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1// SPDX-License-Identifier: GPL-2.02/*3 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/284 *5 * Author: Wolfram Sang <kernel@pengutronix.de>6 *7 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix8 */9#include <linux/kernel.h>10#include <linux/module.h>11#include <linux/watchdog.h>12#include <linux/platform_device.h>13#include <linux/stmp3xxx_rtc_wdt.h>14#include <linux/notifier.h>15#include <linux/reboot.h>16 17#define WDOG_TICK_RATE 1000 /* 1 kHz clock */18#define STMP3XXX_DEFAULT_TIMEOUT 1919#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)20 21static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;22module_param(heartbeat, uint, 0);23MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "24 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "25 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));26 27static int wdt_start(struct watchdog_device *wdd)28{29 struct device *dev = watchdog_get_drvdata(wdd);30 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);31 32 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);33 return 0;34}35 36static int wdt_stop(struct watchdog_device *wdd)37{38 struct device *dev = watchdog_get_drvdata(wdd);39 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);40 41 pdata->wdt_set_timeout(dev->parent, 0);42 return 0;43}44 45static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)46{47 wdd->timeout = new_timeout;48 return wdt_start(wdd);49}50 51static const struct watchdog_info stmp3xxx_wdt_ident = {52 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,53 .identity = "STMP3XXX RTC Watchdog",54};55 56static const struct watchdog_ops stmp3xxx_wdt_ops = {57 .owner = THIS_MODULE,58 .start = wdt_start,59 .stop = wdt_stop,60 .set_timeout = wdt_set_timeout,61};62 63static struct watchdog_device stmp3xxx_wdd = {64 .info = &stmp3xxx_wdt_ident,65 .ops = &stmp3xxx_wdt_ops,66 .min_timeout = 1,67 .max_timeout = STMP3XXX_MAX_TIMEOUT,68 .status = WATCHDOG_NOWAYOUT_INIT_STATUS,69};70 71static int wdt_notify_sys(struct notifier_block *nb, unsigned long code,72 void *unused)73{74 switch (code) {75 case SYS_DOWN: /* keep enabled, system might crash while going down */76 break;77 case SYS_HALT: /* allow the system to actually halt */78 case SYS_POWER_OFF:79 wdt_stop(&stmp3xxx_wdd);80 break;81 }82 83 return NOTIFY_DONE;84}85 86static struct notifier_block wdt_notifier = {87 .notifier_call = wdt_notify_sys,88};89 90static int stmp3xxx_wdt_probe(struct platform_device *pdev)91{92 struct device *dev = &pdev->dev;93 int ret;94 95 watchdog_set_drvdata(&stmp3xxx_wdd, dev);96 97 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);98 stmp3xxx_wdd.parent = dev;99 100 ret = devm_watchdog_register_device(dev, &stmp3xxx_wdd);101 if (ret < 0)102 return ret;103 104 if (register_reboot_notifier(&wdt_notifier))105 dev_warn(dev, "cannot register reboot notifier\n");106 107 dev_info(dev, "initialized watchdog with heartbeat %ds\n",108 stmp3xxx_wdd.timeout);109 return 0;110}111 112static void stmp3xxx_wdt_remove(struct platform_device *pdev)113{114 unregister_reboot_notifier(&wdt_notifier);115}116 117static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)118{119 struct watchdog_device *wdd = &stmp3xxx_wdd;120 121 if (watchdog_active(wdd))122 return wdt_stop(wdd);123 124 return 0;125}126 127static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)128{129 struct watchdog_device *wdd = &stmp3xxx_wdd;130 131 if (watchdog_active(wdd))132 return wdt_start(wdd);133 134 return 0;135}136 137static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,138 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);139 140static struct platform_driver stmp3xxx_wdt_driver = {141 .driver = {142 .name = "stmp3xxx_rtc_wdt",143 .pm = &stmp3xxx_wdt_pm_ops,144 },145 .probe = stmp3xxx_wdt_probe,146 .remove_new = stmp3xxx_wdt_remove,147};148module_platform_driver(stmp3xxx_wdt_driver);149 150MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");151MODULE_LICENSE("GPL v2");152MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");153