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