LXR linux/drivers/watchdog/stmp3xxx_rtc

   1/*
   2 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
   3 *
   4 * Author: Wolfram Sang <w.sang@pengutronix.de>
   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 */
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/watchdog.h>
  15#include <linux/platform_device.h>
  16#include <linux/stmp3xxx_rtc_wdt.h>
  17
  18#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
  19#define STMP3XXX_DEFAULT_TIMEOUT 19
  20#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
  21
  22static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
  23module_param(heartbeat, uint, 0);
  24MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
  25                 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
  26                 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
  27
  28static int wdt_start(struct watchdog_device *wdd)
  29{
  30        struct device *dev = watchdog_get_drvdata(wdd);
  31        struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
  32
  33        pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
  34        return 0;
  35}
  36
  37static int wdt_stop(struct watchdog_device *wdd)
  38{
  39        struct device *dev = watchdog_get_drvdata(wdd);
  40        struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
  41
  42        pdata->wdt_set_timeout(dev->parent, 0);
  43        return 0;
  44}
  45
  46static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
  47{
  48        wdd->timeout = new_timeout;
  49        return wdt_start(wdd);
  50}
  51
  52static const struct watchdog_info stmp3xxx_wdt_ident = {
  53        .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  54        .identity = "STMP3XXX RTC Watchdog",
  55};
  56
  57static const struct watchdog_ops stmp3xxx_wdt_ops = {
  58        .owner = THIS_MODULE,
  59        .start = wdt_start,
  60        .stop = wdt_stop,
  61        .set_timeout = wdt_set_timeout,
  62};
  63
  64static struct watchdog_device stmp3xxx_wdd = {
  65        .info = &stmp3xxx_wdt_ident,
  66        .ops = &stmp3xxx_wdt_ops,
  67        .min_timeout = 1,
  68        .max_timeout = STMP3XXX_MAX_TIMEOUT,
  69        .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
  70};
  71
  72static int stmp3xxx_wdt_probe(struct platform_device *pdev)
  73{
  74        int ret;
  75
  76        watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
  77
  78        stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
  79
  80        ret = watchdog_register_device(&stmp3xxx_wdd);
  81        if (ret < 0) {
  82                dev_err(&pdev->dev, "cannot register watchdog device\n");
  83                return ret;
  84        }
  85
  86        dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
  87                        stmp3xxx_wdd.timeout);
  88        return 0;
  89}
  90
  91static int stmp3xxx_wdt_remove(struct platform_device *pdev)
  92{
  93        watchdog_unregister_device(&stmp3xxx_wdd);
  94        return 0;
  95}
  96
  97static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
  98{
  99        struct watchdog_device *wdd = &stmp3xxx_wdd;
 100
 101        if (watchdog_active(wdd))
 102                return wdt_stop(wdd);
 103
 104        return 0;
 105}
 106
 107static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
 108{
 109        struct watchdog_device *wdd = &stmp3xxx_wdd;
 110
 111        if (watchdog_active(wdd))
 112                return wdt_start(wdd);
 113
 114        return 0;
 115}
 116
 117static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
 118                         stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
 119
 120static struct platform_driver stmp3xxx_wdt_driver = {
 121        .driver = {
 122                .name = "stmp3xxx_rtc_wdt",
 123                .pm = &stmp3xxx_wdt_pm_ops,
 124        },
 125        .probe = stmp3xxx_wdt_probe,
 126        .remove = stmp3xxx_wdt_remove,
 127};
 128module_platform_driver(stmp3xxx_wdt_driver);
 129
 130MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
 131MODULE_LICENSE("GPL v2");
 132MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
 133