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 }
  57
  58 static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
  59                                   unsigned int timeout)
  60 {
  61         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  62         struct da9052 *da9052 = driver_data->da9052;
  63         int ret, i;
  64
  65         /*
  66          * Disable the Watchdog timer before setting
  67          * new time out.
  68          */
  69         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  70                                 DA9052_CONTROLD_TWDSCALE, 0);
  71         if (ret < 0) {
  72                 dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
  73                         ret);
  74                 return ret;
  75         }
  76         if (timeout) {
  77                 /*
  78                  * To change the timeout, da9052 needs to
  79                  * be disabled for at least 150 us.
  80                  */
  81                 udelay(150);
  82
  83                 /* Set the desired timeout */
  84                 for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
  85                         if (da9052_wdt_maps[i].time == timeout)
  86                                 break;
  87
  88                 if (i == ARRAY_SIZE(da9052_wdt_maps))
  89                         ret = -EINVAL;
  90                 else
  91                         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  92                                                 DA9052_CONTROLD_TWDSCALE,
  93                                                 da9052_wdt_maps[i].reg_val);
  94                 if (ret < 0) {
  95                         dev_err(da9052->dev,
  96                                 "Failed to update timescale bit, %d\n", ret);
  97                         return ret;
  98                 }
  99
 100                 wdt_dev->timeout = timeout;
 101                 driver_data->jpast = jiffies;
 102         }
 103
 104         return 0;
 105 }
 106
 107 static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
 108 {
 109         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 110
 111         kref_get(&driver_data->kref);
 112 }
 113
 114 static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
 115 {
 116         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 117
 118         kref_put(&driver_data->kref, da9052_wdt_release_resources);
 119 }
 120
 121 static int da9052_wdt_start(struct watchdog_device *wdt_dev)
 122 {
 123         return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 124 }
 125
 126 static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
 127 {
 128         return da9052_wdt_set_timeout(wdt_dev, 0);
 129 }
 130
 131 static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
 132 {
 133         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 134         struct da9052 *da9052 = driver_data->da9052;
 135         unsigned long msec, jnow = jiffies;
 136         int ret;
 137
 138         /*
 139          * We have a minimum time for watchdog window called TWDMIN. A write
 140          * to the watchdog before this elapsed time should cause an error.
 141          */
 142         msec = (jnow - driver_data->jpast) * 1000/HZ;
 143         if (msec < DA9052_TWDMIN)
 144                 mdelay(msec);
 145
 146         /* Reset the watchdog timer */
 147         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 148                                 DA9052_CONTROLD_WATCHDOG, 1 << 7);
 149         if (ret < 0)
 150                 goto err_strobe;
 151
 152         /*
 153          * FIXME: Reset the watchdog core, in general PMIC
 154          * is supposed to do this
 155          */
 156         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 157                                 DA9052_CONTROLD_WATCHDOG, 0 << 7);
 158 err_strobe:
 159         return ret;
 160 }
 161
 162 static struct watchdog_info da9052_wdt_info = {
 163         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 164         .identity       = "DA9052 Watchdog",
 165 };
 166
 167 static const struct watchdog_ops da9052_wdt_ops = {
 168         .owner = THIS_MODULE,
 169         .start = da9052_wdt_start,
 170         .stop = da9052_wdt_stop,
 171         .ping = da9052_wdt_ping,
 172         .set_timeout = da9052_wdt_set_timeout,
 173         .ref = da9052_wdt_ref,
 174         .unref = da9052_wdt_unref,
 175 };
 176
 177
 178 static int da9052_wdt_probe(struct platform_device *pdev)
 179 {
 180         struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
 181         struct da9052_wdt_data *driver_data;
 182         struct watchdog_device *da9052_wdt;
 183         int ret;
 184
 185         driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
 186                                    GFP_KERNEL);
 187         if (!driver_data) {
 188                 dev_err(da9052->dev, "Unable to alloacate watchdog device\n");
 189                 ret = -ENOMEM;
 190                 goto err;
 191         }
 192         driver_data->da9052 = da9052;
 193
 194         da9052_wdt = &driver_data->wdt;
 195
 196         da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
 197         da9052_wdt->info = &da9052_wdt_info;
 198         da9052_wdt->ops = &da9052_wdt_ops;
 199         watchdog_set_drvdata(da9052_wdt, driver_data);
 200
 201         kref_init(&driver_data->kref);
 202
 203         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 204                                 DA9052_CONTROLD_TWDSCALE, 0);
 205         if (ret < 0) {
 206                 dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
 207                         ret);
 208                 goto err;
 209         }
 210
 211         ret = watchdog_register_device(&driver_data->wdt);
 212         if (ret != 0) {
 213                 dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
 214                         ret);
 215                 goto err;
 216         }
 217
 218         dev_set_drvdata(&pdev->dev, driver_data);
 219 err:
 220         return ret;
 221 }
 222
 223 static int da9052_wdt_remove(struct platform_device *pdev)
 224 {
 225         struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
 226
 227         watchdog_unregister_device(&driver_data->wdt);
 228         kref_put(&driver_data->kref, da9052_wdt_release_resources);
 229
 230         return 0;
 231 }
 232
 233 static struct platform_driver da9052_wdt_driver = {
 234         .probe = da9052_wdt_probe,
 235         .remove = da9052_wdt_remove,
 236         .driver = {
 237                 .name   = "da9052-watchdog",
 238         },
 239 };
 240
 241 module_platform_driver(da9052_wdt_driver);
 242
 243 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
 244 MODULE_DESCRIPTION("DA9052 SM Device Driver");
 245 MODULE_LICENSE("GPL");
 246 MODULE_ALIAS("platform:da9052-watchdog");