Re: [PATCH V2 2/3] watchdog: atcwdt200: Add driver for Andes ATCWDT200

[Guenter Roeck]

On Thu, Jan 15, 2026 at 04:14:43PM +0800, CL Wang wrote:
> Add support for the Andes ATCWDT200 watchdog timer. The driver implements
> programmable reset and interrupt timers, and includes automatic detection
> of the supported IntTime bit-width.
> 
> Integrated with the Linux watchdog framework, it supports basic operations
> including start, stop, ping, timeout configuration, and system reset via the
> restart handler.
> 
> Signed-off-by: CL Wang <cl634@xxxxxxxxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
> Changes in v2:
>   - Use devm_clk_get_enabled() instead of devm_clk_get() and
>     clk_prepare_enable()
>   - Drop unnecessary "andestech,qilai-wdt" compatible
>   - Remove .owner assignment from platform_driver
>   - Simplify resume error handling
> ---
>  drivers/watchdog/Kconfig         |   9 +
>  drivers/watchdog/Makefile        |   1 +
>  drivers/watchdog/atcwdt200_wdt.c | 580 +++++++++++++++++++++++++++++++
>  3 files changed, 590 insertions(+)
>  create mode 100644 drivers/watchdog/atcwdt200_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index d3b9df7d466b..f5d3c1227385 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -2140,6 +2140,15 @@ config WATCHDOG_RTAS
>  
>  # RISC-V Architecture
>  
> +config ATCWDT200_WATCHDOG
> +	tristate "Andes ATCWDT200 Watchdog support"
> +	depends on ARCH_ANDES || COMPILE_TEST
> +	help
> +	  Driver for the Andes ATCWDT200 watchdog timer. It provides access to
> +	  programmable reset and interrupt counters with clock-source dependent
> +	  timing. The driver automatically detects the supported IntTime bit-width
> +	  and is fully integrated with the Linux Watchdog Framework.
> +
>  config STARFIVE_WATCHDOG
>  	tristate "StarFive Watchdog support"
>  	depends on ARCH_STARFIVE || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index ba52099b1253..aaecf7899380 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -201,6 +201,7 @@ obj-$(CONFIG_PSERIES_WDT) += pseries-wdt.o
>  obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
>  
>  # RISC-V Architecture
> +obj-$(CONFIG_ATCWDT200_WATCHDOG) += atcwdt200_wdt.o
>  obj-$(CONFIG_STARFIVE_WATCHDOG) += starfive-wdt.o
>  
>  # S390 Architecture
> diff --git a/drivers/watchdog/atcwdt200_wdt.c b/drivers/watchdog/atcwdt200_wdt.c
> new file mode 100644
> index 000000000000..8e3b18aea368
> --- /dev/null
> +++ b/drivers/watchdog/atcwdt200_wdt.c
> @@ -0,0 +1,580 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Andes ATCWDT200 watchdog timer driver.
> + *
> + * Copyright (C) 2025 Andes Technology Corporation
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/dev_printk.h>
> +#include <linux/math64.h>
> +#include <linux/minmax.h>
> +#include <linux/moduleparam.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/watchdog.h>
> +
> +/* Register definitions */
> +#define REG_CTRL		0x10
> +#define REG_RESTART		0x14
> +#define REG_WRITE_EN		0x18
> +#define REG_STATUS		0x1C
> +
> +/* Control Register */
> +#define CTRL_RST_TIME_MSK	GENMASK(10, 8)
> +#define CTRL_RST_TIME_SET(x)	FIELD_PREP(CTRL_RST_TIME_MSK, x)
> +#define CTRL_INT_TIME_MSK	GENMASK(7, 4)
> +#define CTRL_INT_TIME_SET(x)	FIELD_PREP(CTRL_INT_TIME_MSK, x)
> +#define CTRL_INT_TIME_GET(x)	FIELD_GET(CTRL_INT_TIME_MSK, x)
> +#define CTRL_RST_EN		BIT(3)
> +#define CTRL_CLK_SEL		BIT(1)
> +#define CTRL_CLK_SEL_PCLK	1
> +#define CTRL_CLK_SEL_SET(x)	FIELD_PREP(CTRL_CLK_SEL, x)
> +#define CTRL_WDT_EN		BIT(0)
> +
> +/* Restart Register */
> +#define RESTART_MAGIC		0xCAFE
> +
> +/* Write Enable Register */
> +#define WRITE_EN_MAGIC		0x5AA5
> +
> +/* Status Register */
> +#define STATUS_INT_EXPIRED	BIT(1)
> +
> +/* The default timeout value in seconds */
> +#define ATCWDT_TIMEOUT		4
> +
> +/* Define the array size for each timer type */
> +#define TMR_SZ_RST		8
> +#define TMR_SZ_INT_16		8
> +#define TMR_SZ_INT_32		16
> +
> +#define DRV_NAME		"atcwdt200"
> +/**
> + * enum timer_type - Supported timer types for ATCWDT200 watchdog driver
> + * @TMR_RST:      Reset timer (non-interrupt).
> + * @TMR_INT_16:   16-bit interrupt timer supported by hardware.
> + * @TMR_INT_32:   32-bit interrupt timer supported by hardware.
> + * @TMR_UNKNOWN:  Timer type cannot be determined.
> + */
> +enum timer_type {
> +	TMR_RST,
> +	TMR_INT_16,
> +	TMR_INT_32,
> +	TMR_UNKNOWN
> +};
> +
> +static unsigned int timeout = ATCWDT_TIMEOUT;
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +
> +/**
> + * struct atcwdt_drv - ATCWDT200 watchdog driver private data
> + * @wdt_dev:        Watchdog device used by the watchdog framework.
> + * @regmap:         Register map for accessing hardware registers.
> + * @clk:            Hardware clock used by the watchdog timer.
> + * @lock:           Spinlock protecting register accesses and driver state.
> + * @clk_freq:       Input clock frequency of the ATCWDT200.
> + * @clk_src:        Selected clock source for the watchdog timer.
> + * @int_timer_type: Detected interrupt timer type (16-bit, 32-bit, or unknown).
> + */
> +struct atcwdt_drv {
> +	struct watchdog_device	wdt_dev;
> +	struct regmap		*regmap;
> +	struct clk		*clk;
> +	spinlock_t		lock;
> +	unsigned int		clk_freq;
> +	unsigned char		clk_src;
> +	unsigned char		int_timer_type;
> +};
> +
> +static const struct watchdog_info atcwdt_info = {
> +	.identity = DRV_NAME,
> +	.options = WDIOF_SETTIMEOUT |
> +		   WDIOF_KEEPALIVEPING |
> +		   WDIOF_MAGICCLOSE,
> +};
> +
> +/**
> + * atcwdt_get_index - Get the interval value for the specified timer type
> + * @index: The index of the interval in the array
> + * @timer_type: The type of timer, which can be TMR_RST, TMR_INT_16, or
> + *              TMR_INT_32.
> + *
> + * This function retrieves the interval value based on the timer type and
> + * ensures the index stays within the valid range for the given timer type.
> + * For TMR_RST:
> + *  - The maximum array size is 8 (index range: 0-7).
> + * For TMR_INT_16:
> + *  - The maximum array size is 8 (index range: 0-7).
> + * For TMR_INT_32:
> + *  - The maximum array size is 16 (index range: 0-15).
> + *
> + * If the index exceeds the maximum array size, the function will return
> + * the last element of the respective array.
> + */
> +static inline unsigned char atcwdt_get_index(unsigned char index,
> +					     enum timer_type timer_type)
> +{
> +	static const unsigned char rst_timer_interval[TMR_SZ_RST] = {
> +		7, 8, 9, 10, 11, 12, 13, 14};
> +	static const unsigned char int_timer_interval[TMR_SZ_INT_32] = {
> +		6, 8, 10, 11, 12, 13, 14, 15, 17, 19, 21, 23, 25, 27, 29, 31};
> +	unsigned char array_index;
> +
> +	if (timer_type == TMR_RST) {
> +		array_index = min(index, TMR_SZ_RST - 1);
> +		return rst_timer_interval[array_index];
> +	}
> +
> +	if (timer_type == TMR_INT_32)
> +		array_index = min(index, TMR_SZ_INT_32 - 1);
> +	else
> +		array_index = min(index, TMR_SZ_INT_16 - 1);
> +
> +	return int_timer_interval[array_index];
> +}
> +
> +/**
> + * atcwdt_get_clock_period - Calculate the closest clock period based on a
> + *                           given tick count
> + * @tick: The target tick count to match
> + * @timer_type: The type of timer, which can be TMR_RST, TMR_INT_16, or
> + *              TMR_INT_32.
> + * @index: Pointer to store the index of the selected parameter
> + *
> + * This function calculates the closest clock period to the given tick count
> + * by iterating through the timer parameters and selecting the one that
> + * minimizes the difference between the target tick count and the calculated
> + * clock period. The function determines the index of the closest parameter
> + * and returns the difference between the target tick count and the selected
> + * clock period.
> + *
> + * Return: The difference between the target tick count and the selected
> + * clock period.
> + */
> +static long long atcwdt_get_clock_period(long long tick,
> +					 enum timer_type timer_type,
> +					 unsigned char *index)
> +{
> +	long long result;
> +	unsigned char size;
> +	char i;
> +
> +	if (timer_type == TMR_RST)
> +		size = TMR_SZ_RST;
> +	else if (timer_type == TMR_INT_32)
> +		size = TMR_SZ_INT_32;
> +	else
> +		size = TMR_SZ_INT_16;
> +
> +	*index = size - 1;
> +	for (i = 0; i < size; i++) {
> +		result = tick - (1LL << atcwdt_get_index(i, timer_type));
> +
> +		if (result <= 1) {
> +			*index = i;
> +			break;
> +		}
> +	}
> +
> +	return result;
> +}
> +
> +/**
> + * atcwdt_get_timeout_params - Calculate optimal parameters for Watchdog Timer
> + * @drv_data: Pointer to the Watchdog driver data structure
> + * @timeout: Desired timeout value (in seconds)
> + * @int_timer_params: Pointer to store the calculated interrupt timer
> + *                    parameter index
> + * @rst_timer_params: Pointer to store the calculated reset timer parameter
> + *                    index
> + *
> + * This function calculates the optimal parameter combination for the
> + * interrupt timer and reset timer of the Watchdog Timer to achieve a
> + * timeout value closest to, but not less than the specified timeout.
> + *
> + * Algorithm:
> + * 1. The parameters for both the interrupt timer and reset timer are
> + *    predefined as a series of options represented as powers of 2.
> + * 2. The function first determines the interrupt timer's parameter index
> + *    that provides a time closest to and not exceeding the desired timeout.
> + * 3. Based on the selected interrupt timer, it calculates the required
> + *    reset timer parameter to ensure the total timeout matches the target.
> + *
> + * Return: The calculated parameter indices are stored in the provided
> + *         pointers.
> + */
> +static void atcwdt_get_timeout_params(struct atcwdt_drv *drv_data,
> +				      unsigned int timeout,
> +				      unsigned char *int_timer_params,
> +				      unsigned char *rst_timer_params)
> +{
> +	long long rest_time_ms;
> +	long long result;
> +	long long tick;
> +	unsigned char rst_index;
> +	unsigned char int_index;
> +	unsigned char above;
> +	unsigned char below;
> +
> +	tick = (long long)timeout * drv_data->clk_freq;
> +	result = atcwdt_get_clock_period(tick,
> +					 drv_data->int_timer_type,
> +					 &above);
> +	if (result == 0 || above == 0) {
> +		*int_timer_params = above;
> +		*rst_timer_params = 0;
> +		return;
> +	}
> +	below = above - 1;
> +
> +	int_index = atcwdt_get_index(below, drv_data->int_timer_type);
> +	rest_time_ms = timeout * 1000LL
> +		       - div64_s64(1000LL << int_index, drv_data->clk_freq);
> +
> +	result = atcwdt_get_clock_period(rest_time_ms * drv_data->clk_freq,
> +					 TMR_RST,
> +					 &rst_index);
> +
> +	if (result > 1) {
> +		*int_timer_params = above;
> +		*rst_timer_params = 0;
> +	} else {
> +		*int_timer_params = below;
> +		*rst_timer_params = rst_index;
> +	}
> +}
> +
> +/**
> + * atcwdt_get_int_timer_type - Get the supported interrupt timer type.
> + * @drv_data: Pointer to the watchdog driver data structure.
> + *
> + * This function tests the writable bits in the IntTime field of the control
> + * register to determine the interrupt timer type supported by the hardware.
> + *
> + * Note: This function must only be called when the ATCWDT200 watchdog is
> + * disabled. If the watchdog is enabled, this function returns TMR_UNKNOWN.
> + *
> + * Returns: The interrupt timer type supported by the hardware.
> + */
> +static int atcwdt_get_int_timer_type(struct atcwdt_drv *drv_data)
> +{
> +	struct device *dev = drv_data->wdt_dev.parent;
> +	unsigned int val;
> +	int ret  = 0;
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_read(drv_data->regmap, REG_CTRL, &val);
> +	if (val & CTRL_WDT_EN) {
> +		spin_unlock(&drv_data->lock);
> +		return TMR_UNKNOWN;
> +	}
> +
> +	/*
> +	 * Configures the IntTime field with the maximum mask value
> +	 * (CTRL_INT_TIME_MSK), reads its value from the control register
> +	 * to identify the maximum writable bits.
> +	 */
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +	regmap_write(drv_data->regmap, REG_CTRL, CTRL_INT_TIME_MSK);
> +	regmap_read(drv_data->regmap, REG_CTRL, &val);
> +	spin_unlock(&drv_data->lock);
> +
> +	val = CTRL_INT_TIME_GET(val);
> +	switch (val) {
> +	case 7:
> +		drv_data->int_timer_type = TMR_INT_16;
> +		break;
> +	case 15:
> +		drv_data->int_timer_type = TMR_INT_32;
> +		break;
> +	default:
> +		drv_data->int_timer_type = TMR_UNKNOWN;
> +		ret = dev_err_probe(dev, -ENODEV,
> +				    "Failed to detect interrupt timer type\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static int atcwdt_ping(struct watchdog_device *wdt_dev)
> +{
> +	struct atcwdt_drv *drv_data = watchdog_get_drvdata(wdt_dev);
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +	regmap_write(drv_data->regmap, REG_RESTART, RESTART_MAGIC);
> +	regmap_update_bits(drv_data->regmap, REG_STATUS, STATUS_INT_EXPIRED,
> +			   STATUS_INT_EXPIRED);
> +	spin_unlock(&drv_data->lock);
> +
> +	return 0;
> +}
> +
> +static int atcwdt_set_timeout(struct watchdog_device *wdt_dev,
> +			      unsigned int timeout)
> +{
> +	struct atcwdt_drv *drv_data = watchdog_get_drvdata(wdt_dev);
> +	unsigned int value;
> +	unsigned char  rst_val;
> +	unsigned char  int_val;
> +
> +	wdt_dev->timeout = timeout;
> +	atcwdt_get_timeout_params(drv_data, timeout, &int_val, &rst_val);
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +
> +	value = CTRL_RST_TIME_SET(rst_val) |
> +		CTRL_INT_TIME_SET(int_val) |
> +		CTRL_CLK_SEL_SET(drv_data->clk_src);
> +	regmap_update_bits(drv_data->regmap,
> +			   REG_CTRL,
> +			   CTRL_RST_TIME_MSK |
> +			   CTRL_INT_TIME_MSK |
> +			   CTRL_CLK_SEL,
> +			   value);
> +
> +	spin_unlock(&drv_data->lock);
> +	atcwdt_ping(wdt_dev);
> +
> +	return 0;
> +}
> +
> +static int atcwdt_start(struct watchdog_device *wdt_dev)
> +{
> +	struct atcwdt_drv *drv_data = watchdog_get_drvdata(wdt_dev);
> +
> +	atcwdt_set_timeout(wdt_dev, wdt_dev->timeout);
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +	regmap_update_bits(drv_data->regmap,
> +			   REG_CTRL,
> +			   CTRL_RST_EN | CTRL_WDT_EN,
> +			   CTRL_RST_EN | CTRL_WDT_EN);
> +
> +	spin_unlock(&drv_data->lock);
> +
> +	return 0;
> +}
> +
> +static int atcwdt_stop(struct watchdog_device *wdt_dev)
> +{
> +	struct atcwdt_drv *drv_data = watchdog_get_drvdata(wdt_dev);
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +	regmap_update_bits(drv_data->regmap,
> +			   REG_CTRL,
> +			   CTRL_RST_EN | CTRL_WDT_EN,
> +			   0);
> +	spin_unlock(&drv_data->lock);
> +
> +	return 0;
> +}
> +
> +static int atcwdt_restart(struct watchdog_device *wdt_dev,
> +			  unsigned long action, void *data)
> +{
> +	struct atcwdt_drv *drv_data = watchdog_get_drvdata(wdt_dev);
> +
> +	atcwdt_set_timeout(wdt_dev, 0);
> +
> +	spin_lock(&drv_data->lock);
> +	regmap_write(drv_data->regmap, REG_WRITE_EN, WRITE_EN_MAGIC);
> +	regmap_update_bits(drv_data->regmap,
> +			   REG_CTRL,
> +			   CTRL_RST_EN | CTRL_WDT_EN,
> +			   CTRL_RST_EN | CTRL_WDT_EN);
> +	spin_unlock(&drv_data->lock);
> +
> +	return 0;
> +}
> +
> +static const struct watchdog_ops atcwdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = atcwdt_start,
> +	.stop = atcwdt_stop,
> +	.ping = atcwdt_ping,
> +	.set_timeout = atcwdt_set_timeout,
> +	.restart = atcwdt_restart,
> +};
> +
> +static int atcwdt_init_resource(struct platform_device *pdev,
> +				struct atcwdt_drv *drv_data)
> +{
> +	struct device *dev = &pdev->dev;
> +	void __iomem *base;
> +	const struct regmap_config cfg = {
> +		.name = "atcwdt",
> +		.reg_bits = 32,
> +		.val_bits = 32,
> +		.cache_type = REGCACHE_NONE,
> +		.reg_stride = 4,
> +		.max_register = REG_STATUS,
> +	};
> +
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return dev_err_probe(dev, PTR_ERR(base),
> +				     "Failed to ioremap I/O resource\n");
> +
> +	drv_data->regmap = devm_regmap_init_mmio(dev, base, &cfg);
> +	if (IS_ERR(drv_data->regmap))
> +		return dev_err_probe(dev, PTR_ERR(drv_data->regmap),
> +				     "Failed to create regmap\n");
> +
> +	return 0;
> +}
> +
> +static int atcwdt_enable_clk(struct atcwdt_drv *drv_data)
> +{
> +	struct device *dev = drv_data->wdt_dev.parent;
> +	unsigned int val;
> +	int clk_src;
> +
> +	drv_data->clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(drv_data->clk))
> +		return dev_err_probe(dev, PTR_ERR(drv_data->clk),
> +				     "Failed to get watchdog clock\n");
> +
> +	drv_data->clk_freq = clk_get_rate(drv_data->clk);
> +	if (!drv_data->clk_freq)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Failed to get clock rate\n");
> +
> +	clk_src = device_property_read_u32(dev, "andestech,clock-source", &val);
> +	drv_data->clk_src = (!clk_src && val != 0) ? CTRL_CLK_SEL_PCLK : 0;
> +
> +	return 0;
> +}
> +
> +static int atcwdt_init_wdt_device(struct device *dev,
> +				  struct atcwdt_drv *drv_data)
> +{
> +	struct watchdog_device *wdd = &drv_data->wdt_dev;
> +
> +	wdd->parent = dev;
> +	wdd->info = &atcwdt_info;
> +	wdd->ops = &atcwdt_ops;
> +	wdd->timeout = ATCWDT_TIMEOUT;
> +	wdd->min_timeout = 1;
> +
> +	watchdog_set_nowayout(wdd, nowayout);
> +	watchdog_set_drvdata(wdd, drv_data);
> +
> +	return 0;
> +}
> +
> +static void atcwdt_calc_max_timeout(struct atcwdt_drv *drv_data)
> +{
> +	unsigned char rst_idx = atcwdt_get_index(0xFF, TMR_RST);
> +	unsigned char int_idx = atcwdt_get_index(0xFF,
> +						 drv_data->int_timer_type);
> +
> +	drv_data->wdt_dev.max_timeout =
> +		((1U << rst_idx) + (1U << int_idx)) / drv_data->clk_freq;
> +}
> +
> +static int atcwdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct atcwdt_drv *drv_data;
> +	int ret;
> +
> +	drv_data = devm_kzalloc(dev, sizeof(*drv_data), GFP_KERNEL);
> +	if (!drv_data)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, drv_data);
> +	spin_lock_init(&drv_data->lock);
> +
> +	ret = atcwdt_init_wdt_device(dev, drv_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = atcwdt_init_resource(pdev, drv_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = atcwdt_enable_clk(drv_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = atcwdt_get_int_timer_type(drv_data);
> +	if (ret)
> +		return ret;
> +
> +	atcwdt_calc_max_timeout(drv_data);
> +
> +	ret = devm_watchdog_register_device(dev, &drv_data->wdt_dev);
> +
> +	return ret;
> +}
> +
> +static int atcwdt_suspend(struct device *dev)
> +{
> +	struct atcwdt_drv *drv_data = dev_get_drvdata(dev);
> +
> +	if (watchdog_active(&drv_data->wdt_dev)) {
> +		atcwdt_stop(&drv_data->wdt_dev);
> +		clk_disable_unprepare(drv_data->clk);
> +	}
> +
> +	return 0;
> +}
> +
> +static int atcwdt_resume(struct device *dev)
> +{
> +	struct atcwdt_drv *drv_data = dev_get_drvdata(dev);
> +	int ret = 0;
> +
> +	if (watchdog_active(&drv_data->wdt_dev)) {
> +		ret = clk_prepare_enable(drv_data->clk);
> +		if (ret)
> +			return ret;
> +		atcwdt_start(&drv_data->wdt_dev);
> +		atcwdt_ping(&drv_data->wdt_dev);
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id atcwdt_match[] = {
> +	{ .compatible = "andestech,ae350-wdt" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, atcwdt_match);
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(atcwdt_pm_ops, atcwdt_suspend, atcwdt_resume);
> +
> +static struct platform_driver atcwdt_driver = {
> +	.probe = atcwdt_probe,
> +	.driver = {
> +		.name = DRV_NAME,
> +		.of_match_table = atcwdt_match,
> +		.pm = pm_sleep_ptr(&atcwdt_pm_ops),
> +	},
> +};
> +
> +module_platform_driver(atcwdt_driver);
> +
> +module_param(timeout, uint, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
> +		 __MODULE_STRING(ATCWDT_TIMEOUT) ")");
> +
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("CL Wang <cl634@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Andes ATCWDT200 Watchdog timer driver");