[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/notifier.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/reboot.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;
	unsigned int		hw_algo;
	unsigned int		hw_margin;
	unsigned long		last_jiffies;
	struct notifier_block	notifier;
	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 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);
	priv->last_jiffies = jiffies;
	mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin);

	return 0;
}

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

	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 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 (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 int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code,
			       void *unused)
{
	struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv,
						  notifier);

	mod_timer(&priv->timer, 0);

	switch (code) {
	case SYS_HALT:
	case SYS_POWER_OFF:
		gpio_wdt_disable(priv);
		break;
	default:
		break;
	}

	return NOTIFY_DONE;
}

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 (!strncmp(algo, "toggle", 6)) {
		priv->hw_algo = HW_ALGO_TOGGLE;
		f = GPIOF_IN;
	} else if (!strncmp(algo, "level", 5)) {
		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);

	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;

	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);

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

	priv->notifier.notifier_call = gpio_wdt_notify_sys;
	ret = register_reboot_notifier(&priv->notifier);
	if (ret)
		watchdog_unregister_device(&priv->wdd);

	return ret;
}

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

	del_timer_sync(&priv->timer);
	unregister_reboot_notifier(&priv->notifier);
	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,
};
module_platform_driver(gpio_wdt_driver);

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>
	15	#include <linux/notifier.h>
	16	#include <linux/of_gpio.h>
	17	#include <linux/platform_device.h>
	18	#include <linux/reboot.h>
	19	#include <linux/watchdog.h>
	20
	21	#define SOFT_TIMEOUT_MIN 1
	22	#define SOFT_TIMEOUT_DEF 60
	23	#define SOFT_TIMEOUT_MAX 0xffff
	24
	25	enum {
	26	HW_ALGO_TOGGLE,
	27	HW_ALGO_LEVEL,
	28	};
	29
	30	struct gpio_wdt_priv {
	31	int gpio;
	32	bool active_low;
	33	bool state;
	34	unsigned int hw_algo;
	35	unsigned int hw_margin;
	36	unsigned long last_jiffies;
	37	struct notifier_block notifier;
	38	struct timer_list timer;
	39	struct watchdog_device wdd;
	40	};
	41
	42	static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
	43	{
	44	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
	45
	46	/* Put GPIO back to tristate */
	47	if (priv->hw_algo == HW_ALGO_TOGGLE)
	48	gpio_direction_input(priv->gpio);
	49	}
	50
	51	static int gpio_wdt_start(struct watchdog_device *wdd)
	52	{
	53	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
	54
	55	priv->state = priv->active_low;
	56	gpio_direction_output(priv->gpio, priv->state);
	57	priv->last_jiffies = jiffies;
	58	mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin);
	59
	60	return 0;
	61	}
	62
	63	static int gpio_wdt_stop(struct watchdog_device *wdd)
	64	{
65	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
66
67	mod_timer(&priv->timer, 0);
68	gpio_wdt_disable(priv);
69
70	return 0;
71	}
72
73	static int gpio_wdt_ping(struct watchdog_device *wdd)
74	{
75	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
76
77	priv->last_jiffies = jiffies;
78
79	return 0;
80	}
81
82	static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
83	{
84	wdd->timeout = t;
85
86	return gpio_wdt_ping(wdd);
87	}
88
89	static void gpio_wdt_hwping(unsigned long data)
90	{
91	struct watchdog_device wdd = (struct watchdog_device )data;
92	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
93
94	if (time_after(jiffies, priv->last_jiffies +
95	msecs_to_jiffies(wdd->timeout * 1000))) {
96	dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n");
97	return;
98	}
99
100	/* Restart timer */
101	mod_timer(&priv->timer, jiffies + priv->hw_margin);
102
103	switch (priv->hw_algo) {
104	case HW_ALGO_TOGGLE:
105	/* Toggle output pin */
106	priv->state = !priv->state;
107	gpio_set_value_cansleep(priv->gpio, priv->state);
108	break;
109	case HW_ALGO_LEVEL:
110	/* Pulse */
111	gpio_set_value_cansleep(priv->gpio, !priv->active_low);
112	udelay(1);
113	gpio_set_value_cansleep(priv->gpio, priv->active_low);
114	break;
115	}
116	}
117
118	static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code,
119	void *unused)
120	{
121	struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv,
122	notifier);
123
124	mod_timer(&priv->timer, 0);
125
126	switch (code) {
127	case SYS_HALT:
128	case SYS_POWER_OFF:
129	gpio_wdt_disable(priv);
130	break;
131	default:
132	break;
133	}
134
135	return NOTIFY_DONE;
136	}
137
138	static const struct watchdog_info gpio_wdt_ident = {
139	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \|
140	WDIOF_SETTIMEOUT,
141	.identity = "GPIO Watchdog",
142	};
143
144	static const struct watchdog_ops gpio_wdt_ops = {
145	.owner = THIS_MODULE,
146	.start = gpio_wdt_start,
147	.stop = gpio_wdt_stop,
148	.ping = gpio_wdt_ping,
149	.set_timeout = gpio_wdt_set_timeout,
150	};
151
152	static int gpio_wdt_probe(struct platform_device *pdev)
153	{
154	struct gpio_wdt_priv *priv;
155	enum of_gpio_flags flags;
156	unsigned int hw_margin;
157	unsigned long f = 0;
158	const char *algo;
159	int ret;
160
161	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
162	if (!priv)
163	return -ENOMEM;
164
165	priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
166	if (!gpio_is_valid(priv->gpio))
167	return priv->gpio;
168
169	priv->active_low = flags & OF_GPIO_ACTIVE_LOW;
170
171	ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo);
172	if (ret)
173	return ret;
174	if (!strncmp(algo, "toggle", 6)) {
175	priv->hw_algo = HW_ALGO_TOGGLE;
176	f = GPIOF_IN;
177	} else if (!strncmp(algo, "level", 5)) {
178	priv->hw_algo = HW_ALGO_LEVEL;
179	f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
180	} else {
181	return -EINVAL;
182	}
183
184	ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f,
185	dev_name(&pdev->dev));
186	if (ret)
187	return ret;
188
189	ret = of_property_read_u32(pdev->dev.of_node,
190	"hw_margin_ms", &hw_margin);
191	if (ret)
192	return ret;
193	/* Disallow values lower than 2 and higher than 65535 ms */
194	if (hw_margin < 2 \|\| hw_margin > 65535)
195	return -EINVAL;
196
197	/* Use safe value (1/2 of real timeout) */
198	priv->hw_margin = msecs_to_jiffies(hw_margin / 2);
199
200	watchdog_set_drvdata(&priv->wdd, priv);
201
202	priv->wdd.info = &gpio_wdt_ident;
203	priv->wdd.ops = &gpio_wdt_ops;
204	priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
205	priv->wdd.max_timeout = SOFT_TIMEOUT_MAX;
206
207	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
208	priv->wdd.timeout = SOFT_TIMEOUT_DEF;
209
210	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);
211
212	ret = watchdog_register_device(&priv->wdd);
213	if (ret)
214	return ret;
215
216	priv->notifier.notifier_call = gpio_wdt_notify_sys;
217	ret = register_reboot_notifier(&priv->notifier);
218	if (ret)
219	watchdog_unregister_device(&priv->wdd);
220
221	return ret;
222	}
223
224	static int gpio_wdt_remove(struct platform_device *pdev)
225	{
226	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
227
228	del_timer_sync(&priv->timer);
229	unregister_reboot_notifier(&priv->notifier);
230	watchdog_unregister_device(&priv->wdd);
231
232	return 0;
233	}
234
235	static const struct of_device_id gpio_wdt_dt_ids[] = {
236	{ .compatible = "linux,wdt-gpio", },
237	{ }
238	};
239	MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
240
241	static struct platform_driver gpio_wdt_driver = {
242	.driver = {
243	.name = "gpio-wdt",
25134eaf AS	244	.of_match_table = gpio_wdt_dt_ids,
	245	},
	246	.probe = gpio_wdt_probe,
	247	.remove = gpio_wdt_remove,
	248	};
	249	module_platform_driver(gpio_wdt_driver);
	250
	251	MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
	252	MODULE_DESCRIPTION("GPIO Watchdog");
	253	MODULE_LICENSE("GPL");