1*de6303abSWolfram Sang /* 2*de6303abSWolfram Sang * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28 3*de6303abSWolfram Sang * 4*de6303abSWolfram Sang * Author: Wolfram Sang <w.sang@pengutronix.de> 5*de6303abSWolfram Sang * 6*de6303abSWolfram Sang * Copyright (C) 2011-12 Wolfram Sang, Pengutronix 7*de6303abSWolfram Sang * 8*de6303abSWolfram Sang * This program is free software; you can redistribute it and/or modify it 9*de6303abSWolfram Sang * under the terms of the GNU General Public License version 2 as published by 10*de6303abSWolfram Sang * the Free Software Foundation. 11*de6303abSWolfram Sang */ 12*de6303abSWolfram Sang #include <linux/init.h> 13*de6303abSWolfram Sang #include <linux/kernel.h> 14*de6303abSWolfram Sang #include <linux/module.h> 15*de6303abSWolfram Sang #include <linux/miscdevice.h> 16*de6303abSWolfram Sang #include <linux/watchdog.h> 17*de6303abSWolfram Sang #include <linux/platform_device.h> 18*de6303abSWolfram Sang #include <linux/stmp3xxx_rtc_wdt.h> 19*de6303abSWolfram Sang 20*de6303abSWolfram Sang #define WDOG_TICK_RATE 1000 /* 1 kHz clock */ 21*de6303abSWolfram Sang #define STMP3XXX_DEFAULT_TIMEOUT 19 22*de6303abSWolfram Sang #define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE) 23*de6303abSWolfram Sang 24*de6303abSWolfram Sang static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT; 25*de6303abSWolfram Sang module_param(heartbeat, uint, 0); 26*de6303abSWolfram Sang MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to " 27*de6303abSWolfram Sang __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default " 28*de6303abSWolfram Sang __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT)); 29*de6303abSWolfram Sang 30*de6303abSWolfram Sang static int wdt_start(struct watchdog_device *wdd) 31*de6303abSWolfram Sang { 32*de6303abSWolfram Sang struct device *dev = watchdog_get_drvdata(wdd); 33*de6303abSWolfram Sang struct stmp3xxx_wdt_pdata *pdata = dev->platform_data; 34*de6303abSWolfram Sang 35*de6303abSWolfram Sang pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE); 36*de6303abSWolfram Sang return 0; 37*de6303abSWolfram Sang } 38*de6303abSWolfram Sang 39*de6303abSWolfram Sang static int wdt_stop(struct watchdog_device *wdd) 40*de6303abSWolfram Sang { 41*de6303abSWolfram Sang struct device *dev = watchdog_get_drvdata(wdd); 42*de6303abSWolfram Sang struct stmp3xxx_wdt_pdata *pdata = dev->platform_data; 43*de6303abSWolfram Sang 44*de6303abSWolfram Sang pdata->wdt_set_timeout(dev->parent, 0); 45*de6303abSWolfram Sang return 0; 46*de6303abSWolfram Sang } 47*de6303abSWolfram Sang 48*de6303abSWolfram Sang static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout) 49*de6303abSWolfram Sang { 50*de6303abSWolfram Sang wdd->timeout = new_timeout; 51*de6303abSWolfram Sang return wdt_start(wdd); 52*de6303abSWolfram Sang } 53*de6303abSWolfram Sang 54*de6303abSWolfram Sang static const struct watchdog_info stmp3xxx_wdt_ident = { 55*de6303abSWolfram Sang .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 56*de6303abSWolfram Sang .identity = "STMP3XXX RTC Watchdog", 57*de6303abSWolfram Sang }; 58*de6303abSWolfram Sang 59*de6303abSWolfram Sang static const struct watchdog_ops stmp3xxx_wdt_ops = { 60*de6303abSWolfram Sang .owner = THIS_MODULE, 61*de6303abSWolfram Sang .start = wdt_start, 62*de6303abSWolfram Sang .stop = wdt_stop, 63*de6303abSWolfram Sang .set_timeout = wdt_set_timeout, 64*de6303abSWolfram Sang }; 65*de6303abSWolfram Sang 66*de6303abSWolfram Sang static struct watchdog_device stmp3xxx_wdd = { 67*de6303abSWolfram Sang .info = &stmp3xxx_wdt_ident, 68*de6303abSWolfram Sang .ops = &stmp3xxx_wdt_ops, 69*de6303abSWolfram Sang .min_timeout = 1, 70*de6303abSWolfram Sang .max_timeout = STMP3XXX_MAX_TIMEOUT, 71*de6303abSWolfram Sang .status = WATCHDOG_NOWAYOUT_INIT_STATUS, 72*de6303abSWolfram Sang }; 73*de6303abSWolfram Sang 74*de6303abSWolfram Sang static int stmp3xxx_wdt_probe(struct platform_device *pdev) 75*de6303abSWolfram Sang { 76*de6303abSWolfram Sang int ret; 77*de6303abSWolfram Sang 78*de6303abSWolfram Sang watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev); 79*de6303abSWolfram Sang 80*de6303abSWolfram Sang stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT); 81*de6303abSWolfram Sang 82*de6303abSWolfram Sang ret = watchdog_register_device(&stmp3xxx_wdd); 83*de6303abSWolfram Sang if (ret < 0) { 84*de6303abSWolfram Sang dev_err(&pdev->dev, "cannot register watchdog device\n"); 85*de6303abSWolfram Sang return ret; 86*de6303abSWolfram Sang } 87*de6303abSWolfram Sang 88*de6303abSWolfram Sang dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n", 89*de6303abSWolfram Sang stmp3xxx_wdd.timeout); 90*de6303abSWolfram Sang return 0; 91*de6303abSWolfram Sang } 92*de6303abSWolfram Sang 93*de6303abSWolfram Sang static int stmp3xxx_wdt_remove(struct platform_device *pdev) 94*de6303abSWolfram Sang { 95*de6303abSWolfram Sang watchdog_unregister_device(&stmp3xxx_wdd); 96*de6303abSWolfram Sang return 0; 97*de6303abSWolfram Sang } 98*de6303abSWolfram Sang 99*de6303abSWolfram Sang static struct platform_driver stmp3xxx_wdt_driver = { 100*de6303abSWolfram Sang .driver = { 101*de6303abSWolfram Sang .name = "stmp3xxx_rtc_wdt", 102*de6303abSWolfram Sang }, 103*de6303abSWolfram Sang .probe = stmp3xxx_wdt_probe, 104*de6303abSWolfram Sang .remove = stmp3xxx_wdt_remove, 105*de6303abSWolfram Sang }; 106*de6303abSWolfram Sang module_platform_driver(stmp3xxx_wdt_driver); 107*de6303abSWolfram Sang 108*de6303abSWolfram Sang MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver"); 109*de6303abSWolfram Sang MODULE_LICENSE("GPL v2"); 110*de6303abSWolfram Sang MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>"); 111*de6303abSWolfram Sang MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 112