[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/of_gpio.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 {
	int			gpio;
	bool			active_low;
	bool			state;
	bool			always_running;
	unsigned int		hw_algo;
	struct watchdog_device	wdd;
};

static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
{
	gpio_set_value_cansleep(priv->gpio, !priv->active_low);

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

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;
		gpio_set_value_cansleep(priv->gpio, priv->state);
		break;
	case HW_ALGO_LEVEL:
		/* Pulse */
		gpio_set_value_cansleep(priv->gpio, !priv->active_low);
		udelay(1);
		gpio_set_value_cansleep(priv->gpio, priv->active_low);
		break;
	}
	return 0;
}

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

	priv->state = priv->active_low;
	gpio_direction_output(priv->gpio, 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);
		clear_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 gpio_wdt_priv *priv;
	enum of_gpio_flags flags;
	unsigned int hw_margin;
	unsigned long f = 0;
	const char *algo;
	int ret;

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

	platform_set_drvdata(pdev, priv);

	priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
	if (!gpio_is_valid(priv->gpio))
		return priv->gpio;

	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;

	ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo);
	if (ret)
		return ret;
	if (!strcmp(algo, "toggle")) {
		priv->hw_algo = HW_ALGO_TOGGLE;
		f = GPIOF_IN;
	} else if (!strcmp(algo, "level")) {
		priv->hw_algo = HW_ALGO_LEVEL;
		f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
	} else {
		return -EINVAL;
	}

	ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f,
				    dev_name(&pdev->dev));
	if (ret)
		return ret;

	ret = of_property_read_u32(pdev->dev.of_node,
				   "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(pdev->dev.of_node,
						     "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	= &pdev->dev;

	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
		priv->wdd.timeout = SOFT_TIMEOUT_DEF;

	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>
25134eaf AS	15	#include <linux/of_gpio.h>
25134eaf AS	16	#include <linux/platform_device.h>
25134eaf AS	17	#include <linux/watchdog.h>
	18
	19	#define SOFT_TIMEOUT_MIN 1
	20	#define SOFT_TIMEOUT_DEF 60
25134eaf AS	21
	22	enum {
	23	HW_ALGO_TOGGLE,
	24	HW_ALGO_LEVEL,
	25	};
	26
	27	struct gpio_wdt_priv {
	28	int gpio;
	29	bool active_low;
	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	{
	38	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
	39
	40	/* Put GPIO back to tristate */
	41	if (priv->hw_algo == HW_ALGO_TOGGLE)
	42	gpio_direction_input(priv->gpio);
	43	}
	44
03bca158	45	static int gpio_wdt_ping(struct watchdog_device *wdd)
4f2d0b2d	46	{
4f2d0b2d UKK	47	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
4f2d0b2d UKK	48
4f2d0b2d UKK	49	switch (priv->hw_algo) {
	50	case HW_ALGO_TOGGLE:
	51	/* Toggle output pin */
	52	priv->state = !priv->state;
	53	gpio_set_value_cansleep(priv->gpio, priv->state);
	54	break;
	55	case HW_ALGO_LEVEL:
	56	/* Pulse */
	57	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
	58	udelay(1);
	59	gpio_set_value_cansleep(priv->gpio, priv->active_low);
	60	break;
	61	}
03bca158	62	return 0;
ba804a95 ML	63	}
	64
	65	static int gpio_wdt_start(struct watchdog_device *wdd)
	66	{
	67	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	68
03bca158 GR	69	priv->state = priv->active_low;
03bca158 GR	70	gpio_direction_output(priv->gpio, priv->state);
25134eaf	71
03bca158 GR	72	set_bit(WDOG_HW_RUNNING, &wdd->status);
	73
	74	return gpio_wdt_ping(wdd);
25134eaf AS	75	}
	76
	77	static int gpio_wdt_stop(struct watchdog_device *wdd)
	78	{
	79	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	80
ba804a95	81	if (!priv->always_running) {
ba804a95	82	gpio_wdt_disable(priv);
03bca158	83	clear_bit(WDOG_HW_RUNNING, &wdd->status);
ba804a95	84	}
25134eaf AS	85
	86	return 0;
	87	}
	88
25134eaf AS	89	static const struct watchdog_info gpio_wdt_ident = {
	90	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \|
	91	WDIOF_SETTIMEOUT,
	92	.identity = "GPIO Watchdog",
	93	};
	94
	95	static const struct watchdog_ops gpio_wdt_ops = {
	96	.owner = THIS_MODULE,
	97	.start = gpio_wdt_start,
	98	.stop = gpio_wdt_stop,
	99	.ping = gpio_wdt_ping,
25134eaf AS	100	};
	101
	102	static int gpio_wdt_probe(struct platform_device *pdev)
	103	{
	104	struct gpio_wdt_priv *priv;
	105	enum of_gpio_flags flags;
	106	unsigned int hw_margin;
	107	unsigned long f = 0;
	108	const char *algo;
	109	int ret;
	110
	111	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	112	if (!priv)
	113	return -ENOMEM;
	114
1ac06563 WY	115	platform_set_drvdata(pdev, priv);
1ac06563 WY	116
25134eaf AS	117	priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
	118	if (!gpio_is_valid(priv->gpio))
	119	return priv->gpio;
	120
	121	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;
	122
	123	ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo);
	124	if (ret)
	125	return ret;
0a0a542f	126	if (!strcmp(algo, "toggle")) {
25134eaf AS	127	priv->hw_algo = HW_ALGO_TOGGLE;
25134eaf AS	128	f = GPIOF_IN;
0a0a542f	129	} else if (!strcmp(algo, "level")) {
25134eaf AS	130	priv->hw_algo = HW_ALGO_LEVEL;
	131	f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
	132	} else {
	133	return -EINVAL;
	134	}
	135
	136	ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f,
	137	dev_name(&pdev->dev));
	138	if (ret)
	139	return ret;
	140
	141	ret = of_property_read_u32(pdev->dev.of_node,
	142	"hw_margin_ms", &hw_margin);
	143	if (ret)
	144	return ret;
	145	/* Disallow values lower than 2 and higher than 65535 ms */
	146	if (hw_margin < 2 \|\| hw_margin > 65535)
	147	return -EINVAL;
	148
ba804a95 ML	149	priv->always_running = of_property_read_bool(pdev->dev.of_node,
	150	"always-running");
	151
25134eaf AS	152	watchdog_set_drvdata(&priv->wdd, priv);
	153
	154	priv->wdd.info = &gpio_wdt_ident;
	155	priv->wdd.ops = &gpio_wdt_ops;
	156	priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
03bca158	157	priv->wdd.max_hw_heartbeat_ms = hw_margin;
6551881c	158	priv->wdd.parent = &pdev->dev;
25134eaf AS	159
	160	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
	161	priv->wdd.timeout = SOFT_TIMEOUT_DEF;
	162
28e805b4 DR	163	watchdog_stop_on_reboot(&priv->wdd);
28e805b4 DR	164
ba804a95	165	if (priv->always_running)
03bca158	166	gpio_wdt_start(&priv->wdd);
ba804a95	167
03bca158 GR	168	ret = watchdog_register_device(&priv->wdd);
	169
	170	return ret;
25134eaf AS	171	}
	172
	173	static int gpio_wdt_remove(struct platform_device *pdev)
	174	{
	175	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
	176
25134eaf AS	177	watchdog_unregister_device(&priv->wdd);
	178
	179	return 0;
	180	}
	181
	182	static const struct of_device_id gpio_wdt_dt_ids[] = {
	183	{ .compatible = "linux,wdt-gpio", },
	184	{ }
	185	};
	186	MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
	187
	188	static struct platform_driver gpio_wdt_driver = {
	189	.driver = {
	190	.name = "gpio-wdt",
25134eaf AS	191	.of_match_table = gpio_wdt_dt_ids,
	192	},
	193	.probe = gpio_wdt_probe,
	194	.remove = gpio_wdt_remove,
	195	};
5e53c8ed JBT	196
	197	#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
	198	static int __init gpio_wdt_init(void)
	199	{
	200	return platform_driver_register(&gpio_wdt_driver);
	201	}
	202	arch_initcall(gpio_wdt_init);
	203	#else
25134eaf	204	module_platform_driver(gpio_wdt_driver);
5e53c8ed	205	#endif
25134eaf AS	206
	207	MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
	208	MODULE_DESCRIPTION("GPIO Watchdog");
	209	MODULE_LICENSE("GPL");