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

/*
 * Driver for watchdog device controlled through GPIO-line
 *
 * Author: 2013, Alexander Shiyan <shc_work@mail.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

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

#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 device_node *np = dev->of_node;
	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 = of_property_read_string(np, "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 = of_property_read_u32(np,
				   "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 = of_property_read_bool(np,
						     "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, &pdev->dev);

	watchdog_stop_on_reboot(&priv->wdd);

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

	ret = watchdog_register_device(&priv->wdd);

	return ret;
}

static int gpio_wdt_remove(struct platform_device *pdev)
{
	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);

	watchdog_unregister_device(&priv->wdd);

	return 0;
}

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,
	.remove	= gpio_wdt_remove,
};

#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
25134eaf AS	1	/*
	2	* Driver for watchdog device controlled through GPIO-line
	3	*
	4	* Author: 2013, Alexander Shiyan <shc_work@mail.ru>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*/
	11
	12	#include <linux/err.h>
	13	#include <linux/delay.h>
	14	#include <linux/module.h>
a2363f9d LW	15	#include <linux/gpio/consumer.h>
a2363f9d LW	16	#include <linux/of.h>
25134eaf	17	#include <linux/platform_device.h>
25134eaf AS	18	#include <linux/watchdog.h>
	19
	20	#define SOFT_TIMEOUT_MIN 1
	21	#define SOFT_TIMEOUT_DEF 60
25134eaf AS	22
	23	enum {
	24	HW_ALGO_TOGGLE,
	25	HW_ALGO_LEVEL,
	26	};
	27
	28	struct gpio_wdt_priv {
a2363f9d	29	struct gpio_desc *gpiod;
25134eaf	30	bool state;
ba804a95	31	bool always_running;
25134eaf	32	unsigned int hw_algo;
25134eaf AS	33	struct watchdog_device wdd;
	34	};
	35
	36	static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
	37	{
a2363f9d LW	38	/* Eternal ping */
a2363f9d LW	39	gpiod_set_value_cansleep(priv->gpiod, 1);
25134eaf AS	40
	41	/* Put GPIO back to tristate */
	42	if (priv->hw_algo == HW_ALGO_TOGGLE)
a2363f9d	43	gpiod_direction_input(priv->gpiod);
25134eaf AS	44	}
25134eaf AS	45
03bca158	46	static int gpio_wdt_ping(struct watchdog_device *wdd)
4f2d0b2d	47	{
4f2d0b2d UKK	48	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
4f2d0b2d UKK	49
4f2d0b2d UKK	50	switch (priv->hw_algo) {
	51	case HW_ALGO_TOGGLE:
	52	/* Toggle output pin */
	53	priv->state = !priv->state;
a2363f9d	54	gpiod_set_value_cansleep(priv->gpiod, priv->state);
4f2d0b2d UKK	55	break;
	56	case HW_ALGO_LEVEL:
	57	/* Pulse */
a2363f9d	58	gpiod_set_value_cansleep(priv->gpiod, 1);
4f2d0b2d	59	udelay(1);
a2363f9d	60	gpiod_set_value_cansleep(priv->gpiod, 0);
4f2d0b2d UKK	61	break;
4f2d0b2d UKK	62	}
03bca158	63	return 0;
ba804a95 ML	64	}
	65
	66	static int gpio_wdt_start(struct watchdog_device *wdd)
	67	{
	68	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	69
a2363f9d LW	70	priv->state = 0;
a2363f9d LW	71	gpiod_direction_output(priv->gpiod, priv->state);
25134eaf	72
03bca158 GR	73	set_bit(WDOG_HW_RUNNING, &wdd->status);
	74
	75	return gpio_wdt_ping(wdd);
25134eaf AS	76	}
	77
	78	static int gpio_wdt_stop(struct watchdog_device *wdd)
	79	{
	80	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	81
ba804a95	82	if (!priv->always_running) {
ba804a95	83	gpio_wdt_disable(priv);
bc137dfd RV	84	} else {
bc137dfd RV	85	set_bit(WDOG_HW_RUNNING, &wdd->status);
ba804a95	86	}
25134eaf AS	87
	88	return 0;
	89	}
	90
25134eaf AS	91	static const struct watchdog_info gpio_wdt_ident = {
	92	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \|
	93	WDIOF_SETTIMEOUT,
	94	.identity = "GPIO Watchdog",
	95	};
	96
	97	static const struct watchdog_ops gpio_wdt_ops = {
	98	.owner = THIS_MODULE,
	99	.start = gpio_wdt_start,
	100	.stop = gpio_wdt_stop,
	101	.ping = gpio_wdt_ping,
25134eaf AS	102	};
	103
	104	static int gpio_wdt_probe(struct platform_device *pdev)
	105	{
d0d0677e LW	106	struct device *dev = &pdev->dev;
d0d0677e LW	107	struct device_node *np = dev->of_node;
25134eaf	108	struct gpio_wdt_priv *priv;
a2363f9d	109	enum gpiod_flags gflags;
25134eaf	110	unsigned int hw_margin;
25134eaf AS	111	const char *algo;
	112	int ret;
	113
d0d0677e	114	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
25134eaf AS	115	if (!priv)
	116	return -ENOMEM;
	117
1ac06563 WY	118	platform_set_drvdata(pdev, priv);
1ac06563 WY	119
d0d0677e	120	ret = of_property_read_string(np, "hw_algo", &algo);
25134eaf AS	121	if (ret)
25134eaf AS	122	return ret;
0a0a542f	123	if (!strcmp(algo, "toggle")) {
25134eaf	124	priv->hw_algo = HW_ALGO_TOGGLE;
a2363f9d	125	gflags = GPIOD_IN;
0a0a542f	126	} else if (!strcmp(algo, "level")) {
25134eaf	127	priv->hw_algo = HW_ALGO_LEVEL;
a2363f9d	128	gflags = GPIOD_OUT_LOW;
25134eaf AS	129	} else {
	130	return -EINVAL;
	131	}
	132
a2363f9d LW	133	priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
	134	if (IS_ERR(priv->gpiod))
	135	return PTR_ERR(priv->gpiod);
25134eaf	136
d0d0677e	137	ret = of_property_read_u32(np,
25134eaf AS	138	"hw_margin_ms", &hw_margin);
	139	if (ret)
	140	return ret;
	141	/* Disallow values lower than 2 and higher than 65535 ms */
	142	if (hw_margin < 2 \|\| hw_margin > 65535)
	143	return -EINVAL;
	144
d0d0677e	145	priv->always_running = of_property_read_bool(np,
ba804a95 ML	146	"always-running");
ba804a95 ML	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
65adfa22	157	watchdog_init_timeout(&priv->wdd, 0, &pdev->dev);
25134eaf	158
28e805b4 DR	159	watchdog_stop_on_reboot(&priv->wdd);
28e805b4 DR	160
ba804a95	161	if (priv->always_running)
03bca158	162	gpio_wdt_start(&priv->wdd);
ba804a95	163
03bca158 GR	164	ret = watchdog_register_device(&priv->wdd);
	165
	166	return ret;
25134eaf AS	167	}
	168
	169	static int gpio_wdt_remove(struct platform_device *pdev)
	170	{
	171	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
	172
25134eaf AS	173	watchdog_unregister_device(&priv->wdd);
	174
	175	return 0;
	176	}
	177
	178	static const struct of_device_id gpio_wdt_dt_ids[] = {
	179	{ .compatible = "linux,wdt-gpio", },
	180	{ }
	181	};
	182	MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
	183
	184	static struct platform_driver gpio_wdt_driver = {
	185	.driver = {
	186	.name = "gpio-wdt",
25134eaf AS	187	.of_match_table = gpio_wdt_dt_ids,
	188	},
	189	.probe = gpio_wdt_probe,
	190	.remove = gpio_wdt_remove,
	191	};
5e53c8ed JBT	192
	193	#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
	194	static int __init gpio_wdt_init(void)
	195	{
	196	return platform_driver_register(&gpio_wdt_driver);
	197	}
	198	arch_initcall(gpio_wdt_init);
	199	#else
25134eaf	200	module_platform_driver(gpio_wdt_driver);
5e53c8ed	201	#endif
25134eaf AS	202
	203	MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
	204	MODULE_DESCRIPTION("GPIO Watchdog");
	205	MODULE_LICENSE("GPL");