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         unsigned long j_time_stamp;
  34 };
  35
  36 static void da9062_set_window_start(struct da9062_watchdog *wdt)
  37 {
  38         wdt->j_time_stamp = jiffies;
  39 }
  40
  41 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
  42 {
  43         unsigned int i;
  44
  45         for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
  46                 if (wdt_timeout[i] >= secs)
  47                         return i;
  48         }
  49
  50         return DA9062_TWDSCALE_MAX;
  51 }
  52
  53 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
  54 {
  55         int ret;
  56
  57         ret = regmap_update_bits(wdt->hw->regmap,
  58                            DA9062AA_CONTROL_F,
  59                            DA9062AA_WATCHDOG_MASK,
  60                            DA9062AA_WATCHDOG_MASK);
  61
  62         da9062_set_window_start(wdt);
  63
  64         return ret;
  65 }
  66
  67 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
  68                                               unsigned int regval)
  69 {
  70         struct da9062 *chip = wdt->hw;
  71         int ret;
  72
  73         ret = da9062_reset_watchdog_timer(wdt);
  74         if (ret)
  75                 return ret;
  76
  77         regmap_update_bits(chip->regmap,
  78                                   DA9062AA_CONTROL_D,
  79                                   DA9062AA_TWDSCALE_MASK,
  80                                   DA9062_TWDSCALE_DISABLE);
  81
  82         usleep_range(150, 300);
  83
  84         return regmap_update_bits(chip->regmap,
  85                                   DA9062AA_CONTROL_D,
  86                                   DA9062AA_TWDSCALE_MASK,
  87                                   regval);
  88 }
  89
  90 static int da9062_wdt_start(struct watchdog_device *wdd)
  91 {
  92         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
  93         unsigned int selector;
  94         int ret;
  95
  96         selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  97         ret = da9062_wdt_update_timeout_register(wdt, selector);
  98         if (ret)
  99                 dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
 100                         ret);
 101
 102         return ret;
 103 }
 104
 105 static int da9062_wdt_stop(struct watchdog_device *wdd)
 106 {
 107         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 108         int ret;
 109
 110         ret = da9062_reset_watchdog_timer(wdt);
 111         if (ret) {
 112                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 113                         ret);
 114                 return ret;
 115         }
 116
 117         ret = regmap_update_bits(wdt->hw->regmap,
 118                                  DA9062AA_CONTROL_D,
 119                                  DA9062AA_TWDSCALE_MASK,
 120                                  DA9062_TWDSCALE_DISABLE);
 121         if (ret)
 122                 dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
 123                         ret);
 124
 125         return ret;
 126 }
 127
 128 static int da9062_wdt_ping(struct watchdog_device *wdd)
 129 {
 130         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 131         int ret;
 132
 133         ret = da9062_reset_watchdog_timer(wdt);
 134         if (ret)
 135                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 136                         ret);
 137
 138         return ret;
 139 }
 140
 141 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
 142                                   unsigned int timeout)
 143 {
 144         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 145         unsigned int selector;
 146         int ret;
 147
 148         selector = da9062_wdt_timeout_to_sel(timeout);
 149         ret = da9062_wdt_update_timeout_register(wdt, selector);
 150         if (ret)
 151                 dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
 152                         ret);
 153         else
 154                 wdd->timeout = wdt_timeout[selector];
 155
 156         return ret;
 157 }
 158
 159 static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 160                               void *data)
 161 {
 162         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 163         int ret;
 164
 165         ret = regmap_write(wdt->hw->regmap,
 166                            DA9062AA_CONTROL_F,
 167                            DA9062AA_SHUTDOWN_MASK);
 168         if (ret)
 169                 dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
 170                           ret);
 171
 172         /* wait for reset to assert... */
 173         mdelay(500);
 174
 175         return ret;
 176 }
 177
 178 static const struct watchdog_info da9062_watchdog_info = {
 179         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 180         .identity = "DA9062 WDT",
 181 };
 182
 183 static const struct watchdog_ops da9062_watchdog_ops = {
 184         .owner = THIS_MODULE,
 185         .start = da9062_wdt_start,
 186         .stop = da9062_wdt_stop,
 187         .ping = da9062_wdt_ping,
 188         .set_timeout = da9062_wdt_set_timeout,
 189         .restart = da9062_wdt_restart,
 190 };
 191
 192 static const struct of_device_id da9062_compatible_id_table[] = {
 193         { .compatible = "dlg,da9062-watchdog", },
 194         { },
 195 };
 196
 197 MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
 198
 199 static int da9062_wdt_probe(struct platform_device *pdev)
 200 {
 201         int ret;
 202         struct da9062 *chip;
 203         struct da9062_watchdog *wdt;
 204
 205         chip = dev_get_drvdata(pdev->dev.parent);
 206         if (!chip)
 207                 return -EINVAL;
 208
 209         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 210         if (!wdt)
 211                 return -ENOMEM;
 212
 213         wdt->hw = chip;
 214
 215         wdt->wdtdev.info = &da9062_watchdog_info;
 216         wdt->wdtdev.ops = &da9062_watchdog_ops;
 217         wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
 218         wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
 219         wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
 220         wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
 221         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 222         wdt->wdtdev.parent = &pdev->dev;
 223
 224         watchdog_set_restart_priority(&wdt->wdtdev, 128);
 225
 226         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 227
 228         ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
 229         if (ret < 0) {
 230                 dev_err(wdt->hw->dev,
 231                         "watchdog registration failed (%d)\n", ret);
 232                 return ret;
 233         }
 234
 235         da9062_set_window_start(wdt);
 236
 237         return da9062_wdt_ping(&wdt->wdtdev);
 238 }
 239
 240 static struct platform_driver da9062_wdt_driver = {
 241         .probe = da9062_wdt_probe,
 242         .driver = {
 243                 .name = "da9062-watchdog",
 244                 .of_match_table = da9062_compatible_id_table,
 245         },
 246 };
 247 module_platform_driver(da9062_wdt_driver);
 248
 249 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
 250 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
 251 MODULE_LICENSE("GPL");
 252 MODULE_ALIAS("platform:da9062-watchdog");