rn5t618_wdt.c
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/*
* Watchdog driver for Ricoh RN5T618 PMIC
*
* Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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 struct watchdog_info rn5t618_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.identity = DRIVER_NAME,
};
static 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 rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
struct rn5t618_wdt *wdt;
int min_timeout, max_timeout;
wdt = devm_kzalloc(&pdev->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 = &pdev->dev;
watchdog_set_drvdata(&wdt->wdt_dev, wdt);
watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev);
watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
platform_set_drvdata(pdev, wdt);
return watchdog_register_device(&wdt->wdt_dev);
}
static int rn5t618_wdt_remove(struct platform_device *pdev)
{
struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&wdt->wdt_dev);
return 0;
}
static struct platform_driver rn5t618_wdt_driver = {
.probe = rn5t618_wdt_probe,
.remove = rn5t618_wdt_remove,
.driver = {
.name = DRIVER_NAME,
},
};
module_platform_driver(rn5t618_wdt_driver);
MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("RN5T618 watchdog driver");
MODULE_LICENSE("GPL v2");