drivers/watchdog/max77620_wdt.c

   1 /*
   2  * Maxim MAX77620 Watchdog Driver
   3  *
   4  * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
   5  *
   6  * Author: Laxman Dewangan <ldewangan@nvidia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/mod_devicetable.h>
  18 #include <linux/mfd/max77620.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21 #include <linux/slab.h>
  22 #include <linux/watchdog.h>
  23
  24 static bool nowayout = WATCHDOG_NOWAYOUT;
  25
  26 struct max77620_wdt {
  27         struct device                   *dev;
  28         struct regmap                   *rmap;
  29         struct watchdog_device          wdt_dev;
  30 };
  31
  32 static int max77620_wdt_start(struct watchdog_device *wdt_dev)
  33 {
  34         struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  35
  36         return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
  37                                   MAX77620_WDTEN, MAX77620_WDTEN);
  38 }
  39
  40 static int max77620_wdt_stop(struct watchdog_device *wdt_dev)
  41 {
  42         struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  43
  44         return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
  45                                   MAX77620_WDTEN, 0);
  46 }
  47
  48 static int max77620_wdt_ping(struct watchdog_device *wdt_dev)
  49 {
  50         struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  51
  52         return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
  53                                   MAX77620_WDTC_MASK, 0x1);
  54 }
  55
  56 static int max77620_wdt_set_timeout(struct watchdog_device *wdt_dev,
  57                                     unsigned int timeout)
  58 {
  59         struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  60         unsigned int wdt_timeout;
  61         u8 regval;
  62         int ret;
  63
  64         switch (timeout) {
  65         case 0 ... 2:
  66                 regval = MAX77620_TWD_2s;
  67                 wdt_timeout = 2;
  68                 break;
  69
  70         case 3 ... 16:
  71                 regval = MAX77620_TWD_16s;
  72                 wdt_timeout = 16;
  73                 break;
  74
  75         case 17 ... 64:
  76                 regval = MAX77620_TWD_64s;
  77                 wdt_timeout = 64;
  78                 break;
  79
  80         default:
  81                 regval = MAX77620_TWD_128s;
  82                 wdt_timeout = 128;
  83                 break;
  84         }
  85
  86         ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
  87                                  MAX77620_WDTC_MASK, 0x1);
  88         if (ret < 0)
  89                 return ret;
  90
  91         ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
  92                                  MAX77620_TWD_MASK, regval);
  93         if (ret < 0)
  94                 return ret;
  95
  96         wdt_dev->timeout = wdt_timeout;
  97
  98         return 0;
  99 }
 100
 101 static const struct watchdog_info max77620_wdt_info = {
 102         .identity = "max77620-watchdog",
 103         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 104 };
 105
 106 static const struct watchdog_ops max77620_wdt_ops = {
 107         .start          = max77620_wdt_start,
 108         .stop           = max77620_wdt_stop,
 109         .ping           = max77620_wdt_ping,
 110         .set_timeout    = max77620_wdt_set_timeout,
 111 };
 112
 113 static int max77620_wdt_probe(struct platform_device *pdev)
 114 {
 115         struct max77620_wdt *wdt;
 116         struct watchdog_device *wdt_dev;
 117         unsigned int regval;
 118         int ret;
 119
 120         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 121         if (!wdt)
 122                 return -ENOMEM;
 123
 124         wdt->dev = &pdev->dev;
 125         wdt->rmap = dev_get_regmap(pdev->dev.parent, NULL);
 126         if (!wdt->rmap) {
 127                 dev_err(wdt->dev, "Failed to get parent regmap\n");
 128                 return -ENODEV;
 129         }
 130
 131         wdt_dev = &wdt->wdt_dev;
 132         wdt_dev->info = &max77620_wdt_info;
 133         wdt_dev->ops = &max77620_wdt_ops;
 134         wdt_dev->min_timeout = 2;
 135         wdt_dev->max_timeout = 128;
 136         wdt_dev->max_hw_heartbeat_ms = 128 * 1000;
 137
 138         platform_set_drvdata(pdev, wdt);
 139
 140         /* Enable WD_RST_WK - WDT expire results in a restart */
 141         ret = regmap_update_bits(wdt->rmap, MAX77620_REG_ONOFFCNFG2,
 142                                  MAX77620_ONOFFCNFG2_WD_RST_WK,
 143                                  MAX77620_ONOFFCNFG2_WD_RST_WK);
 144         if (ret < 0) {
 145                 dev_err(wdt->dev, "Failed to set WD_RST_WK: %d\n", ret);
 146                 return ret;
 147         }
 148
 149         /* Set WDT clear in OFF and sleep mode */
 150         ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
 151                                  MAX77620_WDTOFFC | MAX77620_WDTSLPC,
 152                                  MAX77620_WDTOFFC | MAX77620_WDTSLPC);
 153         if (ret < 0) {
 154                 dev_err(wdt->dev, "Failed to set WDT OFF mode: %d\n", ret);
 155                 return ret;
 156         }
 157
 158         /* Check if WDT running and if yes then set flags properly */
 159         ret = regmap_read(wdt->rmap, MAX77620_REG_CNFGGLBL2, &regval);
 160         if (ret < 0) {
 161                 dev_err(wdt->dev, "Failed to read WDT CFG register: %d\n", ret);
 162                 return ret;
 163         }
 164
 165         switch (regval & MAX77620_TWD_MASK) {
 166         case MAX77620_TWD_2s:
 167                 wdt_dev->timeout = 2;
 168                 break;
 169         case MAX77620_TWD_16s:
 170                 wdt_dev->timeout = 16;
 171                 break;
 172         case MAX77620_TWD_64s:
 173                 wdt_dev->timeout = 64;
 174                 break;
 175         default:
 176                 wdt_dev->timeout = 128;
 177                 break;
 178         }
 179
 180         if (regval & MAX77620_WDTEN)
 181                 set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
 182
 183         watchdog_set_nowayout(wdt_dev, nowayout);
 184         watchdog_set_drvdata(wdt_dev, wdt);
 185
 186         ret = watchdog_register_device(wdt_dev);
 187         if (ret < 0) {
 188                 dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
 189                 return ret;
 190         }
 191
 192         return 0;
 193 }
 194
 195 static int max77620_wdt_remove(struct platform_device *pdev)
 196 {
 197         struct max77620_wdt *wdt = platform_get_drvdata(pdev);
 198
 199         max77620_wdt_stop(&wdt->wdt_dev);
 200         watchdog_unregister_device(&wdt->wdt_dev);
 201
 202         return 0;
 203 }
 204
 205 static const struct platform_device_id max77620_wdt_devtype[] = {
 206         { .name = "max77620-watchdog", },
 207         { },
 208 };
 209 MODULE_DEVICE_TABLE(platform, max77620_wdt_devtype);
 210
 211 static struct platform_driver max77620_wdt_driver = {
 212         .driver = {
 213                 .name   = "max77620-watchdog",
 214         },
 215         .probe  = max77620_wdt_probe,
 216         .remove = max77620_wdt_remove,
 217         .id_table = max77620_wdt_devtype,
 218 };
 219
 220 module_platform_driver(max77620_wdt_driver);
 221
 222 MODULE_DESCRIPTION("Max77620 watchdog timer driver");
 223
 224 module_param(nowayout, bool, 0);
 225 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 226         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 227
 228 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 229 MODULE_LICENSE("GPL v2");