Quellcode-Bibliothek rn5t618_wdt.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Watchdog driver for Ricoh RN5T618 PMIC
 *
 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
 */

#include <linux/device.h>
#include <linux/mfd/rn5t618.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

#define DRIVER_NAME "rn5t618-wdt"

static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout;

module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");

module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
   __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

struct rn5t618_wdt {
 struct watchdog_device wdt_dev;
 struct rn5t618 *rn5t618;
};

/*
 * This array encodes the values of WDOGTIM field for the supported
 * watchdog expiration times. If the watchdog is not accessed before
 * the timer expiration, the PMU generates an interrupt and if the CPU
 * doesn't clear it within one second the system is restarted.
 */
static const struct {
 u8 reg_val;
 unsigned int time;
} rn5t618_wdt_map[] = {
 { 0, 1 },
 { 1, 8 },
 { 2, 32 },
 { 3, 128 },
};

static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
       unsigned int t)
{
 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
 int ret, i;

 for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
  if (rn5t618_wdt_map[i].time + 1 >= t)
   break;
 }

 if (i == ARRAY_SIZE(rn5t618_wdt_map))
  return -EINVAL;

 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
     RN5T618_WATCHDOG_WDOGTIM_M,
     rn5t618_wdt_map[i].reg_val);
 if (!ret)
  wdt_dev->timeout = rn5t618_wdt_map[i].time;

 return ret;
}

static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
{
 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
 int ret;

 ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 if (ret)
  return ret;

 /* enable repower-on */
 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
     RN5T618_REPCNT_REPWRON,
     RN5T618_REPCNT_REPWRON);
 if (ret)
  return ret;

 /* enable watchdog */
 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
     RN5T618_WATCHDOG_WDOGEN,
     RN5T618_WATCHDOG_WDOGEN);
 if (ret)
  return ret;

 /* enable watchdog interrupt */
 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
      RN5T618_PWRIRQ_IR_WDOG,
      RN5T618_PWRIRQ_IR_WDOG);
}

static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
{
 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);

 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
      RN5T618_WATCHDOG_WDOGEN, 0);
}

static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
{
 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
 unsigned int val;
 int ret;

 /* The counter is restarted after a R/W access to watchdog register */
 ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
 if (ret)
  return ret;

 ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
 if (ret)
  return ret;

 /* Clear pending watchdog interrupt */
 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
      RN5T618_PWRIRQ_IR_WDOG, 0);
}

static const struct watchdog_info rn5t618_wdt_info = {
 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
     WDIOF_KEEPALIVEPING,
 .identity = DRIVER_NAME,
};

static const struct watchdog_ops rn5t618_wdt_ops = {
 .owner          = THIS_MODULE,
 .start          = rn5t618_wdt_start,
 .stop           = rn5t618_wdt_stop,
 .ping           = rn5t618_wdt_ping,
 .set_timeout    = rn5t618_wdt_set_timeout,
};

static int rn5t618_wdt_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 struct rn5t618 *rn5t618 = dev_get_drvdata(dev->parent);
 struct rn5t618_wdt *wdt;
 int min_timeout, max_timeout;
 int ret;
 unsigned int val;

 wdt = devm_kzalloc(dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
 if (!wdt)
  return -ENOMEM;

 min_timeout = rn5t618_wdt_map[0].time;
 max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;

 wdt->rn5t618 = rn5t618;
 wdt->wdt_dev.info = &rn5t618_wdt_info;
 wdt->wdt_dev.ops = &rn5t618_wdt_ops;
 wdt->wdt_dev.min_timeout = min_timeout;
 wdt->wdt_dev.max_timeout = max_timeout;
 wdt->wdt_dev.timeout = max_timeout;
 wdt->wdt_dev.parent = dev;

 /* Read out previous power-off factor */
 ret = regmap_read(wdt->rn5t618->regmap, RN5T618_POFFHIS, &val);
 if (ret)
  return ret;

 if (val & RN5T618_POFFHIS_VINDET)
  wdt->wdt_dev.bootstatus = WDIOF_POWERUNDER;
 else if (val & RN5T618_POFFHIS_WDG)
  wdt->wdt_dev.bootstatus = WDIOF_CARDRESET;

 watchdog_set_drvdata(&wdt->wdt_dev, wdt);
 watchdog_init_timeout(&wdt->wdt_dev, timeout, dev);
 watchdog_set_nowayout(&wdt->wdt_dev, nowayout);

 platform_set_drvdata(pdev, wdt);

 return devm_watchdog_register_device(dev, &wdt->wdt_dev);
}

static struct platform_driver rn5t618_wdt_driver = {
 .probe = rn5t618_wdt_probe,
 .driver = {
  .name = DRIVER_NAME,
 },
};

module_platform_driver(rn5t618_wdt_driver);

MODULE_ALIAS("platform:rn5t618-wdt");
MODULE_AUTHOR("Beniamino Galvani ");
MODULE_DESCRIPTION("RN5T618 watchdog driver");
MODULE_LICENSE("GPL v2");