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/i2c.h>
  15 #include <linux/delay.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/mfd/da9062/registers.h>
  18 #include <linux/mfd/da9062/core.h>
  19 #include <linux/property.h>
  20 #include <linux/regmap.h>
  21 #include <linux/of.h>
  22
  23 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  24 #define DA9062_TWDSCALE_DISABLE         0
  25 #define DA9062_TWDSCALE_MIN             1
  26 #define DA9062_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  27 #define DA9062_WDT_MIN_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MIN]
  28 #define DA9062_WDT_MAX_TIMEOUT          wdt_timeout[DA9062_TWDSCALE_MAX]
  29 #define DA9062_WDG_DEFAULT_TIMEOUT      wdt_timeout[DA9062_TWDSCALE_MAX-1]
  30 #define DA9062_RESET_PROTECTION_MS      300
  31
  32 struct da9062_watchdog {
  33         struct da9062 *hw;
  34         struct watchdog_device wdtdev;
  35         bool use_sw_pm;
  36 };
  37
  38 static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
  39 {
  40         unsigned int val;
  41
  42         regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
  43
  44         return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
  45 }
  46
  47 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
  48 {
  49         unsigned int i;
  50
  51         for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
  52                 if (wdt_timeout[i] >= secs)
  53                         return i;
  54         }
  55
  56         return DA9062_TWDSCALE_MAX;
  57 }
  58
  59 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
  60 {
  61         return regmap_update_bits(wdt->hw->regmap, DA9062AA_CONTROL_F,
  62                                   DA9062AA_WATCHDOG_MASK,
  63                                   DA9062AA_WATCHDOG_MASK);
  64 }
  65
  66 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
  67                                               unsigned int regval)
  68 {
  69         struct da9062 *chip = wdt->hw;
  70
  71         regmap_update_bits(chip->regmap,
  72                                   DA9062AA_CONTROL_D,
  73                                   DA9062AA_TWDSCALE_MASK,
  74                                   DA9062_TWDSCALE_DISABLE);
  75
  76         usleep_range(150, 300);
  77
  78         return regmap_update_bits(chip->regmap,
  79                                   DA9062AA_CONTROL_D,
  80                                   DA9062AA_TWDSCALE_MASK,
  81                                   regval);
  82 }
  83
  84 static int da9062_wdt_start(struct watchdog_device *wdd)
  85 {
  86         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
  87         unsigned int selector;
  88         int ret;
  89
  90         selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
  91         ret = da9062_wdt_update_timeout_register(wdt, selector);
  92         if (ret)
  93                 dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
  94                         ret);
  95
  96         return ret;
  97 }
  98
  99 static int da9062_wdt_stop(struct watchdog_device *wdd)
 100 {
 101         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 102         int ret;
 103
 104         ret = regmap_update_bits(wdt->hw->regmap,
 105                                  DA9062AA_CONTROL_D,
 106                                  DA9062AA_TWDSCALE_MASK,
 107                                  DA9062_TWDSCALE_DISABLE);
 108         if (ret)
 109                 dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
 110                         ret);
 111
 112         return ret;
 113 }
 114
 115 static int da9062_wdt_ping(struct watchdog_device *wdd)
 116 {
 117         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 118         int ret;
 119
 120         /*
 121          * Prevent pings from occurring late in system poweroff/reboot sequence
 122          * and possibly locking out restart handler from accessing i2c bus.
 123          */
 124         if (system_state > SYSTEM_RUNNING)
 125                 return 0;
 126
 127         ret = da9062_reset_watchdog_timer(wdt);
 128         if (ret)
 129                 dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
 130                         ret);
 131
 132         return ret;
 133 }
 134
 135 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
 136                                   unsigned int timeout)
 137 {
 138         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 139         unsigned int selector;
 140         int ret;
 141
 142         selector = da9062_wdt_timeout_to_sel(timeout);
 143         ret = da9062_wdt_update_timeout_register(wdt, selector);
 144         if (ret)
 145                 dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
 146                         ret);
 147         else
 148                 wdd->timeout = wdt_timeout[selector];
 149
 150         return ret;
 151 }
 152
 153 static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 154                               void *data)
 155 {
 156         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 157         struct i2c_client *client = to_i2c_client(wdt->hw->dev);
 158         union i2c_smbus_data msg;
 159         int ret;
 160
 161         /*
 162          * Don't use regmap because it is not atomic safe. Additionally, use
 163          * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
 164          * might be previously locked by some process unable to release the
 165          * lock due to interrupts already being disabled at this late stage.
 166          */
 167         msg.byte = DA9062AA_SHUTDOWN_MASK;
 168         ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 169                                I2C_SMBUS_WRITE, DA9062AA_CONTROL_F,
 170                                I2C_SMBUS_BYTE_DATA, &msg);
 171
 172         if (ret < 0)
 173                 dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
 174                           ret);
 175
 176         /* wait for reset to assert... */
 177         mdelay(500);
 178
 179         return ret;
 180 }
 181
 182 static const struct watchdog_info da9062_watchdog_info = {
 183         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 184         .identity = "DA9062 WDT",
 185 };
 186
 187 static const struct watchdog_ops da9062_watchdog_ops = {
 188         .owner = THIS_MODULE,
 189         .start = da9062_wdt_start,
 190         .stop = da9062_wdt_stop,
 191         .ping = da9062_wdt_ping,
 192         .set_timeout = da9062_wdt_set_timeout,
 193         .restart = da9062_wdt_restart,
 194 };
 195
 196 static const struct of_device_id da9062_compatible_id_table[] = {
 197         { .compatible = "dlg,da9062-watchdog", },
 198         { },
 199 };
 200
 201 MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
 202
 203 static int da9062_wdt_probe(struct platform_device *pdev)
 204 {
 205         struct device *dev = &pdev->dev;
 206         unsigned int timeout;
 207         struct da9062 *chip;
 208         struct da9062_watchdog *wdt;
 209
 210         chip = dev_get_drvdata(dev->parent);
 211         if (!chip)
 212                 return -EINVAL;
 213
 214         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 215         if (!wdt)
 216                 return -ENOMEM;
 217
 218         wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
 219
 220         wdt->hw = chip;
 221
 222         wdt->wdtdev.info = &da9062_watchdog_info;
 223         wdt->wdtdev.ops = &da9062_watchdog_ops;
 224         wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
 225         wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
 226         wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
 227         wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
 228         wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 229         wdt->wdtdev.parent = dev;
 230
 231         watchdog_set_restart_priority(&wdt->wdtdev, 128);
 232
 233         watchdog_set_drvdata(&wdt->wdtdev, wdt);
 234         dev_set_drvdata(dev, &wdt->wdtdev);
 235
 236         timeout = da9062_wdt_read_timeout(wdt);
 237         if (timeout)
 238                 wdt->wdtdev.timeout = timeout;
 239
 240         /* Set timeout from DT value if available */
 241         watchdog_init_timeout(&wdt->wdtdev, 0, dev);
 242
 243         if (timeout) {
 244                 da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
 245                 set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
 246         }
 247
 248         return devm_watchdog_register_device(dev, &wdt->wdtdev);
 249 }
 250
 251 static int __maybe_unused da9062_wdt_suspend(struct device *dev)
 252 {
 253         struct watchdog_device *wdd = dev_get_drvdata(dev);
 254         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 255
 256         if (!wdt->use_sw_pm)
 257                 return 0;
 258
 259         if (watchdog_active(wdd))
 260                 return da9062_wdt_stop(wdd);
 261
 262         return 0;
 263 }
 264
 265 static int __maybe_unused da9062_wdt_resume(struct device *dev)
 266 {
 267         struct watchdog_device *wdd = dev_get_drvdata(dev);
 268         struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 269
 270         if (!wdt->use_sw_pm)
 271                 return 0;
 272
 273         if (watchdog_active(wdd))
 274                 return da9062_wdt_start(wdd);
 275
 276         return 0;
 277 }
 278
 279 static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
 280                          da9062_wdt_suspend, da9062_wdt_resume);
 281
 282 static struct platform_driver da9062_wdt_driver = {
 283         .probe = da9062_wdt_probe,
 284         .driver = {
 285                 .name = "da9062-watchdog",
 286                 .pm = &da9062_wdt_pm_ops,
 287                 .of_match_table = da9062_compatible_id_table,
 288         },
 289 };
 290 module_platform_driver(da9062_wdt_driver);
 291
 292 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
 293 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
 294 MODULE_LICENSE("GPL");
 295 MODULE_ALIAS("platform:da9062-watchdog");