[deliverable/linux.git] / drivers / watchdog / stmp3xxx_rtc_wdt.c

/*
 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
 *
 * Author: Wolfram Sang <kernel@pengutronix.de>
 *
 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/stmp3xxx_rtc_wdt.h>
#include <linux/notifier.h>
#include <linux/reboot.h>

#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
#define STMP3XXX_DEFAULT_TIMEOUT 19
#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)

static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
		 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
		 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));

static int wdt_start(struct watchdog_device *wdd)
{
	struct device *dev = watchdog_get_drvdata(wdd);
	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);

	pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
	return 0;
}

static int wdt_stop(struct watchdog_device *wdd)
{
	struct device *dev = watchdog_get_drvdata(wdd);
	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);

	pdata->wdt_set_timeout(dev->parent, 0);
	return 0;
}

static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
{
	wdd->timeout = new_timeout;
	return wdt_start(wdd);
}

static const struct watchdog_info stmp3xxx_wdt_ident = {
	.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	.identity = "STMP3XXX RTC Watchdog",
};

static const struct watchdog_ops stmp3xxx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdt_start,
	.stop = wdt_stop,
	.set_timeout = wdt_set_timeout,
};

static struct watchdog_device stmp3xxx_wdd = {
	.info = &stmp3xxx_wdt_ident,
	.ops = &stmp3xxx_wdt_ops,
	.min_timeout = 1,
	.max_timeout = STMP3XXX_MAX_TIMEOUT,
	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
};

static int wdt_notify_sys(struct notifier_block *nb, unsigned long code,
			  void *unused)
{
	switch (code) {
	case SYS_DOWN:	/* keep enabled, system might crash while going down */
		break;
	case SYS_HALT:	/* allow the system to actually halt */
	case SYS_POWER_OFF:
		wdt_stop(&stmp3xxx_wdd);
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static int stmp3xxx_wdt_probe(struct platform_device *pdev)
{
	int ret;

	watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);

	stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
	stmp3xxx_wdd.parent = &pdev->dev;

	ret = watchdog_register_device(&stmp3xxx_wdd);
	if (ret < 0) {
		dev_err(&pdev->dev, "cannot register watchdog device\n");
		return ret;
	}

	if (register_reboot_notifier(&wdt_notifier))
		dev_warn(&pdev->dev, "cannot register reboot notifier\n");

	dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
			stmp3xxx_wdd.timeout);
	return 0;
}

static int stmp3xxx_wdt_remove(struct platform_device *pdev)
{
	unregister_reboot_notifier(&wdt_notifier);
	watchdog_unregister_device(&stmp3xxx_wdd);
	return 0;
}

static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
{
	struct watchdog_device *wdd = &stmp3xxx_wdd;

	if (watchdog_active(wdd))
		return wdt_stop(wdd);

	return 0;
}

static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
{
	struct watchdog_device *wdd = &stmp3xxx_wdd;

	if (watchdog_active(wdd))
		return wdt_start(wdd);

	return 0;
}

static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
			 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);

static struct platform_driver stmp3xxx_wdt_driver = {
	.driver = {
		.name = "stmp3xxx_rtc_wdt",
		.pm = &stmp3xxx_wdt_pm_ops,
	},
	.probe = stmp3xxx_wdt_probe,
	.remove = stmp3xxx_wdt_remove,
};
module_platform_driver(stmp3xxx_wdt_driver);

MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
Commit	Line	Data
de6303ab WS	1	/*
	2	* Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
	3	*
cf82f52d	4	* Author: Wolfram Sang <kernel@pengutronix.de>
de6303ab WS	5	*
	6	* Copyright (C) 2011-12 Wolfram Sang, Pengutronix
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License version 2 as published by
	10	* the Free Software Foundation.
	11	*/
de6303ab WS	12	#include <linux/kernel.h>
de6303ab WS	13	#include <linux/module.h>
de6303ab WS	14	#include <linux/watchdog.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/stmp3xxx_rtc_wdt.h>
8d2fa171 HG	17	#include <linux/notifier.h>
8d2fa171 HG	18	#include <linux/reboot.h>
de6303ab WS	19
	20	#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
	21	#define STMP3XXX_DEFAULT_TIMEOUT 19
	22	#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
	23
	24	static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
	25	module_param(heartbeat, uint, 0);
	26	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
	27	__MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
	28	__MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
	29
	30	static int wdt_start(struct watchdog_device *wdd)
	31	{
	32	struct device *dev = watchdog_get_drvdata(wdd);
bc8fdfbe	33	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
de6303ab WS	34
	35	pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
	36	return 0;
	37	}
	38
	39	static int wdt_stop(struct watchdog_device *wdd)
	40	{
	41	struct device *dev = watchdog_get_drvdata(wdd);
bc8fdfbe	42	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
de6303ab WS	43
	44	pdata->wdt_set_timeout(dev->parent, 0);
	45	return 0;
	46	}
	47
	48	static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
	49	{
	50	wdd->timeout = new_timeout;
	51	return wdt_start(wdd);
	52	}
	53
	54	static const struct watchdog_info stmp3xxx_wdt_ident = {
	55	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	56	.identity = "STMP3XXX RTC Watchdog",
	57	};
	58
	59	static const struct watchdog_ops stmp3xxx_wdt_ops = {
	60	.owner = THIS_MODULE,
	61	.start = wdt_start,
	62	.stop = wdt_stop,
	63	.set_timeout = wdt_set_timeout,
	64	};
	65
	66	static struct watchdog_device stmp3xxx_wdd = {
	67	.info = &stmp3xxx_wdt_ident,
	68	.ops = &stmp3xxx_wdt_ops,
	69	.min_timeout = 1,
	70	.max_timeout = STMP3XXX_MAX_TIMEOUT,
	71	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
	72	};
	73
8d2fa171 HG	74	static int wdt_notify_sys(struct notifier_block *nb, unsigned long code,
	75	void *unused)
	76	{
8d2fa171 HG	77	switch (code) {
	78	case SYS_DOWN: /* keep enabled, system might crash while going down */
	79	break;
	80	case SYS_HALT: /* allow the system to actually halt */
	81	case SYS_POWER_OFF:
	82	wdt_stop(&stmp3xxx_wdd);
	83	break;
	84	}
	85
	86	return NOTIFY_DONE;
	87	}
	88
	89	static struct notifier_block wdt_notifier = {
	90	.notifier_call = wdt_notify_sys,
	91	};
	92
de6303ab WS	93	static int stmp3xxx_wdt_probe(struct platform_device *pdev)
	94	{
	95	int ret;
	96
	97	watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
	98
	99	stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
6551881c	100	stmp3xxx_wdd.parent = &pdev->dev;
de6303ab WS	101
	102	ret = watchdog_register_device(&stmp3xxx_wdd);
	103	if (ret < 0) {
	104	dev_err(&pdev->dev, "cannot register watchdog device\n");
	105	return ret;
	106	}
	107
8d2fa171 HG	108	if (register_reboot_notifier(&wdt_notifier))
	109	dev_warn(&pdev->dev, "cannot register reboot notifier\n");
	110
de6303ab WS	111	dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
	112	stmp3xxx_wdd.timeout);
	113	return 0;
	114	}
	115
	116	static int stmp3xxx_wdt_remove(struct platform_device *pdev)
	117	{
8d2fa171	118	unregister_reboot_notifier(&wdt_notifier);
de6303ab WS	119	watchdog_unregister_device(&stmp3xxx_wdd);
	120	return 0;
	121	}
	122
3281b85c JU	123	static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
	124	{
	125	struct watchdog_device *wdd = &stmp3xxx_wdd;
	126
	127	if (watchdog_active(wdd))
	128	return wdt_stop(wdd);
	129
	130	return 0;
	131	}
	132
	133	static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
	134	{
	135	struct watchdog_device *wdd = &stmp3xxx_wdd;
	136
	137	if (watchdog_active(wdd))
	138	return wdt_start(wdd);
	139
	140	return 0;
	141	}
	142
	143	static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
	144	stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
	145
de6303ab WS	146	static struct platform_driver stmp3xxx_wdt_driver = {
	147	.driver = {
	148	.name = "stmp3xxx_rtc_wdt",
3281b85c	149	.pm = &stmp3xxx_wdt_pm_ops,
de6303ab WS	150	},
	151	.probe = stmp3xxx_wdt_probe,
	152	.remove = stmp3xxx_wdt_remove,
	153	};
	154	module_platform_driver(stmp3xxx_wdt_driver);
	155
	156	MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
	157	MODULE_LICENSE("GPL v2");
cf82f52d	158	MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");