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