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