drivers/watchdog/da9062_wdt.c

   1 /*
   2  * Watchdog device driver for DA9062 and DA9061 PMICs
   3  * Copyright (C) 2015  Dialog Semiconductor Ltd.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/watchdog.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/mfd/da9062/registers.h>
  25 #include <linux/mfd/da9062/core.h>
  26 #include <linux/regmap.h>
  27 #include <linux/of.h>
  28
  29 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  30 #define DA9062_TWDSCALE_DISABLE         0
  31 #define DA9062_TWDSCALE_MIN             1
  32 #define DA9062_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  33 #define DA9062_WDT_MIN_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MIN]
  34 #define DA9062_WDT_MAX_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MAX]
  35 #define DA9062_WDG_DEFAULT_TIMEOUT      wdt_timeout[DA9062_TWDSCALE_MAX-1]
  36 #define DA9062_RESET_PROTECTION_MS      300
  37
  38 struct da9062_watchdog {
  39         struct da9062 *hw;
  40         struct watchdog_device wdtdev;
  41         unsigned long j_time_stamp;
  42 };
  43
  44 static void da9062_set_window_start(struct da9062_watchdog *wdt)
  45 {
  46         wdt->j_time_stamp = jiffies;
  47 }
  48
  49 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
  50 {
  51         unsigned int i;
  52
  53         for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
  54                 if (wdt_timeout[i] >= secs)
  55                         return i;
  56         }
  57
  58         return DA9062_TWDSCALE_MAX;
  59 }
  60
  61 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
  62 {
  63         int ret;
  64
  65         ret = regmap_update_bits(wdt->hw->regmap,
  66                            DA9062AA_CONTROL_F,
  67                            DA9062AA_WATCHDOG_MASK,
  68                            DA9062AA_WATCHDOG_MASK);
  69
  70         da9062_set_window_start(wdt);
  71
  72         return ret;
  73 }
  74
  75 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
  76                                               unsigned int regval)
  77 {
  78         struct da9062 *chip = wdt->hw;
  79         int ret;
  80
  81         ret = da9062_reset_watchdog_timer(wdt);
  82         if (ret)
  83                 return ret;
  84
  85         regmap_update_bits(chip->regmap,
  86                                   DA9062AA_CONTROL_D,
  87                                   DA9062AA_TWDSCALE_MASK,
  88                                   DA9062_TWDSCALE_DISABLE);
  89
  90         usleep_range(150, 300);
  91
  92         return regmap_update_bits(chip->regmap,
  93                                   DA9062AA_CONTROL_D,
  94                                   DA9062AA_TWDSCALE_MASK,
  95                                   regval);
  96 }
  97
  98 static int da9062_wdt_start(struct watchdog_device *wdd)
  99 {
 100         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 101         unsigned int selector;
 102         int ret;
 103
 104         selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
 105         ret = da9062_wdt_update_timeout_register(wdt, selector);
 106         if (ret)
 107                 dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
 108                         ret);
 109
 110         return ret;
 111 }
 112
 113 static int da9062_wdt_stop(struct watchdog_device *wdd)
 114 {
 115         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 116         int ret;
 117
 118         ret = da9062_reset_watchdog_timer(wdt);
 119         if (ret) {
 120                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 121                         ret);
 122                 return ret;
 123         }
 124
 125         ret = regmap_update_bits(wdt->hw->regmap,
 126                                  DA9062AA_CONTROL_D,
 127                                  DA9062AA_TWDSCALE_MASK,
 128                                  DA9062_TWDSCALE_DISABLE);
 129         if (ret)
 130                 dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
 131                         ret);
 132
 133         return ret;
 134 }
 135
 136 static int da9062_wdt_ping(struct watchdog_device *wdd)
 137 {
 138         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 139         int ret;
 140
 141         ret = da9062_reset_watchdog_timer(wdt);
 142         if (ret)
 143                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 144                         ret);
 145
 146         return ret;
 147 }
 148
 149 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
 150                                   unsigned int timeout)
 151 {
 152         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 153         unsigned int selector;
 154         int ret;
 155
 156         selector = da9062_wdt_timeout_to_sel(timeout);
 157         ret = da9062_wdt_update_timeout_register(wdt, selector);
 158         if (ret)
 159                 dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
 160                         ret);
 161         else
 162                 wdd->timeout = wdt_timeout[selector];
 163
 164         return ret;
 165 }
 166
 167 static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 168                               void *data)
 169 {
 170         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 171         int ret;
 172
 173         ret = regmap_write(wdt->hw->regmap,
 174                            DA9062AA_CONTROL_F,
 175                            DA9062AA_SHUTDOWN_MASK);
 176         if (ret)
 177                 dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
 178                           ret);
 179
 180         /* wait for reset to assert... */
 181         mdelay(500);
 182
 183         return ret;
 184 }
 185
 186 static const struct watchdog_info da9062_watchdog_info = {
 187         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 188         .identity = "DA9062 WDT",
 189 };
 190
 191 static const struct watchdog_ops da9062_watchdog_ops = {
 192         .owner = THIS_MODULE,
 193         .start = da9062_wdt_start,
 194         .stop = da9062_wdt_stop,
 195         .ping = da9062_wdt_ping,
 196         .set_timeout = da9062_wdt_set_timeout,
 197         .restart = da9062_wdt_restart,
 198 };
 199
 200 static const struct of_device_id da9062_compatible_id_table[] = {
 201         { .compatible = "dlg,da9062-watchdog", },
 202         { },
 203 };
 204
 205 MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
 206
 207 static int da9062_wdt_probe(struct platform_device *pdev)
 208 {
 209         int ret;
 210         struct da9062 *chip;
 211         struct da9062_watchdog *wdt;
 212
 213         chip = dev_get_drvdata(pdev->dev.parent);
 214         if (!chip)
 215                 return -EINVAL;
 216
 217         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 218         if (!wdt)
 219                 return -ENOMEM;
 220
 221         wdt->hw = chip;
 222
 223         wdt->wdtdev.info = &da9062_watchdog_info;
 224         wdt->wdtdev.ops = &da9062_watchdog_ops;
 225         wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
 226         wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
 227         wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
 228         wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
 229         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 230         wdt->wdtdev.parent = &pdev->dev;
 231
 232         watchdog_set_restart_priority(&wdt->wdtdev, 128);
 233
 234         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 235
 236         ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
 237         if (ret < 0) {
 238                 dev_err(wdt->hw->dev,
 239                         "watchdog registration failed (%d)\n", ret);
 240                 return ret;
 241         }
 242
 243         da9062_set_window_start(wdt);
 244
 245         return da9062_wdt_ping(&wdt->wdtdev);
 246 }
 247
 248 static struct platform_driver da9062_wdt_driver = {
 249         .probe = da9062_wdt_probe,
 250         .driver = {
 251                 .name = "da9062-watchdog",
 252                 .of_match_table = da9062_compatible_id_table,
 253         },
 254 };
 255 module_platform_driver(da9062_wdt_driver);
 256
 257 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
 258 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
 259 MODULE_LICENSE("GPL");
 260 MODULE_ALIAS("platform:da9062-watchdog");