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/mod_devicetable.h>
  13 #include <linux/watchdog.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/mfd/twl.h>
  16
  17 #define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
  18
  19 static bool nowayout = WATCHDOG_NOWAYOUT;
  20 module_param(nowayout, bool, 0);
  21 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  22         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  23
  24 static int twl4030_wdt_write(unsigned char val)
  25 {
  26         return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
  27                                         TWL4030_WATCHDOG_CFG_REG_OFFS);
  28 }
  29
  30 static int twl4030_wdt_start(struct watchdog_device *wdt)
  31 {
  32         return twl4030_wdt_write(wdt->timeout + 1);
  33 }
  34
  35 static int twl4030_wdt_stop(struct watchdog_device *wdt)
  36 {
  37         return twl4030_wdt_write(0);
  38 }
  39
  40 static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
  41                                    unsigned int timeout)
  42 {
  43         wdt->timeout = timeout;
  44         return 0;
  45 }
  46
  47 static const struct watchdog_info twl4030_wdt_info = {
  48         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
  49         .identity = "TWL4030 Watchdog",
  50 };
  51
  52 static const struct watchdog_ops twl4030_wdt_ops = {
  53         .owner          = THIS_MODULE,
  54         .start          = twl4030_wdt_start,
  55         .stop           = twl4030_wdt_stop,
  56         .set_timeout    = twl4030_wdt_set_timeout,
  57 };
  58
  59 static int twl4030_wdt_probe(struct platform_device *pdev)
  60 {
  61         struct device *dev = &pdev->dev;
  62         struct watchdog_device *wdt;
  63
  64         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
  65         if (!wdt)
  66                 return -ENOMEM;
  67
  68         wdt->info               = &twl4030_wdt_info;
  69         wdt->ops                = &twl4030_wdt_ops;
  70         wdt->status             = 0;
  71         wdt->timeout            = 30;
  72         wdt->min_timeout        = 1;
  73         wdt->max_timeout        = 30;
  74         wdt->parent = dev;
  75
  76         watchdog_set_nowayout(wdt, nowayout);
  77         platform_set_drvdata(pdev, wdt);
  78
  79         twl4030_wdt_stop(wdt);
  80
  81         return devm_watchdog_register_device(dev, wdt);
  82 }
  83
  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
 102 static const struct of_device_id twl_wdt_of_match[] = {
 103         { .compatible = "ti,twl4030-wdt", },
 104         { },
 105 };
 106 MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
 107
 108 static struct platform_driver twl4030_wdt_driver = {
 109         .probe          = twl4030_wdt_probe,
 110         .suspend        = pm_ptr(twl4030_wdt_suspend),
 111         .resume         = pm_ptr(twl4030_wdt_resume),
 112         .driver         = {
 113                 .name           = "twl4030_wdt",
 114                 .of_match_table = twl_wdt_of_match,
 115         },
 116 };
 117
 118 module_platform_driver(twl4030_wdt_driver);
 119
 120 MODULE_AUTHOR("Nokia Corporation");
 121 MODULE_DESCRIPTION("TWL4030 Watchdog");
 122 MODULE_LICENSE("GPL");
 123 MODULE_ALIAS("platform:twl4030_wdt");
 124