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/*
* Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
*
* Author: Wolfram Sang <w.sang@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/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/stmp3xxx_rtc_wdt.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 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);
ret = watchdog_register_device(&stmp3xxx_wdd);
if (ret < 0) {
dev_err(&pdev->dev, "cannot register watchdog device\n");
return ret;
}
dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
stmp3xxx_wdd.timeout);
return 0;
}
static int stmp3xxx_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&stmp3xxx_wdd);
return 0;
}
static struct platform_driver stmp3xxx_wdt_driver = {
.driver = {
.name = "stmp3xxx_rtc_wdt",
},
.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 <w.sang@pengutronix.de>");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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