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