drivers/watchdog/da9062_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Watchdog device driver for DA9062 and DA9061 PMICs
   4  * Copyright (C) 2015  Dialog Semiconductor Ltd.
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/watchdog.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/slab.h>
  14 #include <linux/delay.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/mfd/da9062/registers.h>
  17 #include <linux/mfd/da9062/core.h>
  18 #include <linux/regmap.h>
  19 #include <linux/of.h>
  20
  21 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  22 #define DA9062_TWDSCALE_DISABLE         0
  23 #define DA9062_TWDSCALE_MIN             1
  24 #define DA9062_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  25 #define DA9062_WDT_MIN_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MIN]
  26 #define DA9062_WDT_MAX_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MAX]
  27 #define DA9062_WDG_DEFAULT_TIMEOUT      wdt_timeout[DA9062_TWDSCALE_MAX-1]
  28 #define DA9062_RESET_PROTECTION_MS      300
  29
  30 struct da9062_watchdog {
  31         struct da9062 *hw;
  32         struct watchdog_device wdtdev;
  33 };
  34
  35 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
  36 {
  37         unsigned int i;
  38
  39         for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
  40                 if (wdt_timeout[i] >= secs)
  41                         return i;
  42         }
  43
  44         return DA9062_TWDSCALE_MAX;
  45 }
  46
  47 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
  48 {
  49         int ret;
  50
  51         ret = regmap_update_bits(wdt->hw->regmap,
  52                            DA9062AA_CONTROL_F,
  53                            DA9062AA_WATCHDOG_MASK,
  54                            DA9062AA_WATCHDOG_MASK);
  55
  56         return ret;
  57 }
  58
  59 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
  60                                               unsigned int regval)
  61 {
  62         struct da9062 *chip = wdt->hw;
  63         int ret;
  64
  65         ret = da9062_reset_watchdog_timer(wdt);
  66         if (ret)
  67                 return ret;
  68
  69         regmap_update_bits(chip->regmap,
  70                                   DA9062AA_CONTROL_D,
  71                                   DA9062AA_TWDSCALE_MASK,
  72                                   DA9062_TWDSCALE_DISABLE);
  73
  74         usleep_range(150, 300);
  75
  76         return regmap_update_bits(chip->regmap,
  77                                   DA9062AA_CONTROL_D,
  78                                   DA9062AA_TWDSCALE_MASK,
  79                                   regval);
  80 }
  81
  82 static int da9062_wdt_start(struct watchdog_device *wdd)
  83 {
  84         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
  85         unsigned int selector;
  86         int ret;
  87
  88         selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  89         ret = da9062_wdt_update_timeout_register(wdt, selector);
  90         if (ret)
  91                 dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
  92                         ret);
  93
  94         return ret;
  95 }
  96
  97 static int da9062_wdt_stop(struct watchdog_device *wdd)
  98 {
  99         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 100         int ret;
 101
 102         ret = da9062_reset_watchdog_timer(wdt);
 103         if (ret) {
 104                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 105                         ret);
 106                 return ret;
 107         }
 108
 109         ret = regmap_update_bits(wdt->hw->regmap,
 110                                  DA9062AA_CONTROL_D,
 111                                  DA9062AA_TWDSCALE_MASK,
 112                                  DA9062_TWDSCALE_DISABLE);
 113         if (ret)
 114                 dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
 115                         ret);
 116
 117         return ret;
 118 }
 119
 120 static int da9062_wdt_ping(struct watchdog_device *wdd)
 121 {
 122         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 123         int ret;
 124
 125         ret = da9062_reset_watchdog_timer(wdt);
 126         if (ret)
 127                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 128                         ret);
 129
 130         return ret;
 131 }
 132
 133 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
 134                                   unsigned int timeout)
 135 {
 136         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 137         unsigned int selector;
 138         int ret;
 139
 140         selector = da9062_wdt_timeout_to_sel(timeout);
 141         ret = da9062_wdt_update_timeout_register(wdt, selector);
 142         if (ret)
 143                 dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
 144                         ret);
 145         else
 146                 wdd->timeout = wdt_timeout[selector];
 147
 148         return ret;
 149 }
 150
 151 static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 152                               void *data)
 153 {
 154         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 155         int ret;
 156
 157         ret = regmap_write(wdt->hw->regmap,
 158                            DA9062AA_CONTROL_F,
 159                            DA9062AA_SHUTDOWN_MASK);
 160         if (ret)
 161                 dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
 162                           ret);
 163
 164         /* wait for reset to assert... */
 165         mdelay(500);
 166
 167         return ret;
 168 }
 169
 170 static const struct watchdog_info da9062_watchdog_info = {
 171         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 172         .identity = "DA9062 WDT",
 173 };
 174
 175 static const struct watchdog_ops da9062_watchdog_ops = {
 176         .owner = THIS_MODULE,
 177         .start = da9062_wdt_start,
 178         .stop = da9062_wdt_stop,
 179         .ping = da9062_wdt_ping,
 180         .set_timeout = da9062_wdt_set_timeout,
 181         .restart = da9062_wdt_restart,
 182 };
 183
 184 static const struct of_device_id da9062_compatible_id_table[] = {
 185         { .compatible = "dlg,da9062-watchdog", },
 186         { },
 187 };
 188
 189 MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
 190
 191 static int da9062_wdt_probe(struct platform_device *pdev)
 192 {
 193         int ret;
 194         struct da9062 *chip;
 195         struct da9062_watchdog *wdt;
 196
 197         chip = dev_get_drvdata(pdev->dev.parent);
 198         if (!chip)
 199                 return -EINVAL;
 200
 201         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 202         if (!wdt)
 203                 return -ENOMEM;
 204
 205         wdt->hw = chip;
 206
 207         wdt->wdtdev.info = &da9062_watchdog_info;
 208         wdt->wdtdev.ops = &da9062_watchdog_ops;
 209         wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
 210         wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
 211         wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
 212         wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
 213         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 214         wdt->wdtdev.parent = &pdev->dev;
 215
 216         watchdog_set_restart_priority(&wdt->wdtdev, 128);
 217
 218         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 219
 220         ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
 221         if (ret < 0) {
 222                 dev_err(wdt->hw->dev,
 223                         "watchdog registration failed (%d)\n", ret);
 224                 return ret;
 225         }
 226
 227         return da9062_wdt_ping(&wdt->wdtdev);
 228 }
 229
 230 static struct platform_driver da9062_wdt_driver = {
 231         .probe = da9062_wdt_probe,
 232         .driver = {
 233                 .name = "da9062-watchdog",
 234                 .of_match_table = da9062_compatible_id_table,
 235         },
 236 };
 237 module_platform_driver(da9062_wdt_driver);
 238
 239 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
 240 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
 241 MODULE_LICENSE("GPL");
 242 MODULE_ALIAS("platform:da9062-watchdog");