drivers/watchdog/da9055_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * System monitoring driver for DA9055 PMICs.
   4  *
   5  * Copyright(c) 2012 Dialog Semiconductor Ltd.
   6  *
   7  * Author: David Dajun Chen <dchen@diasemi.com>
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/watchdog.h>
  17 #include <linux/delay.h>
  18
  19 #include <linux/mfd/da9055/core.h>
  20 #include <linux/mfd/da9055/reg.h>
  21
  22 static bool nowayout = WATCHDOG_NOWAYOUT;
  23 module_param(nowayout, bool, 0);
  24 MODULE_PARM_DESC(nowayout,
  25                  "Watchdog cannot be stopped once started (default="
  26                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  27
  28 #define DA9055_DEF_TIMEOUT      4
  29 #define DA9055_TWDMIN           256
  30
  31 struct da9055_wdt_data {
  32         struct watchdog_device wdt;
  33         struct da9055 *da9055;
  34 };
  35
  36 static const struct {
  37         u8 reg_val;
  38         int user_time;  /* In seconds */
  39 } da9055_wdt_maps[] = {
  40         { 0, 0 },
  41         { 1, 2 },
  42         { 2, 4 },
  43         { 3, 8 },
  44         { 4, 16 },
  45         { 5, 32 },
  46         { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
  47         { 6, 65 },
  48         { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
  49         { 7, 131 },
  50 };
  51
  52 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
  53                                   unsigned int timeout)
  54 {
  55         struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  56         struct da9055 *da9055 = driver_data->da9055;
  57         int ret, i;
  58
  59         for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
  60                 if (da9055_wdt_maps[i].user_time == timeout)
  61                         break;
  62
  63         if (i == ARRAY_SIZE(da9055_wdt_maps))
  64                 ret = -EINVAL;
  65         else
  66                 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
  67                                         DA9055_TWDSCALE_MASK,
  68                                         da9055_wdt_maps[i].reg_val <<
  69                                         DA9055_TWDSCALE_SHIFT);
  70         if (ret < 0) {
  71                 dev_err(da9055->dev,
  72                         "Failed to update timescale bit, %d\n", ret);
  73                 return ret;
  74         }
  75
  76         wdt_dev->timeout = timeout;
  77
  78         return 0;
  79 }
  80
  81 static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
  82 {
  83         struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  84         struct da9055 *da9055 = driver_data->da9055;
  85
  86         /*
  87          * We have a minimum time for watchdog window called TWDMIN. A write
  88          * to the watchdog before this elapsed time will cause an error.
  89          */
  90         mdelay(DA9055_TWDMIN);
  91
  92         /* Reset the watchdog timer */
  93         return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
  94                                  DA9055_WATCHDOG_MASK, 1);
  95 }
  96
  97 static int da9055_wdt_start(struct watchdog_device *wdt_dev)
  98 {
  99         return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 100 }
 101
 102 static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
 103 {
 104         return da9055_wdt_set_timeout(wdt_dev, 0);
 105 }
 106
 107 static const struct watchdog_info da9055_wdt_info = {
 108         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 109         .identity       = "DA9055 Watchdog",
 110 };
 111
 112 static const struct watchdog_ops da9055_wdt_ops = {
 113         .owner = THIS_MODULE,
 114         .start = da9055_wdt_start,
 115         .stop = da9055_wdt_stop,
 116         .ping = da9055_wdt_ping,
 117         .set_timeout = da9055_wdt_set_timeout,
 118 };
 119
 120 static int da9055_wdt_probe(struct platform_device *pdev)
 121 {
 122         struct device *dev = &pdev->dev;
 123         struct da9055 *da9055 = dev_get_drvdata(dev->parent);
 124         struct da9055_wdt_data *driver_data;
 125         struct watchdog_device *da9055_wdt;
 126         int ret;
 127
 128         driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
 129         if (!driver_data)
 130                 return -ENOMEM;
 131
 132         driver_data->da9055 = da9055;
 133
 134         da9055_wdt = &driver_data->wdt;
 135
 136         da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
 137         da9055_wdt->info = &da9055_wdt_info;
 138         da9055_wdt->ops = &da9055_wdt_ops;
 139         da9055_wdt->parent = dev;
 140         watchdog_set_nowayout(da9055_wdt, nowayout);
 141         watchdog_set_drvdata(da9055_wdt, driver_data);
 142
 143         ret = da9055_wdt_stop(da9055_wdt);
 144         if (ret < 0) {
 145                 dev_err(dev, "Failed to stop watchdog, %d\n", ret);
 146                 return ret;
 147         }
 148
 149         ret = devm_watchdog_register_device(dev, &driver_data->wdt);
 150         if (ret != 0)
 151                 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
 152                         ret);
 153
 154         return ret;
 155 }
 156
 157 static struct platform_driver da9055_wdt_driver = {
 158         .probe = da9055_wdt_probe,
 159         .driver = {
 160                 .name   = "da9055-watchdog",
 161         },
 162 };
 163
 164 module_platform_driver(da9055_wdt_driver);
 165
 166 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
 167 MODULE_DESCRIPTION("DA9055 watchdog");
 168 MODULE_LICENSE("GPL");
 169 MODULE_ALIAS("platform:da9055-watchdog");