[linux-2.6-block.git] / drivers / watchdog / gpio_wdt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for watchdog device controlled through GPIO-line
 *
 * Author: 2013, Alexander Shiyan <shc_work@mail.ru>
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/watchdog.h>

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) ")");

#define SOFT_TIMEOUT_MIN	1
#define SOFT_TIMEOUT_DEF	60

enum {
	HW_ALGO_TOGGLE,
	HW_ALGO_LEVEL,
};

struct gpio_wdt_priv {
	struct gpio_desc	*gpiod;
	bool			state;
	bool			always_running;
	unsigned int		hw_algo;
	struct watchdog_device	wdd;
};

static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
{
	/* Eternal ping */
	gpiod_set_value_cansleep(priv->gpiod, 1);

	/* Put GPIO back to tristate */
	if (priv->hw_algo == HW_ALGO_TOGGLE)
		gpiod_direction_input(priv->gpiod);
}

static int gpio_wdt_ping(struct watchdog_device *wdd)
{
	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);

	switch (priv->hw_algo) {
	case HW_ALGO_TOGGLE:
		/* Toggle output pin */
		priv->state = !priv->state;
		gpiod_set_value_cansleep(priv->gpiod, priv->state);
		break;
	case HW_ALGO_LEVEL:
		/* Pulse */
		gpiod_set_value_cansleep(priv->gpiod, 1);
		udelay(1);
		gpiod_set_value_cansleep(priv->gpiod, 0);
		break;
	}
	return 0;
}

static int gpio_wdt_start(struct watchdog_device *wdd)
{
	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);

	priv->state = 0;
	gpiod_direction_output(priv->gpiod, priv->state);

	set_bit(WDOG_HW_RUNNING, &wdd->status);

	return gpio_wdt_ping(wdd);
}

static int gpio_wdt_stop(struct watchdog_device *wdd)
{
	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);

	if (!priv->always_running) {
		gpio_wdt_disable(priv);
	} else {
		set_bit(WDOG_HW_RUNNING, &wdd->status);
	}

	return 0;
}

static const struct watchdog_info gpio_wdt_ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
			  WDIOF_SETTIMEOUT,
	.identity	= "GPIO Watchdog",
};

static const struct watchdog_ops gpio_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= gpio_wdt_start,
	.stop		= gpio_wdt_stop,
	.ping		= gpio_wdt_ping,
};

static int gpio_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct gpio_wdt_priv *priv;
	enum gpiod_flags gflags;
	unsigned int hw_margin;
	const char *algo;
	int ret;

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

	platform_set_drvdata(pdev, priv);

	ret = device_property_read_string(dev, "hw_algo", &algo);
	if (ret)
		return ret;
	if (!strcmp(algo, "toggle")) {
		priv->hw_algo = HW_ALGO_TOGGLE;
		gflags = GPIOD_IN;
	} else if (!strcmp(algo, "level")) {
		priv->hw_algo = HW_ALGO_LEVEL;
		gflags = GPIOD_OUT_LOW;
	} else {
		return -EINVAL;
	}

	priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
	if (IS_ERR(priv->gpiod))
		return PTR_ERR(priv->gpiod);

	ret = device_property_read_u32(dev, "hw_margin_ms", &hw_margin);
	if (ret)
		return ret;
	/* Disallow values lower than 2 and higher than 65535 ms */
	if (hw_margin < 2 || hw_margin > 65535)
		return -EINVAL;

	priv->always_running = device_property_read_bool(dev, "always-running");

	watchdog_set_drvdata(&priv->wdd, priv);

	priv->wdd.info		= &gpio_wdt_ident;
	priv->wdd.ops		= &gpio_wdt_ops;
	priv->wdd.min_timeout	= SOFT_TIMEOUT_MIN;
	priv->wdd.max_hw_heartbeat_ms = hw_margin;
	priv->wdd.parent	= dev;
	priv->wdd.timeout	= SOFT_TIMEOUT_DEF;

	watchdog_init_timeout(&priv->wdd, 0, dev);
	watchdog_set_nowayout(&priv->wdd, nowayout);

	watchdog_stop_on_reboot(&priv->wdd);

	if (priv->always_running)
		gpio_wdt_start(&priv->wdd);

	return devm_watchdog_register_device(dev, &priv->wdd);
}

static const struct of_device_id gpio_wdt_dt_ids[] = {
	{ .compatible = "linux,wdt-gpio", },
	{ }
};
MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);

static struct platform_driver gpio_wdt_driver = {
	.driver	= {
		.name		= "gpio-wdt",
		.of_match_table	= gpio_wdt_dt_ids,
	},
	.probe	= gpio_wdt_probe,
};

#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
static int __init gpio_wdt_init(void)
{
	return platform_driver_register(&gpio_wdt_driver);
}
arch_initcall(gpio_wdt_init);
#else
module_platform_driver(gpio_wdt_driver);
#endif

MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("GPIO Watchdog");
MODULE_LICENSE("GPL");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
25134eaf AS	2	/*
	3	* Driver for watchdog device controlled through GPIO-line
	4	*
	5	* Author: 2013, Alexander Shiyan <shc_work@mail.ru>
25134eaf AS	6	*/
25134eaf AS	7
25134eaf	8	#include <linux/delay.h>
7e5bca6e	9	#include <linux/err.h>
a2363f9d	10	#include <linux/gpio/consumer.h>
7e5bca6e AS	11	#include <linux/mod_devicetable.h>
7e5bca6e AS	12	#include <linux/module.h>
25134eaf	13	#include <linux/platform_device.h>
7e5bca6e	14	#include <linux/property.h>
25134eaf AS	15	#include <linux/watchdog.h>
25134eaf AS	16
1a4aaf9f MR	17	static bool nowayout = WATCHDOG_NOWAYOUT;
	18	module_param(nowayout, bool, 0);
	19	MODULE_PARM_DESC(nowayout,
	20	"Watchdog cannot be stopped once started (default="
	21	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	22
25134eaf AS	23	#define SOFT_TIMEOUT_MIN 1
25134eaf AS	24	#define SOFT_TIMEOUT_DEF 60
25134eaf AS	25
	26	enum {
	27	HW_ALGO_TOGGLE,
	28	HW_ALGO_LEVEL,
	29	};
	30
	31	struct gpio_wdt_priv {
a2363f9d	32	struct gpio_desc *gpiod;
25134eaf	33	bool state;
ba804a95	34	bool always_running;
25134eaf	35	unsigned int hw_algo;
25134eaf AS	36	struct watchdog_device wdd;
	37	};
	38
	39	static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
	40	{
a2363f9d LW	41	/* Eternal ping */
a2363f9d LW	42	gpiod_set_value_cansleep(priv->gpiod, 1);
25134eaf AS	43
	44	/* Put GPIO back to tristate */
	45	if (priv->hw_algo == HW_ALGO_TOGGLE)
a2363f9d	46	gpiod_direction_input(priv->gpiod);
25134eaf AS	47	}
25134eaf AS	48
03bca158	49	static int gpio_wdt_ping(struct watchdog_device *wdd)
4f2d0b2d	50	{
4f2d0b2d UKK	51	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
4f2d0b2d UKK	52
4f2d0b2d UKK	53	switch (priv->hw_algo) {
	54	case HW_ALGO_TOGGLE:
	55	/* Toggle output pin */
	56	priv->state = !priv->state;
a2363f9d	57	gpiod_set_value_cansleep(priv->gpiod, priv->state);
4f2d0b2d UKK	58	break;
	59	case HW_ALGO_LEVEL:
	60	/* Pulse */
a2363f9d	61	gpiod_set_value_cansleep(priv->gpiod, 1);
4f2d0b2d	62	udelay(1);
a2363f9d	63	gpiod_set_value_cansleep(priv->gpiod, 0);
4f2d0b2d UKK	64	break;
4f2d0b2d UKK	65	}
03bca158	66	return 0;
ba804a95 ML	67	}
	68
	69	static int gpio_wdt_start(struct watchdog_device *wdd)
	70	{
	71	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	72
a2363f9d LW	73	priv->state = 0;
a2363f9d LW	74	gpiod_direction_output(priv->gpiod, priv->state);
25134eaf	75
03bca158 GR	76	set_bit(WDOG_HW_RUNNING, &wdd->status);
	77
	78	return gpio_wdt_ping(wdd);
25134eaf AS	79	}
	80
	81	static int gpio_wdt_stop(struct watchdog_device *wdd)
	82	{
	83	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	84
ba804a95	85	if (!priv->always_running) {
ba804a95	86	gpio_wdt_disable(priv);
bc137dfd RV	87	} else {
bc137dfd RV	88	set_bit(WDOG_HW_RUNNING, &wdd->status);
ba804a95	89	}
25134eaf AS	90
	91	return 0;
	92	}
	93
25134eaf AS	94	static const struct watchdog_info gpio_wdt_ident = {
	95	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \|
	96	WDIOF_SETTIMEOUT,
	97	.identity = "GPIO Watchdog",
	98	};
	99
	100	static const struct watchdog_ops gpio_wdt_ops = {
	101	.owner = THIS_MODULE,
	102	.start = gpio_wdt_start,
	103	.stop = gpio_wdt_stop,
	104	.ping = gpio_wdt_ping,
25134eaf AS	105	};
	106
	107	static int gpio_wdt_probe(struct platform_device *pdev)
	108	{
d0d0677e	109	struct device *dev = &pdev->dev;
25134eaf	110	struct gpio_wdt_priv *priv;
a2363f9d	111	enum gpiod_flags gflags;
25134eaf	112	unsigned int hw_margin;
25134eaf AS	113	const char *algo;
	114	int ret;
	115
d0d0677e	116	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
25134eaf AS	117	if (!priv)
	118	return -ENOMEM;
	119
1ac06563 WY	120	platform_set_drvdata(pdev, priv);
1ac06563 WY	121
7e5bca6e	122	ret = device_property_read_string(dev, "hw_algo", &algo);
25134eaf AS	123	if (ret)
25134eaf AS	124	return ret;
0a0a542f	125	if (!strcmp(algo, "toggle")) {
25134eaf	126	priv->hw_algo = HW_ALGO_TOGGLE;
a2363f9d	127	gflags = GPIOD_IN;
0a0a542f	128	} else if (!strcmp(algo, "level")) {
25134eaf	129	priv->hw_algo = HW_ALGO_LEVEL;
a2363f9d	130	gflags = GPIOD_OUT_LOW;
25134eaf AS	131	} else {
	132	return -EINVAL;
	133	}
	134
a2363f9d LW	135	priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
	136	if (IS_ERR(priv->gpiod))
	137	return PTR_ERR(priv->gpiod);
25134eaf	138
7e5bca6e	139	ret = device_property_read_u32(dev, "hw_margin_ms", &hw_margin);
25134eaf AS	140	if (ret)
	141	return ret;
	142	/* Disallow values lower than 2 and higher than 65535 ms */
	143	if (hw_margin < 2 \|\| hw_margin > 65535)
	144	return -EINVAL;
	145
7e5bca6e	146	priv->always_running = device_property_read_bool(dev, "always-running");
ba804a95	147
25134eaf AS	148	watchdog_set_drvdata(&priv->wdd, priv);
	149
	150	priv->wdd.info = &gpio_wdt_ident;
	151	priv->wdd.ops = &gpio_wdt_ops;
	152	priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
03bca158	153	priv->wdd.max_hw_heartbeat_ms = hw_margin;
d0d0677e	154	priv->wdd.parent = dev;
65adfa22	155	priv->wdd.timeout = SOFT_TIMEOUT_DEF;
25134eaf	156
3564fbc5	157	watchdog_init_timeout(&priv->wdd, 0, dev);
1a4aaf9f	158	watchdog_set_nowayout(&priv->wdd, nowayout);
25134eaf	159
28e805b4 DR	160	watchdog_stop_on_reboot(&priv->wdd);
28e805b4 DR	161
ba804a95	162	if (priv->always_running)
03bca158	163	gpio_wdt_start(&priv->wdd);
ba804a95	164
3564fbc5	165	return devm_watchdog_register_device(dev, &priv->wdd);
25134eaf AS	166	}
	167
	168	static const struct of_device_id gpio_wdt_dt_ids[] = {
	169	{ .compatible = "linux,wdt-gpio", },
	170	{ }
	171	};
	172	MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
	173
	174	static struct platform_driver gpio_wdt_driver = {
	175	.driver = {
	176	.name = "gpio-wdt",
25134eaf AS	177	.of_match_table = gpio_wdt_dt_ids,
	178	},
	179	.probe = gpio_wdt_probe,
25134eaf	180	};
5e53c8ed JBT	181
	182	#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
	183	static int __init gpio_wdt_init(void)
	184	{
	185	return platform_driver_register(&gpio_wdt_driver);
	186	}
	187	arch_initcall(gpio_wdt_init);
	188	#else
25134eaf	189	module_platform_driver(gpio_wdt_driver);
5e53c8ed	190	#endif
25134eaf AS	191
	192	MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
	193	MODULE_DESCRIPTION("GPIO Watchdog");
	194	MODULE_LICENSE("GPL");