drivers/watchdog/wm831x_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Watchdog driver for the wm831x PMICs
   4  *
   5  * Copyright (C) 2009 Wolfson Microelectronics
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/moduleparam.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/watchdog.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/gpio.h>
  17
  18 #include <linux/mfd/wm831x/core.h>
  19 #include <linux/mfd/wm831x/pdata.h>
  20 #include <linux/mfd/wm831x/watchdog.h>
  21
  22 static bool nowayout = WATCHDOG_NOWAYOUT;
  23 module_param(nowayout, bool, 0);
  24 MODULE_PARM_DESC(nowayout,
  25                  "Watchdog cannot be stopped once started (default="
  26                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  27
  28 struct wm831x_wdt_drvdata {
  29         struct watchdog_device wdt;
  30         struct wm831x *wm831x;
  31         struct mutex lock;
  32         int update_gpio;
  33         int update_state;
  34 };
  35
  36 /* We can't use the sub-second values here but they're included
  37  * for completeness.  */
  38 static struct {
  39         unsigned int time;  /* Seconds */
  40         u16 val;            /* WDOG_TO value */
  41 } wm831x_wdt_cfgs[] = {
  42         {  1, 2 },
  43         {  2, 3 },
  44         {  4, 4 },
  45         {  8, 5 },
  46         { 16, 6 },
  47         { 32, 7 },
  48         { 33, 7 },  /* Actually 32.768s so include both, others round down */
  49 };
  50
  51 static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
  52 {
  53         struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  54         struct wm831x *wm831x = driver_data->wm831x;
  55         int ret;
  56
  57         mutex_lock(&driver_data->lock);
  58
  59         ret = wm831x_reg_unlock(wm831x);
  60         if (ret == 0) {
  61                 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
  62                                       WM831X_WDOG_ENA, WM831X_WDOG_ENA);
  63                 wm831x_reg_lock(wm831x);
  64         } else {
  65                 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  66                         ret);
  67         }
  68
  69         mutex_unlock(&driver_data->lock);
  70
  71         return ret;
  72 }
  73
  74 static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
  75 {
  76         struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  77         struct wm831x *wm831x = driver_data->wm831x;
  78         int ret;
  79
  80         mutex_lock(&driver_data->lock);
  81
  82         ret = wm831x_reg_unlock(wm831x);
  83         if (ret == 0) {
  84                 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
  85                                       WM831X_WDOG_ENA, 0);
  86                 wm831x_reg_lock(wm831x);
  87         } else {
  88                 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  89                         ret);
  90         }
  91
  92         mutex_unlock(&driver_data->lock);
  93
  94         return ret;
  95 }
  96
  97 static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
  98 {
  99         struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 100         struct wm831x *wm831x = driver_data->wm831x;
 101         int ret;
 102         u16 reg;
 103
 104         mutex_lock(&driver_data->lock);
 105
 106         if (driver_data->update_gpio) {
 107                 gpio_set_value_cansleep(driver_data->update_gpio,
 108                                         driver_data->update_state);
 109                 driver_data->update_state = !driver_data->update_state;
 110                 ret = 0;
 111                 goto out;
 112         }
 113
 114         reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
 115
 116         if (!(reg & WM831X_WDOG_RST_SRC)) {
 117                 dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
 118                 ret = -EINVAL;
 119                 goto out;
 120         }
 121
 122         reg |= WM831X_WDOG_RESET;
 123
 124         ret = wm831x_reg_unlock(wm831x);
 125         if (ret == 0) {
 126                 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
 127                 wm831x_reg_lock(wm831x);
 128         } else {
 129                 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
 130                         ret);
 131         }
 132
 133 out:
 134         mutex_unlock(&driver_data->lock);
 135
 136         return ret;
 137 }
 138
 139 static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
 140                                   unsigned int timeout)
 141 {
 142         struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 143         struct wm831x *wm831x = driver_data->wm831x;
 144         int ret, i;
 145
 146         for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
 147                 if (wm831x_wdt_cfgs[i].time == timeout)
 148                         break;
 149         if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
 150                 return -EINVAL;
 151
 152         ret = wm831x_reg_unlock(wm831x);
 153         if (ret == 0) {
 154                 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
 155                                       WM831X_WDOG_TO_MASK,
 156                                       wm831x_wdt_cfgs[i].val);
 157                 wm831x_reg_lock(wm831x);
 158         } else {
 159                 dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
 160                         ret);
 161         }
 162
 163         wdt_dev->timeout = timeout;
 164
 165         return ret;
 166 }
 167
 168 static const struct watchdog_info wm831x_wdt_info = {
 169         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 170         .identity = "WM831x Watchdog",
 171 };
 172
 173 static const struct watchdog_ops wm831x_wdt_ops = {
 174         .owner = THIS_MODULE,
 175         .start = wm831x_wdt_start,
 176         .stop = wm831x_wdt_stop,
 177         .ping = wm831x_wdt_ping,
 178         .set_timeout = wm831x_wdt_set_timeout,
 179 };
 180
 181 static int wm831x_wdt_probe(struct platform_device *pdev)
 182 {
 183         struct device *dev = &pdev->dev;
 184         struct wm831x *wm831x = dev_get_drvdata(dev->parent);
 185         struct wm831x_pdata *chip_pdata = dev_get_platdata(dev->parent);
 186         struct wm831x_watchdog_pdata *pdata;
 187         struct wm831x_wdt_drvdata *driver_data;
 188         struct watchdog_device *wm831x_wdt;
 189         int reg, ret, i;
 190
 191         ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
 192         if (ret < 0) {
 193                 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
 194                         ret);
 195                 return ret;
 196         }
 197         reg = ret;
 198
 199         if (reg & WM831X_WDOG_DEBUG)
 200                 dev_warn(wm831x->dev, "Watchdog is paused\n");
 201
 202         driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
 203         if (!driver_data)
 204                 return -ENOMEM;
 205
 206         mutex_init(&driver_data->lock);
 207         driver_data->wm831x = wm831x;
 208
 209         wm831x_wdt = &driver_data->wdt;
 210
 211         wm831x_wdt->info = &wm831x_wdt_info;
 212         wm831x_wdt->ops = &wm831x_wdt_ops;
 213         wm831x_wdt->parent = dev;
 214         watchdog_set_nowayout(wm831x_wdt, nowayout);
 215         watchdog_set_drvdata(wm831x_wdt, driver_data);
 216
 217         reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
 218         reg &= WM831X_WDOG_TO_MASK;
 219         for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
 220                 if (wm831x_wdt_cfgs[i].val == reg)
 221                         break;
 222         if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
 223                 dev_warn(wm831x->dev,
 224                          "Unknown watchdog timeout: %x\n", reg);
 225         else
 226                 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
 227
 228         /* Apply any configuration */
 229         if (chip_pdata)
 230                 pdata = chip_pdata->watchdog;
 231         else
 232                 pdata = NULL;
 233
 234         if (pdata) {
 235                 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
 236                          WM831X_WDOG_RST_SRC);
 237
 238                 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
 239                 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
 240                 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
 241
 242                 if (pdata->update_gpio) {
 243                         ret = devm_gpio_request_one(dev, pdata->update_gpio,
 244                                                     GPIOF_OUT_INIT_LOW,
 245                                                     "Watchdog update");
 246                         if (ret < 0) {
 247                                 dev_err(wm831x->dev,
 248                                         "Failed to request update GPIO: %d\n",
 249                                         ret);
 250                                 return ret;
 251                         }
 252
 253                         driver_data->update_gpio = pdata->update_gpio;
 254
 255                         /* Make sure the watchdog takes hardware updates */
 256                         reg |= WM831X_WDOG_RST_SRC;
 257                 }
 258
 259                 ret = wm831x_reg_unlock(wm831x);
 260                 if (ret == 0) {
 261                         ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
 262                         wm831x_reg_lock(wm831x);
 263                 } else {
 264                         dev_err(wm831x->dev,
 265                                 "Failed to unlock security key: %d\n", ret);
 266                         return ret;
 267                 }
 268         }
 269
 270         return devm_watchdog_register_device(dev, &driver_data->wdt);
 271 }
 272
 273 static struct platform_driver wm831x_wdt_driver = {
 274         .probe = wm831x_wdt_probe,
 275         .driver = {
 276                 .name = "wm831x-watchdog",
 277         },
 278 };
 279
 280 module_platform_driver(wm831x_wdt_driver);
 281
 282 MODULE_AUTHOR("Mark Brown");
 283 MODULE_DESCRIPTION("WM831x Watchdog");
 284 MODULE_LICENSE("GPL");
 285 MODULE_ALIAS("platform:wm831x-watchdog");