drivers/watchdog/stmp3xxx_rtc_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
   4  *
   5  * Author: Wolfram Sang <kernel@pengutronix.de>
   6  *
   7  * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
   8  */
   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 19
  19 #define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
  20
  21 static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
  22 module_param(heartbeat, uint, 0);
  23 MODULE_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
  27 static 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
  36 static 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
  45 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
  46 {
  47         wdd->timeout = new_timeout;
  48         return wdt_start(wdd);
  49 }
  50
  51 static const struct watchdog_info stmp3xxx_wdt_ident = {
  52         .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  53         .identity = "STMP3XXX RTC Watchdog",
  54 };
  55
  56 static 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
  63 static 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
  71 static 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
  86 static struct notifier_block wdt_notifier = {
  87         .notifier_call = wdt_notify_sys,
  88 };
  89
  90 static 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
 112 static int stmp3xxx_wdt_remove(struct platform_device *pdev)
 113 {
 114         unregister_reboot_notifier(&wdt_notifier);
 115         return 0;
 116 }
 117
 118 static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
 119 {
 120         struct watchdog_device *wdd = &stmp3xxx_wdd;
 121
 122         if (watchdog_active(wdd))
 123                 return wdt_stop(wdd);
 124
 125         return 0;
 126 }
 127
 128 static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
 129 {
 130         struct watchdog_device *wdd = &stmp3xxx_wdd;
 131
 132         if (watchdog_active(wdd))
 133                 return wdt_start(wdd);
 134
 135         return 0;
 136 }
 137
 138 static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
 139                          stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
 140
 141 static struct platform_driver stmp3xxx_wdt_driver = {
 142         .driver = {
 143                 .name = "stmp3xxx_rtc_wdt",
 144                 .pm = &stmp3xxx_wdt_pm_ops,
 145         },
 146         .probe = stmp3xxx_wdt_probe,
 147         .remove = stmp3xxx_wdt_remove,
 148 };
 149 module_platform_driver(stmp3xxx_wdt_driver);
 150
 151 MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
 152 MODULE_LICENSE("GPL v2");
 153 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");