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Linux/drivers/watchdog/stmp3xxx_rtc_wdt.c

  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 

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