LXR linux/drivers/watchdog/da9055

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * System monitoring driver for DA9055 PMICs.
   4 *
   5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
   6 *
   7 * Author: David Dajun Chen <dchen@diasemi.com>
   8 *
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/types.h>
  13#include <linux/kernel.h>
  14#include <linux/slab.h>
  15#include <linux/platform_device.h>
  16#include <linux/watchdog.h>
  17#include <linux/delay.h>
  18
  19#include <linux/mfd/da9055/core.h>
  20#include <linux/mfd/da9055/reg.h>
  21
  22static bool nowayout = WATCHDOG_NOWAYOUT;
  23module_param(nowayout, bool, 0);
  24MODULE_PARM_DESC(nowayout,
  25                 "Watchdog cannot be stopped once started (default="
  26                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  27
  28#define DA9055_DEF_TIMEOUT      4
  29#define DA9055_TWDMIN           256
  30
  31struct da9055_wdt_data {
  32        struct watchdog_device wdt;
  33        struct da9055 *da9055;
  34};
  35
  36static const struct {
  37        u8 reg_val;
  38        int user_time;  /* In seconds */
  39} da9055_wdt_maps[] = {
  40        { 0, 0 },
  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
  52static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
  53                                  unsigned int timeout)
  54{
  55        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  56        struct da9055 *da9055 = driver_data->da9055;
  57        int ret, i;
  58
  59        for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
  60                if (da9055_wdt_maps[i].user_time == timeout)
  61                        break;
  62
  63        if (i == ARRAY_SIZE(da9055_wdt_maps))
  64                ret = -EINVAL;
  65        else
  66                ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
  67                                        DA9055_TWDSCALE_MASK,
  68                                        da9055_wdt_maps[i].reg_val <<
  69                                        DA9055_TWDSCALE_SHIFT);
  70        if (ret < 0) {
  71                dev_err(da9055->dev,
  72                        "Failed to update timescale bit, %d\n", ret);
  73                return ret;
  74        }
  75
  76        wdt_dev->timeout = timeout;
  77
  78        return 0;
  79}
  80
  81static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
  82{
  83        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
  84        struct da9055 *da9055 = driver_data->da9055;
  85
  86        /*
  87         * We have a minimum time for watchdog window called TWDMIN. A write
  88         * to the watchdog before this elapsed time will cause an error.
  89         */
  90        mdelay(DA9055_TWDMIN);
  91
  92        /* Reset the watchdog timer */
  93        return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
  94                                 DA9055_WATCHDOG_MASK, 1);
  95}
  96
  97static int da9055_wdt_start(struct watchdog_device *wdt_dev)
  98{
  99        return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 100}
 101
 102static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
 103{
 104        return da9055_wdt_set_timeout(wdt_dev, 0);
 105}
 106
 107static const struct watchdog_info da9055_wdt_info = {
 108        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 109        .identity       = "DA9055 Watchdog",
 110};
 111
 112static const struct watchdog_ops da9055_wdt_ops = {
 113        .owner = THIS_MODULE,
 114        .start = da9055_wdt_start,
 115        .stop = da9055_wdt_stop,
 116        .ping = da9055_wdt_ping,
 117        .set_timeout = da9055_wdt_set_timeout,
 118};
 119
 120static int da9055_wdt_probe(struct platform_device *pdev)
 121{
 122        struct device *dev = &pdev->dev;
 123        struct da9055 *da9055 = dev_get_drvdata(dev->parent);
 124        struct da9055_wdt_data *driver_data;
 125        struct watchdog_device *da9055_wdt;
 126        int ret;
 127
 128        driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
 129        if (!driver_data)
 130                return -ENOMEM;
 131
 132        driver_data->da9055 = da9055;
 133
 134        da9055_wdt = &driver_data->wdt;
 135
 136        da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
 137        da9055_wdt->info = &da9055_wdt_info;
 138        da9055_wdt->ops = &da9055_wdt_ops;
 139        da9055_wdt->parent = dev;
 140        watchdog_set_nowayout(da9055_wdt, nowayout);
 141        watchdog_set_drvdata(da9055_wdt, driver_data);
 142
 143        ret = da9055_wdt_stop(da9055_wdt);
 144        if (ret < 0) {
 145                dev_err(dev, "Failed to stop watchdog, %d\n", ret);
 146                return ret;
 147        }
 148
 149        ret = devm_watchdog_register_device(dev, &driver_data->wdt);
 150        if (ret != 0)
 151                dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
 152                        ret);
 153
 154        return ret;
 155}
 156
 157static struct platform_driver da9055_wdt_driver = {
 158        .probe = da9055_wdt_probe,
 159        .driver = {
 160                .name   = "da9055-watchdog",
 161        },
 162};
 163
 164module_platform_driver(da9055_wdt_driver);
 165
 166MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
 167MODULE_DESCRIPTION("DA9055 watchdog");
 168MODULE_LICENSE("GPL");
 169MODULE_ALIAS("platform:da9055-watchdog");
 170