drivers/watchdog/da9052_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * System monitoring driver for DA9052 PMICs.
   4  *
   5  * Copyright(c) 2012 Dialog Semiconductor Ltd.
   6  *
   7  * Author: Anthony Olech <Anthony.Olech@diasemi.com>
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/delay.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/time.h>
  16 #include <linux/watchdog.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/jiffies.h>
  20
  21 #include <linux/mfd/da9052/reg.h>
  22 #include <linux/mfd/da9052/da9052.h>
  23
  24 #define DA9052_DEF_TIMEOUT      4
  25 #define DA9052_TWDMIN           256
  26
  27 struct da9052_wdt_data {
  28         struct watchdog_device wdt;
  29         struct da9052 *da9052;
  30         unsigned long jpast;
  31 };
  32
  33 static const struct {
  34         u8 reg_val;
  35         int time;  /* Seconds */
  36 } da9052_wdt_maps[] = {
  37         { 1, 2 },
  38         { 2, 4 },
  39         { 3, 8 },
  40         { 4, 16 },
  41         { 5, 32 },
  42         { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
  43         { 6, 65 },
  44         { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
  45         { 7, 131 },
  46 };
  47
  48
  49 static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
  50                                   unsigned int timeout)
  51 {
  52         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  53         struct da9052 *da9052 = driver_data->da9052;
  54         int ret, i;
  55
  56         /*
  57          * Disable the Watchdog timer before setting
  58          * new time out.
  59          */
  60         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  61                                 DA9052_CONTROLD_TWDSCALE, 0);
  62         if (ret < 0) {
  63                 dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
  64                         ret);
  65                 return ret;
  66         }
  67         if (timeout) {
  68                 /*
  69                  * To change the timeout, da9052 needs to
  70                  * be disabled for at least 150 us.
  71                  */
  72                 udelay(150);
  73
  74                 /* Set the desired timeout */
  75                 for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
  76                         if (da9052_wdt_maps[i].time == timeout)
  77                                 break;
  78
  79                 if (i == ARRAY_SIZE(da9052_wdt_maps))
  80                         ret = -EINVAL;
  81                 else
  82                         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
  83                                                 DA9052_CONTROLD_TWDSCALE,
  84                                                 da9052_wdt_maps[i].reg_val);
  85                 if (ret < 0) {
  86                         dev_err(da9052->dev,
  87                                 "Failed to update timescale bit, %d\n", ret);
  88                         return ret;
  89                 }
  90
  91                 wdt_dev->timeout = timeout;
  92                 driver_data->jpast = jiffies;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int da9052_wdt_start(struct watchdog_device *wdt_dev)
  99 {
 100         return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 101 }
 102
 103 static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
 104 {
 105         return da9052_wdt_set_timeout(wdt_dev, 0);
 106 }
 107
 108 static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
 109 {
 110         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 111         struct da9052 *da9052 = driver_data->da9052;
 112         unsigned long msec, jnow = jiffies;
 113         int ret;
 114
 115         /*
 116          * We have a minimum time for watchdog window called TWDMIN. A write
 117          * to the watchdog before this elapsed time should cause an error.
 118          */
 119         msec = (jnow - driver_data->jpast) * 1000/HZ;
 120         if (msec < DA9052_TWDMIN)
 121                 mdelay(msec);
 122
 123         /* Reset the watchdog timer */
 124         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 125                                 DA9052_CONTROLD_WATCHDOG, 1 << 7);
 126         if (ret < 0)
 127                 return ret;
 128
 129         /*
 130          * FIXME: Reset the watchdog core, in general PMIC
 131          * is supposed to do this
 132          */
 133         return da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 134                                  DA9052_CONTROLD_WATCHDOG, 0 << 7);
 135 }
 136
 137 static const struct watchdog_info da9052_wdt_info = {
 138         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 139         .identity       = "DA9052 Watchdog",
 140 };
 141
 142 static const struct watchdog_ops da9052_wdt_ops = {
 143         .owner = THIS_MODULE,
 144         .start = da9052_wdt_start,
 145         .stop = da9052_wdt_stop,
 146         .ping = da9052_wdt_ping,
 147         .set_timeout = da9052_wdt_set_timeout,
 148 };
 149
 150
 151 static int da9052_wdt_probe(struct platform_device *pdev)
 152 {
 153         struct device *dev = &pdev->dev;
 154         struct da9052 *da9052 = dev_get_drvdata(dev->parent);
 155         struct da9052_wdt_data *driver_data;
 156         struct watchdog_device *da9052_wdt;
 157         int ret;
 158
 159         driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
 160         if (!driver_data)
 161                 return -ENOMEM;
 162         driver_data->da9052 = da9052;
 163
 164         da9052_wdt = &driver_data->wdt;
 165
 166         da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
 167         da9052_wdt->info = &da9052_wdt_info;
 168         da9052_wdt->ops = &da9052_wdt_ops;
 169         da9052_wdt->parent = dev;
 170         watchdog_set_drvdata(da9052_wdt, driver_data);
 171
 172         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 173                                 DA9052_CONTROLD_TWDSCALE, 0);
 174         if (ret < 0) {
 175                 dev_err(dev, "Failed to disable watchdog bits, %d\n", ret);
 176                 return ret;
 177         }
 178
 179         return devm_watchdog_register_device(dev, &driver_data->wdt);
 180 }
 181
 182 static struct platform_driver da9052_wdt_driver = {
 183         .probe = da9052_wdt_probe,
 184         .driver = {
 185                 .name   = "da9052-watchdog",
 186         },
 187 };
 188
 189 module_platform_driver(da9052_wdt_driver);
 190
 191 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
 192 MODULE_DESCRIPTION("DA9052 SM Device Driver");
 193 MODULE_LICENSE("GPL");
 194 MODULE_ALIAS("platform:da9052-watchdog");