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