drivers/watchdog/da9052_wdt.c

   1 /*
   2  * System monitoring driver for DA9052 PMICs.
   3  *
   4  * Copyright(c) 2012 Dialog Semiconductor Ltd.
   5  *
   6  * Author: Anthony Olech <Anthony.Olech@diasemi.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/delay.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/time.h>
  20 #include <linux/watchdog.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/jiffies.h>
  24
  25 #include <linux/mfd/da9052/reg.h>
  26 #include <linux/mfd/da9052/da9052.h>
  27
  28 #define DA9052_DEF_TIMEOUT      4
  29 #define DA9052_TWDMIN           256
  30
  31 struct da9052_wdt_data {
  32         struct watchdog_device wdt;
  33         struct da9052 *da9052;
  34         struct kref kref;
  35         unsigned long jpast;
  36 };
  37
  38 static const struct {
  39         u8 reg_val;
  40         int time;  /* Seconds */
  41 } da9052_wdt_maps[] = {
  42         { 1, 2 },
  43         { 2, 4 },
  44         { 3, 8 },
  45         { 4, 16 },
  46         { 5, 32 },
  47         { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
  48         { 6, 65 },
  49         { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
  50         { 7, 131 },
  51 };
  52
  53
  54 static void da9052_wdt_release_resources(struct kref *r)
  55 {
  56         struct da9052_wdt_data *driver_data =
  57                 container_of(r, struct da9052_wdt_data, kref);
  58
  59         kfree(driver_data);
  60 }
  61
  62 static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
  63                                   unsigned int timeout)
  64 {
  65         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  66         struct da9052 *da9052 = driver_data->da9052;
  67         int ret, i;
  68
  69         /*
  70          * Disable the Watchdog timer before setting
  71          * new time out.
  72          */
  73         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  74                                 DA9052_CONTROLD_TWDSCALE, 0);
  75         if (ret < 0) {
  76                 dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
  77                         ret);
  78                 return ret;
  79         }
  80         if (timeout) {
  81                 /*
  82                  * To change the timeout, da9052 needs to
  83                  * be disabled for at least 150 us.
  84                  */
  85                 udelay(150);
  86
  87                 /* Set the desired timeout */
  88                 for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
  89                         if (da9052_wdt_maps[i].time == timeout)
  90                                 break;
  91
  92                 if (i == ARRAY_SIZE(da9052_wdt_maps))
  93                         ret = -EINVAL;
  94                 else
  95                         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  96                                                 DA9052_CONTROLD_TWDSCALE,
  97                                                 da9052_wdt_maps[i].reg_val);
  98                 if (ret < 0) {
  99                         dev_err(da9052->dev,
 100                                 "Failed to update timescale bit, %d\n", ret);
 101                         return ret;
 102                 }
 103
 104                 wdt_dev->timeout = timeout;
 105                 driver_data->jpast = jiffies;
 106         }
 107
 108         return 0;
 109 }
 110
 111 static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
 112 {
 113         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 114
 115         kref_get(&driver_data->kref);
 116 }
 117
 118 static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
 119 {
 120         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 121
 122         kref_put(&driver_data->kref, da9052_wdt_release_resources);
 123 }
 124
 125 static int da9052_wdt_start(struct watchdog_device *wdt_dev)
 126 {
 127         return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 128 }
 129
 130 static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
 131 {
 132         return da9052_wdt_set_timeout(wdt_dev, 0);
 133 }
 134
 135 static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
 136 {
 137         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 138         struct da9052 *da9052 = driver_data->da9052;
 139         unsigned long msec, jnow = jiffies;
 140         int ret;
 141
 142         /*
 143          * We have a minimum time for watchdog window called TWDMIN. A write
 144          * to the watchdog before this elapsed time should cause an error.
 145          */
 146         msec = (jnow - driver_data->jpast) * 1000/HZ;
 147         if (msec < DA9052_TWDMIN)
 148                 mdelay(msec);
 149
 150         /* Reset the watchdog timer */
 151         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 152                                 DA9052_CONTROLD_WATCHDOG, 1 << 7);
 153         if (ret < 0)
 154                 goto err_strobe;
 155
 156         /*
 157          * FIXME: Reset the watchdog core, in general PMIC
 158          * is supposed to do this
 159          */
 160         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 161                                 DA9052_CONTROLD_WATCHDOG, 0 << 7);
 162 err_strobe:
 163         return ret;
 164 }
 165
 166 static struct watchdog_info da9052_wdt_info = {
 167         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 168         .identity       = "DA9052 Watchdog",
 169 };
 170
 171 static const struct watchdog_ops da9052_wdt_ops = {
 172         .owner = THIS_MODULE,
 173         .start = da9052_wdt_start,
 174         .stop = da9052_wdt_stop,
 175         .ping = da9052_wdt_ping,
 176         .set_timeout = da9052_wdt_set_timeout,
 177         .ref = da9052_wdt_ref,
 178         .unref = da9052_wdt_unref,
 179 };
 180
 181
 182 static int __devinit da9052_wdt_probe(struct platform_device *pdev)
 183 {
 184         struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
 185         struct da9052_wdt_data *driver_data;
 186         struct watchdog_device *da9052_wdt;
 187         int ret;
 188
 189         driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
 190                                    GFP_KERNEL);
 191         if (!driver_data) {
 192                 dev_err(da9052->dev, "Unable to alloacate watchdog device\n");
 193                 ret = -ENOMEM;
 194                 goto err;
 195         }
 196         driver_data->da9052 = da9052;
 197
 198         da9052_wdt = &driver_data->wdt;
 199
 200         da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
 201         da9052_wdt->info = &da9052_wdt_info;
 202         da9052_wdt->ops = &da9052_wdt_ops;
 203         watchdog_set_drvdata(da9052_wdt, driver_data);
 204
 205         kref_init(&driver_data->kref);
 206
 207         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 208                                 DA9052_CONTROLD_TWDSCALE, 0);
 209         if (ret < 0) {
 210                 dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
 211                         ret);
 212                 goto err;
 213         }
 214
 215         ret = watchdog_register_device(&driver_data->wdt);
 216         if (ret != 0) {
 217                 dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
 218                         ret);
 219                 goto err;
 220         }
 221
 222         dev_set_drvdata(&pdev->dev, driver_data);
 223 err:
 224         return ret;
 225 }
 226
 227 static int __devexit da9052_wdt_remove(struct platform_device *pdev)
 228 {
 229         struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
 230
 231         watchdog_unregister_device(&driver_data->wdt);
 232         kref_put(&driver_data->kref, da9052_wdt_release_resources);
 233
 234         return 0;
 235 }
 236
 237 static struct platform_driver da9052_wdt_driver = {
 238         .probe = da9052_wdt_probe,
 239         .remove = __devexit_p(da9052_wdt_remove),
 240         .driver = {
 241                 .name   = "da9052-watchdog",
 242         },
 243 };
 244
 245 module_platform_driver(da9052_wdt_driver);
 246
 247 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
 248 MODULE_DESCRIPTION("DA9052 SM Device Driver");
 249 MODULE_LICENSE("GPL");
 250 MODULE_ALIAS("platform:da9052-watchdog");