drivers/watchdog/twl4030_wdt.c

   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
  31 static bool nowayout = WATCHDOG_NOWAYOUT;
  32 module_param(nowayout, bool, 0);
  33 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  34         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  35
  36 static 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
  42 static int twl4030_wdt_start(struct watchdog_device *wdt)
  43 {
  44         return twl4030_wdt_write(wdt->timeout + 1);
  45 }
  46
  47 static int twl4030_wdt_stop(struct watchdog_device *wdt)
  48 {
  49         return twl4030_wdt_write(0);
  50 }
  51
  52 static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
  53                                    unsigned int timeout)
  54 {
  55         wdt->timeout = timeout;
  56         return 0;
  57 }
  58
  59 static const struct watchdog_info twl4030_wdt_info = {
  60         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  61         .identity = "TWL4030 Watchdog",
  62 };
  63
  64 static 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
  71 static 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                 return ret;
  95
  96         return 0;
  97 }
  98
  99 static int twl4030_wdt_remove(struct platform_device *pdev)
 100 {
 101         struct watchdog_device *wdt = platform_get_drvdata(pdev);
 102
 103         watchdog_unregister_device(wdt);
 104
 105         return 0;
 106 }
 107
 108 #ifdef CONFIG_PM
 109 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 110 {
 111         struct watchdog_device *wdt = platform_get_drvdata(pdev);
 112         if (watchdog_active(wdt))
 113                 return twl4030_wdt_stop(wdt);
 114
 115         return 0;
 116 }
 117
 118 static int twl4030_wdt_resume(struct platform_device *pdev)
 119 {
 120         struct watchdog_device *wdt = platform_get_drvdata(pdev);
 121         if (watchdog_active(wdt))
 122                 return twl4030_wdt_start(wdt);
 123
 124         return 0;
 125 }
 126 #else
 127 #define twl4030_wdt_suspend        NULL
 128 #define twl4030_wdt_resume         NULL
 129 #endif
 130
 131 static const struct of_device_id twl_wdt_of_match[] = {
 132         { .compatible = "ti,twl4030-wdt", },
 133         { },
 134 };
 135 MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
 136
 137 static struct platform_driver twl4030_wdt_driver = {
 138         .probe          = twl4030_wdt_probe,
 139         .remove         = twl4030_wdt_remove,
 140         .suspend        = twl4030_wdt_suspend,
 141         .resume         = twl4030_wdt_resume,
 142         .driver         = {
 143                 .owner          = THIS_MODULE,
 144                 .name           = "twl4030_wdt",
 145                 .of_match_table = twl_wdt_of_match,
 146         },
 147 };
 148
 149 module_platform_driver(twl4030_wdt_driver);
 150
 151 MODULE_AUTHOR("Nokia Corporation");
 152 MODULE_LICENSE("GPL");
 153 MODULE_ALIAS("platform:twl4030_wdt");
 154