linux/drivers/watchdog/twl4030_wdt.c
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   1/*
   2 * Copyright (C) Nokia Corporation
   3 *
   4 * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/types.h>
  23#include <linux/slab.h>
  24#include <linux/kernel.h>
  25#include <linux/watchdog.h>
  26#include <linux/platform_device.h>
  27#include <linux/i2c/twl.h>
  28
  29#define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
  30
  31static bool nowayout = WATCHDOG_NOWAYOUT;
  32module_param(nowayout, bool, 0);
  33MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  34        "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  35
  36static int twl4030_wdt_write(unsigned char val)
  37{
  38        return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
  39                                        TWL4030_WATCHDOG_CFG_REG_OFFS);
  40}
  41
  42static int twl4030_wdt_start(struct watchdog_device *wdt)
  43{
  44        return twl4030_wdt_write(wdt->timeout + 1);
  45}
  46
  47static int twl4030_wdt_stop(struct watchdog_device *wdt)
  48{
  49        return twl4030_wdt_write(0);
  50}
  51
  52static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
  53                                   unsigned int timeout)
  54{
  55        wdt->timeout = timeout;
  56        return 0;
  57}
  58
  59static const struct watchdog_info twl4030_wdt_info = {
  60        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  61        .identity = "TWL4030 Watchdog",
  62};
  63
  64static const struct watchdog_ops twl4030_wdt_ops = {
  65        .owner          = THIS_MODULE,
  66        .start          = twl4030_wdt_start,
  67        .stop           = twl4030_wdt_stop,
  68        .set_timeout    = twl4030_wdt_set_timeout,
  69};
  70
  71static int twl4030_wdt_probe(struct platform_device *pdev)
  72{
  73        int ret = 0;
  74        struct watchdog_device *wdt;
  75
  76        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
  77        if (!wdt)
  78                return -ENOMEM;
  79
  80        wdt->info               = &twl4030_wdt_info;
  81        wdt->ops                = &twl4030_wdt_ops;
  82        wdt->status             = 0;
  83        wdt->timeout            = 30;
  84        wdt->min_timeout        = 1;
  85        wdt->max_timeout        = 30;
  86
  87        watchdog_set_nowayout(wdt, nowayout);
  88        platform_set_drvdata(pdev, wdt);
  89
  90        twl4030_wdt_stop(wdt);
  91
  92        ret = watchdog_register_device(wdt);
  93        if (ret) {
  94                platform_set_drvdata(pdev, NULL);
  95                return ret;
  96        }
  97
  98        return 0;
  99}
 100
 101static int twl4030_wdt_remove(struct platform_device *pdev)
 102{
 103        struct watchdog_device *wdt = platform_get_drvdata(pdev);
 104
 105        watchdog_unregister_device(wdt);
 106        platform_set_drvdata(pdev, NULL);
 107
 108        return 0;
 109}
 110
 111#ifdef CONFIG_PM
 112static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 113{
 114        struct watchdog_device *wdt = platform_get_drvdata(pdev);
 115        if (watchdog_active(wdt))
 116                return twl4030_wdt_stop(wdt);
 117
 118        return 0;
 119}
 120
 121static int twl4030_wdt_resume(struct platform_device *pdev)
 122{
 123        struct watchdog_device *wdt = platform_get_drvdata(pdev);
 124        if (watchdog_active(wdt))
 125                return twl4030_wdt_start(wdt);
 126
 127        return 0;
 128}
 129#else
 130#define twl4030_wdt_suspend        NULL
 131#define twl4030_wdt_resume         NULL
 132#endif
 133
 134static const struct of_device_id twl_wdt_of_match[] = {
 135        { .compatible = "ti,twl4030-wdt", },
 136        { },
 137};
 138MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
 139
 140static struct platform_driver twl4030_wdt_driver = {
 141        .probe          = twl4030_wdt_probe,
 142        .remove         = twl4030_wdt_remove,
 143        .suspend        = twl4030_wdt_suspend,
 144        .resume         = twl4030_wdt_resume,
 145        .driver         = {
 146                .owner          = THIS_MODULE,
 147                .name           = "twl4030_wdt",
 148                .of_match_table = twl_wdt_of_match,
 149        },
 150};
 151
 152module_platform_driver(twl4030_wdt_driver);
 153
 154MODULE_AUTHOR("Nokia Corporation");
 155MODULE_LICENSE("GPL");
 156MODULE_ALIAS("platform:twl4030_wdt");
 157
 158
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