val & WDOG_CS_PRES) ?
 		WDOG_RCS_WAIT_TIMEOUT * 256 : WDOG_RCS_WAIT_TIMEOUT;
 	unsigned long wait_min = (val & WDOG_CS_PRES) ?
 		WDOG_RCS_POST_WAIT * 256 : WDOG_RCS_POST_WAIT;

 	if (!(val & WDOG_CS_RCS) &&
 	    readl_poll_timeout(wdt->base + WDOG_CS, val, val & WDOG_CS_RCS, 100,
 			       timeout))
 		ret = -ETIMEDOUT;

 	/* Wait 2.5 clocks after RCS done */
 	if (wdt->post_rcs_wait)
 		usleep_range(wait_min, wait_min + 2000);

 	return ret;
 }

 static int _imx7ulp_wdt_enable(struct imx7ulp_wdt_device *wdt, bool enable)
 {
 	u32 val = readl(wdt->base + WDOG_CS);
 	int ret;

 	local_irq_disable();
 	writel(UNLOCK, wdt->base + WDOG_CNT);
 	ret = imx7ulp_wdt_wait_ulk(wdt->base);
 	if (ret)
 		goto enable_out;
 	if (enable)
 		writel(val | WDOG_CS_EN, wdt->base + WDOG_CS);
 	else
 		writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);

 	local_irq_enable();
 	ret = imx7ulp_wdt_wait_rcs(wdt);

 	return ret;

 enable_out:
 	local_irq_enable();
 	return ret;
 }

 static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
 {
 	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 	int ret;
 	u32 val;
 	u32 loop = RETRY_MAX;

 	do {
 		ret = _imx7ulp_wdt_enable(wdt, enable);
 		val = readl(wdt->base + WDOG_CS);
 	} while (--loop > 0 && ((!!(val & WDOG_CS_EN)) != enable || ret));

 	if (loop == 0)
 		return -EBUSY;

 	return ret;
 }

 static int imx7ulp_wdt_ping(struct watchdog_device *wdog)
 {
 	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);

 	writel(REFRESH, wdt->base + WDOG_CNT);

 	return 0;
 }

 static int imx7ulp_wdt_start(struct watchdog_device *wdog)
 {
 	return imx7ulp_wdt_enable(wdog, true);
 }

 static int imx7ulp_wdt_stop(struct watchdog_device *wdog)
 {
 	return imx7ulp_wdt_enable(wdog, false);
 }

 static int _imx7ulp_wdt_set_timeout(struct imx7ulp_wdt_device *wdt,
 				   unsigned int toval)
 {
 	int ret;

 	local_irq_disable();
 	writel(UNLOCK, wdt->base + WDOG_CNT);
 	ret = imx7ulp_wdt_wait_ulk(wdt->base);
 	if (ret)
 		goto timeout_out;
 	writel(toval, wdt->base + WDOG_TOVAL);
 	local_irq_enable();
 	ret = imx7ulp_wdt_wait_rcs(wdt);
 	return ret;

 timeout_out:
 	local_irq_enable();
 	return ret;
 }

 static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
 				   unsigned int timeout)
 {
 	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 	u32 toval = wdt->hw->wdog_clock_rate * timeout;
 	u32 val;
 	int ret;
 	u32 loop = RETRY_MAX;

 	do {
 		ret = _imx7ulp_wdt_set_timeout(wdt, toval);
 		val = readl(wdt->base + WDOG_TOVAL);
 	} while (--loop > 0 && (val != toval || ret));

 	if (loop == 0)
 		return -EBUSY;

 	wdog->timeout = timeout;
 	return ret;
 }

 static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
 			       unsigned long action, void *data)
 {
 	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 	int ret;

 	ret = imx7ulp_wdt_enable(wdog, true);
 	if (ret)
 		return ret;

 	ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
 	if (ret)
 		return ret;

 	/* wait for wdog to fire */
 	while (true)
 		;

 	return NOTIFY_DONE;
 }

 static const struct watchdog_ops imx7ulp_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx7ulp_wdt_start,
 	.stop  = imx7ulp_wdt_stop,
 	.ping  = imx7ulp_wdt_ping,
 	.set_timeout = imx7ulp_wdt_set_timeout,
 	.restart = imx7ulp_wdt_restart,
 };

 static const struct watchdog_info imx7ulp_wdt_info = {
 	.identity = "i.MX7ULP watchdog timer",
 	.options  = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 		    WDIOF_MAGICCLOSE,
 };

 static int _imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout, unsigned int cs)
 {
 	u32 val;
 	int ret;

 	local_irq_disable();

 	val = readl(wdt->base + WDOG_CS);
 	if (val & WDOG_CS_CMD32EN) {
 		writel(UNLOCK, wdt->base + WDOG_CNT);
 	} else {
 		mb();
 		/* unlock the wdog for reconfiguration */
 		writel_relaxed(UNLOCK_SEQ0, wdt->base + WDOG_CNT);
 		writel_relaxed(UNLOCK_SEQ1, wdt->base + WDOG_CNT);
 		mb();
 	}

 	ret = imx7ulp_wdt_wait_ulk(wdt->base);
 	if (ret)
 		goto init_out;

 	/* set an initial timeout value in TOVAL */
 	writel(timeout, wdt->base + WDOG_TOVAL);
 	writel(cs, wdt->base + WDOG_CS);
 	local_irq_enable();
 	ret = imx7ulp_wdt_wait_rcs(wdt);

 	return ret;

 init_out:
 	local_irq_enable();
 	return ret;
 }

 static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout)
 {
 	/* enable 32bit command sequence and reconfigure */
 	u32 val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE |
 		  WDOG_CS_WAIT | WDOG_CS_STOP;
 	u32 cs, toval;
 	int ret;
 	u32 loop = RETRY_MAX;

 	if (wdt->hw->prescaler_enable)
 		val |= WDOG_CS_PRES;

 	do {
 		ret = _imx7ulp_wdt_init(wdt, timeout, val);
 		toval = readl(wdt->base + WDOG_TOVAL);
 		cs = readl(wdt->base + WDOG_CS);
 		cs &= ~(WDOG_CS_FLG | WDOG_CS_ULK | WDOG_CS_RCS);
 	} while (--loop > 0 && (cs != val || toval != timeout || ret));

 	if (loop == 0)
 		return -EBUSY;

 	return ret;
 }

 static void imx7ulp_wdt_action(void *data)
 {
 	clk_disable_unprepare(data);
 }

 static int imx7ulp_wdt_probe(struct platform_device *pdev)
 {
 	struct imx7ulp_wdt_device *imx7ulp_wdt;
 	struct device *dev = &pdev->dev;
 	struct watchdog_device *wdog;
 	int ret;

 	imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL);
 	if (!imx7ulp_wdt)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, imx7ulp_wdt);

 	imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(imx7ulp_wdt->base))
 		return PTR_ERR(imx7ulp_wdt->base);

 	imx7ulp_wdt->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(imx7ulp_wdt->clk)) {
 		dev_err(dev, "Failed to get watchdog clock\n");
 		return PTR_ERR(imx7ulp_wdt->clk);
 	}

 	imx7ulp_wdt->post_rcs_wait = true;
 	if (of_device_is_compatible(dev->of_node,
 				    "fsl,imx8ulp-wdt")) {
 		dev_info(dev, "imx8ulp wdt probe\n");
 		imx7ulp_wdt->post_rcs_wait = false;
 	} else {
 		dev_info(dev, "imx7ulp wdt probe\n");
 	}

 	ret = clk_prepare_enable(imx7ulp_wdt->clk);
 	if (ret)
 		return ret;

 	ret = devm_add_action_or_reset(dev, imx7ulp_wdt_action, imx7ulp_wdt->clk);
 	if (ret)
 		return ret;

 	wdog = &imx7ulp_wdt->wdd;
 	wdog->info = &imx7ulp_wdt_info;
 	wdog->ops = &imx7ulp_wdt_ops;
 	wdog->min_timeout = 1;
 	wdog->max_timeout = MAX_TIMEOUT;
 	wdog->parent = dev;
 	wdog->timeout = DEFAULT_TIMEOUT;

 	watchdog_init_timeout(wdog, 0, dev);
 	watchdog_stop_on_reboot(wdog);
 	watchdog_stop_on_unregister(wdog);
 	watchdog_set_drvdata(wdog, imx7ulp_wdt);

 	imx7ulp_wdt->hw = of_device_get_match_data(dev);
 	ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * imx7ulp_wdt->hw->wdog_clock_rate);
 	if (ret)
 		return ret;

 	return devm_watchdog_register_device(dev, wdog);
 }

 static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev)
 {
 	struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);

 	if (watchdog_active(&imx7ulp_wdt->wdd))
 		imx7ulp_wdt_stop(&imx7ulp_wdt->wdd);

 	clk_disable_unprepare(imx7ulp_wdt->clk);

 	return 0;
 }

 static int __maybe_unused imx7ulp_wdt_resume_noirq(struct device *dev)
 {
 	struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
 	u32 timeout = imx7ulp_wdt->wdd.timeout * imx7ulp_wdt->hw->wdog_clock_rate;
 	int ret;

 	ret = clk_prepare_enable(imx7ulp_wdt->clk);
 	if (ret)
 		return ret;

 	if (watchdog_active(&imx7ulp_wdt->wdd)) {
 		imx7ulp_wdt_init(imx7ulp_wdt, timeout);
 		imx7ulp_wdt_start(&imx7ulp_wdt->wdd);
 		imx7ulp_wdt_ping(&imx7ulp_wdt->wdd);
 	}

 	return 0;
 }

 static const struct dev_pm_ops imx7ulp_wdt_pm_ops = {
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx7ulp_wdt_suspend_noirq,
 				      imx7ulp_wdt_resume_noirq)
 };

 static const struct imx_wdt_hw_feature imx7ulp_wdt_hw = {
 	.prescaler_enable = false,
 	.wdog_clock_rate = 1000,
 };

 static const struct imx_wdt_hw_feature imx93_wdt_hw = {
 	.prescaler_enable = true,
 	.wdog_clock_rate = 125,
 };

 static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
 	{ .compatible = "fsl,imx8ulp-wdt", .data = &imx7ulp_wdt_hw, },
 	{ .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, },
 	{ .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);

 static struct platform_driver imx7ulp_wdt_driver = {
 	.probe		= imx7ulp_wdt_probe,
 	.driver		= {
 		.name	= "imx7ulp-wdt",
 		.pm	= &imx7ulp_wdt_pm_ops,
 		.of_match_table = imx7ulp_wdt_dt_ids,
 	},
 };
 module_platform_driver(imx7ulp_wdt_driver);

 MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
 MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright 2019 NXP.
	*/

	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/iopoll.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/reboot.h>
	#include <linux/watchdog.h>

	#define WDOG_CS 0x0
	#define WDOG_CS_FLG BIT(14)
	#define WDOG_CS_CMD32EN BIT(13)
	#define WDOG_CS_PRES BIT(12)
	#define WDOG_CS_ULK BIT(11)
	#define WDOG_CS_RCS BIT(10)
	#define LPO_CLK 0x1
	#define LPO_CLK_SHIFT 8
	#define WDOG_CS_CLK (LPO_CLK << LPO_CLK_SHIFT)
	#define WDOG_CS_EN BIT(7)
	#define WDOG_CS_UPDATE BIT(5)
	#define WDOG_CS_WAIT BIT(1)
	#define WDOG_CS_STOP BIT(0)

	#define WDOG_CNT 0x4
	#define WDOG_TOVAL 0x8

	#define REFRESH_SEQ0 0xA602
	#define REFRESH_SEQ1 0xB480
	#define REFRESH ((REFRESH_SEQ1 << 16) \| REFRESH_SEQ0)

	#define UNLOCK_SEQ0 0xC520
	#define UNLOCK_SEQ1 0xD928
	#define UNLOCK ((UNLOCK_SEQ1 << 16) \| UNLOCK_SEQ0)

	#define DEFAULT_TIMEOUT 60
	#define MAX_TIMEOUT 128
	#define WDOG_CLOCK_RATE 1000
	#define WDOG_ULK_WAIT_TIMEOUT 1000
	#define WDOG_RCS_WAIT_TIMEOUT 10000
	#define WDOG_RCS_POST_WAIT 3000

	#define RETRY_MAX 5

	static bool nowayout = WATCHDOG_NOWAYOUT;
	module_param(nowayout, bool, 0000);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	struct imx_wdt_hw_feature {
	bool prescaler_enable;
	u32 wdog_clock_rate;
	};

	struct imx7ulp_wdt_device {
	struct watchdog_device wdd;
	void __iomem *base;
	struct clk *clk;
	bool post_rcs_wait;
	const struct imx_wdt_hw_feature *hw;
	};

	static int imx7ulp_wdt_wait_ulk(void __iomem *base)
	{
	u32 val = readl(base + WDOG_CS);

	if (!(val & WDOG_CS_ULK) &&
	readl_poll_timeout_atomic(base + WDOG_CS, val,
	val & WDOG_CS_ULK, 0,
	WDOG_ULK_WAIT_TIMEOUT))
	return -ETIMEDOUT;

	return 0;
	}

	static int imx7ulp_wdt_wait_rcs(struct imx7ulp_wdt_device *wdt)
	{
	int ret = 0;
	u32 val = readl(wdt->base + WDOG_CS);
	u64 timeout = (val & WDOG_CS_PRES) ?
	WDOG_RCS_WAIT_TIMEOUT * 256 : WDOG_RCS_WAIT_TIMEOUT;
	unsigned long wait_min = (val & WDOG_CS_PRES) ?
	WDOG_RCS_POST_WAIT * 256 : WDOG_RCS_POST_WAIT;

	if (!(val & WDOG_CS_RCS) &&
	readl_poll_timeout(wdt->base + WDOG_CS, val, val & WDOG_CS_RCS, 100,
	timeout))
	ret = -ETIMEDOUT;

	/* Wait 2.5 clocks after RCS done */
	if (wdt->post_rcs_wait)
	usleep_range(wait_min, wait_min + 2000);

	return ret;
	}

	static int _imx7ulp_wdt_enable(struct imx7ulp_wdt_device *wdt, bool enable)
	{
	u32 val = readl(wdt->base + WDOG_CS);
	int ret;

	local_irq_disable();
	writel(UNLOCK, wdt->base + WDOG_CNT);
	ret = imx7ulp_wdt_wait_ulk(wdt->base);
	if (ret)
	goto enable_out;
	if (enable)
	writel(val \| WDOG_CS_EN, wdt->base + WDOG_CS);
	else
	writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);

	local_irq_enable();
	ret = imx7ulp_wdt_wait_rcs(wdt);

	return ret;

	enable_out:
	local_irq_enable();
	return ret;
	}

	static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
	{
	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
	int ret;
	u32 val;
	u32 loop = RETRY_MAX;

	do {
	ret = _imx7ulp_wdt_enable(wdt, enable);
	val = readl(wdt->base + WDOG_CS);
	} while (--loop > 0 && ((!!(val & WDOG_CS_EN)) != enable \|\| ret));

	if (loop == 0)
	return -EBUSY;

	return ret;
	}

	static int imx7ulp_wdt_ping(struct watchdog_device *wdog)
	{
	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);

	writel(REFRESH, wdt->base + WDOG_CNT);

	return 0;
	}

	static int imx7ulp_wdt_start(struct watchdog_device *wdog)
	{
	return imx7ulp_wdt_enable(wdog, true);
	}

	static int imx7ulp_wdt_stop(struct watchdog_device *wdog)
	{
	return imx7ulp_wdt_enable(wdog, false);
	}

	static int _imx7ulp_wdt_set_timeout(struct imx7ulp_wdt_device *wdt,
	unsigned int toval)
	{
	int ret;

	local_irq_disable();
	writel(UNLOCK, wdt->base + WDOG_CNT);
	ret = imx7ulp_wdt_wait_ulk(wdt->base);
	if (ret)
	goto timeout_out;
	writel(toval, wdt->base + WDOG_TOVAL);
	local_irq_enable();
	ret = imx7ulp_wdt_wait_rcs(wdt);
	return ret;

	timeout_out:
	local_irq_enable();
	return ret;
	}

	static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
	unsigned int timeout)
	{
	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
	u32 toval = wdt->hw->wdog_clock_rate * timeout;
	u32 val;
	int ret;
	u32 loop = RETRY_MAX;

	do {
	ret = _imx7ulp_wdt_set_timeout(wdt, toval);
	val = readl(wdt->base + WDOG_TOVAL);
	} while (--loop > 0 && (val != toval \|\| ret));

	if (loop == 0)
	return -EBUSY;

	wdog->timeout = timeout;
	return ret;
	}

	static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
	unsigned long action, void *data)
	{
	struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
	int ret;

	ret = imx7ulp_wdt_enable(wdog, true);
	if (ret)
	return ret;

	ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
	if (ret)
	return ret;

	/* wait for wdog to fire */
	while (true)
	;

	return NOTIFY_DONE;
	}

	static const struct watchdog_ops imx7ulp_wdt_ops = {
	.owner = THIS_MODULE,
	.start = imx7ulp_wdt_start,
	.stop = imx7ulp_wdt_stop,
	.ping = imx7ulp_wdt_ping,
	.set_timeout = imx7ulp_wdt_set_timeout,
	.restart = imx7ulp_wdt_restart,
	};

	static const struct watchdog_info imx7ulp_wdt_info = {
	.identity = "i.MX7ULP watchdog timer",
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};

	static int _imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout, unsigned int cs)
	{
	u32 val;
	int ret;

	local_irq_disable();

	val = readl(wdt->base + WDOG_CS);
	if (val & WDOG_CS_CMD32EN) {
	writel(UNLOCK, wdt->base + WDOG_CNT);
	} else {
	mb();
	/* unlock the wdog for reconfiguration */
	writel_relaxed(UNLOCK_SEQ0, wdt->base + WDOG_CNT);
	writel_relaxed(UNLOCK_SEQ1, wdt->base + WDOG_CNT);
	mb();
	}

	ret = imx7ulp_wdt_wait_ulk(wdt->base);
	if (ret)
	goto init_out;

	/* set an initial timeout value in TOVAL */
	writel(timeout, wdt->base + WDOG_TOVAL);
	writel(cs, wdt->base + WDOG_CS);
	local_irq_enable();
	ret = imx7ulp_wdt_wait_rcs(wdt);

	return ret;

	init_out:
	local_irq_enable();
	return ret;
	}

	static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout)
	{
	/* enable 32bit command sequence and reconfigure */
	u32 val = WDOG_CS_CMD32EN \| WDOG_CS_CLK \| WDOG_CS_UPDATE \|
	WDOG_CS_WAIT \| WDOG_CS_STOP;
	u32 cs, toval;
	int ret;
	u32 loop = RETRY_MAX;

	if (wdt->hw->prescaler_enable)
	val \|= WDOG_CS_PRES;

	do {
	ret = _imx7ulp_wdt_init(wdt, timeout, val);
	toval = readl(wdt->base + WDOG_TOVAL);
	cs = readl(wdt->base + WDOG_CS);
	cs &= ~(WDOG_CS_FLG \| WDOG_CS_ULK \| WDOG_CS_RCS);
	} while (--loop > 0 && (cs != val \|\| toval != timeout \|\| ret));

	if (loop == 0)
	return -EBUSY;

	return ret;
	}

	static void imx7ulp_wdt_action(void *data)
	{
	clk_disable_unprepare(data);
	}

	static int imx7ulp_wdt_probe(struct platform_device *pdev)
	{
	struct imx7ulp_wdt_device *imx7ulp_wdt;
	struct device *dev = &pdev->dev;
	struct watchdog_device *wdog;
	int ret;

	imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL);
	if (!imx7ulp_wdt)
	return -ENOMEM;

	platform_set_drvdata(pdev, imx7ulp_wdt);

	imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(imx7ulp_wdt->base))
	return PTR_ERR(imx7ulp_wdt->base);

	imx7ulp_wdt->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(imx7ulp_wdt->clk)) {
	dev_err(dev, "Failed to get watchdog clock\n");
	return PTR_ERR(imx7ulp_wdt->clk);
	}

	imx7ulp_wdt->post_rcs_wait = true;
	if (of_device_is_compatible(dev->of_node,
	"fsl,imx8ulp-wdt")) {
	dev_info(dev, "imx8ulp wdt probe\n");
	imx7ulp_wdt->post_rcs_wait = false;
	} else {
	dev_info(dev, "imx7ulp wdt probe\n");
	}

	ret = clk_prepare_enable(imx7ulp_wdt->clk);
	if (ret)
	return ret;

	ret = devm_add_action_or_reset(dev, imx7ulp_wdt_action, imx7ulp_wdt->clk);
	if (ret)
	return ret;

	wdog = &imx7ulp_wdt->wdd;
	wdog->info = &imx7ulp_wdt_info;
	wdog->ops = &imx7ulp_wdt_ops;
	wdog->min_timeout = 1;
	wdog->max_timeout = MAX_TIMEOUT;
	wdog->parent = dev;
	wdog->timeout = DEFAULT_TIMEOUT;

	watchdog_init_timeout(wdog, 0, dev);
	watchdog_stop_on_reboot(wdog);
	watchdog_stop_on_unregister(wdog);
	watchdog_set_drvdata(wdog, imx7ulp_wdt);

	imx7ulp_wdt->hw = of_device_get_match_data(dev);
	ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * imx7ulp_wdt->hw->wdog_clock_rate);
	if (ret)
	return ret;

	return devm_watchdog_register_device(dev, wdog);
	}

	static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev)
	{
	struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);

	if (watchdog_active(&imx7ulp_wdt->wdd))
	imx7ulp_wdt_stop(&imx7ulp_wdt->wdd);

	clk_disable_unprepare(imx7ulp_wdt->clk);

	return 0;
	}

	static int __maybe_unused imx7ulp_wdt_resume_noirq(struct device *dev)
	{
	struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
	u32 timeout = imx7ulp_wdt->wdd.timeout * imx7ulp_wdt->hw->wdog_clock_rate;
	int ret;

	ret = clk_prepare_enable(imx7ulp_wdt->clk);
	if (ret)
	return ret;

	if (watchdog_active(&imx7ulp_wdt->wdd)) {
	imx7ulp_wdt_init(imx7ulp_wdt, timeout);
	imx7ulp_wdt_start(&imx7ulp_wdt->wdd);
	imx7ulp_wdt_ping(&imx7ulp_wdt->wdd);
	}

	return 0;
	}

	static const struct dev_pm_ops imx7ulp_wdt_pm_ops = {
	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx7ulp_wdt_suspend_noirq,
	imx7ulp_wdt_resume_noirq)
	};

	static const struct imx_wdt_hw_feature imx7ulp_wdt_hw = {
	.prescaler_enable = false,
	.wdog_clock_rate = 1000,
	};

	static const struct imx_wdt_hw_feature imx93_wdt_hw = {
	.prescaler_enable = true,
	.wdog_clock_rate = 125,
	};

	static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
	{ .compatible = "fsl,imx8ulp-wdt", .data = &imx7ulp_wdt_hw, },
	{ .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, },
	{ .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);

	static struct platform_driver imx7ulp_wdt_driver = {
	.probe = imx7ulp_wdt_probe,
	.driver = {
	.name = "imx7ulp-wdt",
	.pm = &imx7ulp_wdt_pm_ops,
	.of_match_table = imx7ulp_wdt_dt_ids,
	},
	};
	module_platform_driver(imx7ulp_wdt_driver);

	MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
	MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver");
	MODULE_LICENSE("GPL v2");