// SPDX-License-Identifier: GPL-2.0 /* * 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 */ #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>");