drivers/watchdog/twl4030_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) Nokia Corporation
   4  *
   5  * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/kernel.h>
  12 #include <linux/watchdog.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/mfd/twl.h>
  15
  16 #define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
  17
  18 static bool nowayout = WATCHDOG_NOWAYOUT;
  19 module_param(nowayout, bool, 0);
  20 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  21         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  22
  23 static int twl4030_wdt_write(unsigned char val)
  24 {
  25         return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
  26                                         TWL4030_WATCHDOG_CFG_REG_OFFS);
  27 }
  28
  29 static int twl4030_wdt_start(struct watchdog_device *wdt)
  30 {
  31         return twl4030_wdt_write(wdt->timeout + 1);
  32 }
  33
  34 static int twl4030_wdt_stop(struct watchdog_device *wdt)
  35 {
  36         return twl4030_wdt_write(0);
  37 }
  38
  39 static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
  40                                    unsigned int timeout)
  41 {
  42         wdt->timeout = timeout;
  43         return 0;
  44 }
  45
  46 static const struct watchdog_info twl4030_wdt_info = {
  47         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
  48         .identity = "TWL4030 Watchdog",
  49 };
  50
  51 static const struct watchdog_ops twl4030_wdt_ops = {
  52         .owner          = THIS_MODULE,
  53         .start          = twl4030_wdt_start,
  54         .stop           = twl4030_wdt_stop,
  55         .set_timeout    = twl4030_wdt_set_timeout,
  56 };
  57
  58 static int twl4030_wdt_probe(struct platform_device *pdev)
  59 {
  60         struct device *dev = &pdev->dev;
  61         struct watchdog_device *wdt;
  62
  63         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
  64         if (!wdt)
  65                 return -ENOMEM;
  66
  67         wdt->info               = &twl4030_wdt_info;
  68         wdt->ops                = &twl4030_wdt_ops;
  69         wdt->status             = 0;
  70         wdt->timeout            = 30;
  71         wdt->min_timeout        = 1;
  72         wdt->max_timeout        = 30;
  73         wdt->parent = dev;
  74
  75         watchdog_set_nowayout(wdt, nowayout);
  76         platform_set_drvdata(pdev, wdt);
  77
  78         twl4030_wdt_stop(wdt);
  79
  80         return devm_watchdog_register_device(dev, wdt);
  81 }
  82
  83 #ifdef CONFIG_PM
  84 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
  85 {
  86         struct watchdog_device *wdt = platform_get_drvdata(pdev);
  87         if (watchdog_active(wdt))
  88                 return twl4030_wdt_stop(wdt);
  89
  90         return 0;
  91 }
  92
  93 static int twl4030_wdt_resume(struct platform_device *pdev)
  94 {
  95         struct watchdog_device *wdt = platform_get_drvdata(pdev);
  96         if (watchdog_active(wdt))
  97                 return twl4030_wdt_start(wdt);
  98
  99         return 0;
 100 }
 101 #else
 102 #define twl4030_wdt_suspend        NULL
 103 #define twl4030_wdt_resume         NULL
 104 #endif
 105
 106 static const struct of_device_id twl_wdt_of_match[] = {
 107         { .compatible = "ti,twl4030-wdt", },
 108         { },
 109 };
 110 MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
 111
 112 static struct platform_driver twl4030_wdt_driver = {
 113         .probe          = twl4030_wdt_probe,
 114         .suspend        = twl4030_wdt_suspend,
 115         .resume         = twl4030_wdt_resume,
 116         .driver         = {
 117                 .name           = "twl4030_wdt",
 118                 .of_match_table = twl_wdt_of_match,
 119         },
 120 };
 121
 122 module_platform_driver(twl4030_wdt_driver);
 123
 124 MODULE_AUTHOR("Nokia Corporation");
 125 MODULE_LICENSE("GPL");
 126 MODULE_ALIAS("platform:twl4030_wdt");
 127