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