[mirror_ubuntu-bionic-kernel.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
#define SOFT_TIMEOUT_MAX	0xffff

enum {
	HW_ALGO_TOGGLE,
	HW_ALGO_LEVEL,
};

struct gpio_wdt_priv {
	int			gpio;
	bool			active_low;
	bool			state;
	bool			always_running;
	bool			armed;
	unsigned int		hw_algo;
	unsigned int		hw_margin;
	unsigned long		last_jiffies;
	struct timer_list	timer;
	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 void gpio_wdt_hwping(unsigned long data)
{
	struct watchdog_device *wdd = (struct watchdog_device *)data;
	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);

	if (priv->armed && time_after(jiffies, priv->last_jiffies +
				      msecs_to_jiffies(wdd->timeout * 1000))) {
		dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n");
		return;
	}

	/* Restart timer */
	mod_timer(&priv->timer, jiffies + priv->hw_margin);

	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;
	}
}

static void gpio_wdt_start_impl(struct gpio_wdt_priv *priv)
{
	priv->state = priv->active_low;
	gpio_direction_output(priv->gpio, priv->state);
	priv->last_jiffies = jiffies;
	gpio_wdt_hwping((unsigned long)&priv->wdd);
}

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

	gpio_wdt_start_impl(priv);
	priv->armed = true;

	return 0;
}

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

	priv->armed = false;
	if (!priv->always_running) {
		mod_timer(&priv->timer, 0);
		gpio_wdt_disable(priv);
	}

	return 0;
}

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

	priv->last_jiffies = jiffies;

	return 0;
}

static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
{
	wdd->timeout = t;

	return gpio_wdt_ping(wdd);
}

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,
	.set_timeout	= gpio_wdt_set_timeout,
};

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;

	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;

	/* Use safe value (1/2 of real timeout) */
	priv->hw_margin = msecs_to_jiffies(hw_margin / 2);

	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_timeout	= SOFT_TIMEOUT_MAX;
	priv->wdd.parent	= &pdev->dev;

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

	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);

	watchdog_stop_on_reboot(&priv->wdd);

	ret = watchdog_register_device(&priv->wdd);
	if (ret)
		return ret;

	if (priv->always_running)
		gpio_wdt_start_impl(priv);

	return 0;
}

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

	del_timer_sync(&priv->timer);
	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
	21	#define SOFT_TIMEOUT_MAX 0xffff
	22
	23	enum {
	24	HW_ALGO_TOGGLE,
	25	HW_ALGO_LEVEL,
	26	};
	27
	28	struct gpio_wdt_priv {
	29	int gpio;
	30	bool active_low;
	31	bool state;
ba804a95 ML	32	bool always_running;
ba804a95 ML	33	bool armed;
25134eaf AS	34	unsigned int hw_algo;
	35	unsigned int hw_margin;
	36	unsigned long last_jiffies;
25134eaf AS	37	struct timer_list timer;
	38	struct watchdog_device wdd;
	39	};
	40
	41	static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
	42	{
	43	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
	44
	45	/* Put GPIO back to tristate */
	46	if (priv->hw_algo == HW_ALGO_TOGGLE)
	47	gpio_direction_input(priv->gpio);
	48	}
	49
4f2d0b2d UKK	50	static void gpio_wdt_hwping(unsigned long data)
	51	{
	52	struct watchdog_device wdd = (struct watchdog_device )data;
	53	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	54
	55	if (priv->armed && time_after(jiffies, priv->last_jiffies +
	56	msecs_to_jiffies(wdd->timeout * 1000))) {
	57	dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n");
	58	return;
	59	}
	60
	61	/* Restart timer */
	62	mod_timer(&priv->timer, jiffies + priv->hw_margin);
	63
	64	switch (priv->hw_algo) {
	65	case HW_ALGO_TOGGLE:
	66	/* Toggle output pin */
	67	priv->state = !priv->state;
	68	gpio_set_value_cansleep(priv->gpio, priv->state);
	69	break;
	70	case HW_ALGO_LEVEL:
	71	/* Pulse */
	72	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
	73	udelay(1);
	74	gpio_set_value_cansleep(priv->gpio, priv->active_low);
	75	break;
	76	}
	77	}
	78
ba804a95	79	static void gpio_wdt_start_impl(struct gpio_wdt_priv *priv)
25134eaf	80	{
25134eaf AS	81	priv->state = priv->active_low;
	82	gpio_direction_output(priv->gpio, priv->state);
	83	priv->last_jiffies = jiffies;
4f2d0b2d	84	gpio_wdt_hwping((unsigned long)&priv->wdd);
ba804a95 ML	85	}
	86
	87	static int gpio_wdt_start(struct watchdog_device *wdd)
	88	{
	89	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	90
	91	gpio_wdt_start_impl(priv);
	92	priv->armed = true;
25134eaf AS	93
	94	return 0;
	95	}
	96
	97	static int gpio_wdt_stop(struct watchdog_device *wdd)
	98	{
	99	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	100
ba804a95 ML	101	priv->armed = false;
	102	if (!priv->always_running) {
	103	mod_timer(&priv->timer, 0);
	104	gpio_wdt_disable(priv);
	105	}
25134eaf AS	106
	107	return 0;
	108	}
	109
	110	static int gpio_wdt_ping(struct watchdog_device *wdd)
	111	{
	112	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	113
	114	priv->last_jiffies = jiffies;
	115
	116	return 0;
	117	}
	118
	119	static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
	120	{
	121	wdd->timeout = t;
	122
	123	return gpio_wdt_ping(wdd);
	124	}
	125
25134eaf AS	126	static const struct watchdog_info gpio_wdt_ident = {
	127	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \|
	128	WDIOF_SETTIMEOUT,
	129	.identity = "GPIO Watchdog",
	130	};
	131
	132	static const struct watchdog_ops gpio_wdt_ops = {
	133	.owner = THIS_MODULE,
	134	.start = gpio_wdt_start,
	135	.stop = gpio_wdt_stop,
	136	.ping = gpio_wdt_ping,
	137	.set_timeout = gpio_wdt_set_timeout,
	138	};
	139
	140	static int gpio_wdt_probe(struct platform_device *pdev)
	141	{
	142	struct gpio_wdt_priv *priv;
	143	enum of_gpio_flags flags;
	144	unsigned int hw_margin;
	145	unsigned long f = 0;
	146	const char *algo;
	147	int ret;
	148
	149	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	150	if (!priv)
	151	return -ENOMEM;
	152
	153	priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
	154	if (!gpio_is_valid(priv->gpio))
	155	return priv->gpio;
	156
	157	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;
	158
	159	ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo);
	160	if (ret)
	161	return ret;
0a0a542f	162	if (!strcmp(algo, "toggle")) {
25134eaf AS	163	priv->hw_algo = HW_ALGO_TOGGLE;
25134eaf AS	164	f = GPIOF_IN;
0a0a542f	165	} else if (!strcmp(algo, "level")) {
25134eaf AS	166	priv->hw_algo = HW_ALGO_LEVEL;
	167	f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
	168	} else {
	169	return -EINVAL;
	170	}
	171
	172	ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f,
	173	dev_name(&pdev->dev));
	174	if (ret)
	175	return ret;
	176
	177	ret = of_property_read_u32(pdev->dev.of_node,
	178	"hw_margin_ms", &hw_margin);
	179	if (ret)
	180	return ret;
	181	/* Disallow values lower than 2 and higher than 65535 ms */
	182	if (hw_margin < 2 \|\| hw_margin > 65535)
	183	return -EINVAL;
	184
	185	/* Use safe value (1/2 of real timeout) */
	186	priv->hw_margin = msecs_to_jiffies(hw_margin / 2);
	187
ba804a95 ML	188	priv->always_running = of_property_read_bool(pdev->dev.of_node,
	189	"always-running");
	190
25134eaf AS	191	watchdog_set_drvdata(&priv->wdd, priv);
	192
	193	priv->wdd.info = &gpio_wdt_ident;
	194	priv->wdd.ops = &gpio_wdt_ops;
	195	priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
	196	priv->wdd.max_timeout = SOFT_TIMEOUT_MAX;
6551881c	197	priv->wdd.parent = &pdev->dev;
25134eaf AS	198
	199	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
	200	priv->wdd.timeout = SOFT_TIMEOUT_DEF;
	201
	202	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);
	203
28e805b4 DR	204	watchdog_stop_on_reboot(&priv->wdd);
28e805b4 DR	205
25134eaf AS	206	ret = watchdog_register_device(&priv->wdd);
	207	if (ret)
	208	return ret;
	209
ba804a95 ML	210	if (priv->always_running)
	211	gpio_wdt_start_impl(priv);
	212
	213	return 0;
25134eaf AS	214	}
	215
	216	static int gpio_wdt_remove(struct platform_device *pdev)
	217	{
	218	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
	219
	220	del_timer_sync(&priv->timer);
25134eaf AS	221	watchdog_unregister_device(&priv->wdd);
	222
	223	return 0;
	224	}
	225
	226	static const struct of_device_id gpio_wdt_dt_ids[] = {
	227	{ .compatible = "linux,wdt-gpio", },
	228	{ }
	229	};
	230	MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
	231
	232	static struct platform_driver gpio_wdt_driver = {
	233	.driver = {
	234	.name = "gpio-wdt",
25134eaf AS	235	.of_match_table = gpio_wdt_dt_ids,
	236	},
	237	.probe = gpio_wdt_probe,
	238	.remove = gpio_wdt_remove,
	239	};
5e53c8ed JBT	240
	241	#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
	242	static int __init gpio_wdt_init(void)
	243	{
	244	return platform_driver_register(&gpio_wdt_driver);
	245	}
	246	arch_initcall(gpio_wdt_init);
	247	#else
25134eaf	248	module_platform_driver(gpio_wdt_driver);
5e53c8ed	249	#endif
25134eaf AS	250
	251	MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
	252	MODULE_DESCRIPTION("GPIO Watchdog");
	253	MODULE_LICENSE("GPL");