drivers/watchdog/da9062_wdt.c

   1 /*
   2  * da9062_wdt.c - WDT device driver for DA9062
   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 void da9062_apply_window_protection(struct da9062_watchdog *wdt)
  50 {
  51         unsigned long delay = msecs_to_jiffies(DA9062_RESET_PROTECTION_MS);
  52         unsigned long timeout = wdt->j_time_stamp + delay;
  53         unsigned long now = jiffies;
  54         unsigned int diff_ms;
  55
  56         /* if time-limit has not elapsed then wait for remainder */
  57         if (time_before(now, timeout)) {
  58                 diff_ms = jiffies_to_msecs(timeout-now);
  59                 dev_dbg(wdt->hw->dev,
  60                         "Kicked too quickly. Delaying %u msecs\n", diff_ms);
  61                 msleep(diff_ms);
  62         }
  63 }
  64
  65 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
  66 {
  67         unsigned int i;
  68
  69         for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
  70                 if (wdt_timeout[i] >= secs)
  71                         return i;
  72         }
  73
  74         return DA9062_TWDSCALE_MAX;
  75 }
  76
  77 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
  78 {
  79         int ret;
  80
  81         da9062_apply_window_protection(wdt);
  82
  83         ret = regmap_update_bits(wdt->hw->regmap,
  84                            DA9062AA_CONTROL_F,
  85                            DA9062AA_WATCHDOG_MASK,
  86                            DA9062AA_WATCHDOG_MASK);
  87
  88         da9062_set_window_start(wdt);
  89
  90         return ret;
  91 }
  92
  93 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
  94                                               unsigned int regval)
  95 {
  96         struct da9062 *chip = wdt->hw;
  97         int ret;
  98
  99         ret = da9062_reset_watchdog_timer(wdt);
 100         if (ret)
 101                 return ret;
 102
 103         return regmap_update_bits(chip->regmap,
 104                                   DA9062AA_CONTROL_D,
 105                                   DA9062AA_TWDSCALE_MASK,
 106                                   regval);
 107 }
 108
 109 static int da9062_wdt_start(struct watchdog_device *wdd)
 110 {
 111         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 112         unsigned int selector;
 113         int ret;
 114
 115         selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
 116         ret = da9062_wdt_update_timeout_register(wdt, selector);
 117         if (ret)
 118                 dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
 119                         ret);
 120
 121         return ret;
 122 }
 123
 124 static int da9062_wdt_stop(struct watchdog_device *wdd)
 125 {
 126         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 127         int ret;
 128
 129         ret = da9062_reset_watchdog_timer(wdt);
 130         if (ret) {
 131                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 132                         ret);
 133                 return ret;
 134         }
 135
 136         ret = regmap_update_bits(wdt->hw->regmap,
 137                                  DA9062AA_CONTROL_D,
 138                                  DA9062AA_TWDSCALE_MASK,
 139                                  DA9062_TWDSCALE_DISABLE);
 140         if (ret)
 141                 dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
 142                         ret);
 143
 144         return ret;
 145 }
 146
 147 static int da9062_wdt_ping(struct watchdog_device *wdd)
 148 {
 149         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 150         int ret;
 151
 152         ret = da9062_reset_watchdog_timer(wdt);
 153         if (ret)
 154                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 155                         ret);
 156
 157         return ret;
 158 }
 159
 160 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
 161                                   unsigned int timeout)
 162 {
 163         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 164         unsigned int selector;
 165         int ret;
 166
 167         selector = da9062_wdt_timeout_to_sel(timeout);
 168         ret = da9062_wdt_update_timeout_register(wdt, selector);
 169         if (ret)
 170                 dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
 171                         ret);
 172         else
 173                 wdd->timeout = wdt_timeout[selector];
 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 };
 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.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
 212         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 213         wdt->wdtdev.parent = &pdev->dev;
 214
 215         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 216         dev_set_drvdata(&pdev->dev, wdt);
 217
 218         ret = watchdog_register_device(&wdt->wdtdev);
 219         if (ret < 0) {
 220                 dev_err(wdt->hw->dev,
 221                         "watchdog registration failed (%d)\n", ret);
 222                 return ret;
 223         }
 224
 225         da9062_set_window_start(wdt);
 226
 227         ret = da9062_wdt_ping(&wdt->wdtdev);
 228         if (ret < 0)
 229                 watchdog_unregister_device(&wdt->wdtdev);
 230
 231         return ret;
 232 }
 233
 234 static int da9062_wdt_remove(struct platform_device *pdev)
 235 {
 236         struct da9062_watchdog *wdt = dev_get_drvdata(&pdev->dev);
 237
 238         watchdog_unregister_device(&wdt->wdtdev);
 239         return 0;
 240 }
 241
 242 static struct platform_driver da9062_wdt_driver = {
 243         .probe = da9062_wdt_probe,
 244         .remove = da9062_wdt_remove,
 245         .driver = {
 246                 .name = "da9062-watchdog",
 247         },
 248 };
 249 module_platform_driver(da9062_wdt_driver);
 250
 251 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
 252 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062");
 253 MODULE_LICENSE("GPL");
 254 MODULE_ALIAS("platform:da9062-watchdog");