LXR linux/drivers/watchdog/da9052

   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
  27struct da9052_wdt_data {
  28        struct watchdog_device wdt;
  29        struct da9052 *da9052;
  30        unsigned long jpast;
  31};
  32
  33static 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
  49static 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
  98static int da9052_wdt_start(struct watchdog_device *wdt_dev)
  99{
 100        return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 101}
 102
 103static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
 104{
 105        return da9052_wdt_set_timeout(wdt_dev, 0);
 106}
 107
 108static 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
 137static const struct watchdog_info da9052_wdt_info = {
 138        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 139        .identity       = "DA9052 Watchdog",
 140};
 141
 142static 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
 151static 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
 182static struct platform_driver da9052_wdt_driver = {
 183        .probe = da9052_wdt_probe,
 184        .driver = {
 185                .name   = "da9052-watchdog",
 186        },
 187};
 188
 189module_platform_driver(da9052_wdt_driver);
 190
 191MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
 192MODULE_DESCRIPTION("DA9052 SM Device Driver");
 193MODULE_LICENSE("GPL");
 194MODULE_ALIAS("platform:da9052-watchdog");
 195