1 /* 2 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28 3 * 4 * Author: Wolfram Sang <kernel@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 #include <linux/notifier.h> 18 #include <linux/reboot.h> 19 20 #define WDOG_TICK_RATE 1000 /* 1 kHz clock */ 21 #define STMP3XXX_DEFAULT_TIMEOUT 19 22 #define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE) 23 24 static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT; 25 module_param(heartbeat, uint, 0); 26 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to " 27 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default " 28 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT)); 29 30 static int wdt_start(struct watchdog_device *wdd) 31 { 32 struct device *dev = watchdog_get_drvdata(wdd); 33 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev); 34 35 pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE); 36 return 0; 37 } 38 39 static int wdt_stop(struct watchdog_device *wdd) 40 { 41 struct device *dev = watchdog_get_drvdata(wdd); 42 struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev); 43 44 pdata->wdt_set_timeout(dev->parent, 0); 45 return 0; 46 } 47 48 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout) 49 { 50 wdd->timeout = new_timeout; 51 return wdt_start(wdd); 52 } 53 54 static const struct watchdog_info stmp3xxx_wdt_ident = { 55 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 56 .identity = "STMP3XXX RTC Watchdog", 57 }; 58 59 static const struct watchdog_ops stmp3xxx_wdt_ops = { 60 .owner = THIS_MODULE, 61 .start = wdt_start, 62 .stop = wdt_stop, 63 .set_timeout = wdt_set_timeout, 64 }; 65 66 static struct watchdog_device stmp3xxx_wdd = { 67 .info = &stmp3xxx_wdt_ident, 68 .ops = &stmp3xxx_wdt_ops, 69 .min_timeout = 1, 70 .max_timeout = STMP3XXX_MAX_TIMEOUT, 71 .status = WATCHDOG_NOWAYOUT_INIT_STATUS, 72 }; 73 74 static int wdt_notify_sys(struct notifier_block *nb, unsigned long code, 75 void *unused) 76 { 77 switch (code) { 78 case SYS_DOWN: /* keep enabled, system might crash while going down */ 79 break; 80 case SYS_HALT: /* allow the system to actually halt */ 81 case SYS_POWER_OFF: 82 wdt_stop(&stmp3xxx_wdd); 83 break; 84 } 85 86 return NOTIFY_DONE; 87 } 88 89 static struct notifier_block wdt_notifier = { 90 .notifier_call = wdt_notify_sys, 91 }; 92 93 static int stmp3xxx_wdt_probe(struct platform_device *pdev) 94 { 95 int ret; 96 97 watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev); 98 99 stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT); 100 stmp3xxx_wdd.parent = &pdev->dev; 101 102 ret = watchdog_register_device(&stmp3xxx_wdd); 103 if (ret < 0) { 104 dev_err(&pdev->dev, "cannot register watchdog device\n"); 105 return ret; 106 } 107 108 if (register_reboot_notifier(&wdt_notifier)) 109 dev_warn(&pdev->dev, "cannot register reboot notifier\n"); 110 111 dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n", 112 stmp3xxx_wdd.timeout); 113 return 0; 114 } 115 116 static int stmp3xxx_wdt_remove(struct platform_device *pdev) 117 { 118 unregister_reboot_notifier(&wdt_notifier); 119 watchdog_unregister_device(&stmp3xxx_wdd); 120 return 0; 121 } 122 123 static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev) 124 { 125 struct watchdog_device *wdd = &stmp3xxx_wdd; 126 127 if (watchdog_active(wdd)) 128 return wdt_stop(wdd); 129 130 return 0; 131 } 132 133 static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev) 134 { 135 struct watchdog_device *wdd = &stmp3xxx_wdd; 136 137 if (watchdog_active(wdd)) 138 return wdt_start(wdd); 139 140 return 0; 141 } 142 143 static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops, 144 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume); 145 146 static struct platform_driver stmp3xxx_wdt_driver = { 147 .driver = { 148 .name = "stmp3xxx_rtc_wdt", 149 .pm = &stmp3xxx_wdt_pm_ops, 150 }, 151 .probe = stmp3xxx_wdt_probe, 152 .remove = stmp3xxx_wdt_remove, 153 }; 154 module_platform_driver(stmp3xxx_wdt_driver); 155 156 MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver"); 157 MODULE_LICENSE("GPL v2"); 158 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>"); 159