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linux-next/drivers/watchdog/da9063_wdt.c
Stefan Christ a74cab40b5 watchdog: da9063_wdt: don't trigger watchdog too fast
Triggering the watchdog faster than T_WDMIN=256ms leads to resets of the
DA9063 chip. The datasheet says that the watchdog must only be triggered
in the timeframe T_WDMIN to T_WDMAX. The T_WDMAX is configured in the
driver.

Signed-off-by: Stefan Christ <s.christ@phytec.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-07-17 21:02:42 +02:00

215 lines
5.4 KiB
C

/*
* Watchdog driver for DA9063 PMICs.
*
* Copyright(c) 2012 Dialog Semiconductor Ltd.
*
* Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/mfd/da9063/registers.h>
#include <linux/mfd/da9063/core.h>
#include <linux/regmap.h>
/*
* Watchdog selector to timeout in seconds.
* 0: WDT disabled;
* others: timeout = 2048 ms * 2^(TWDSCALE-1).
*/
static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
#define DA9063_TWDSCALE_DISABLE 0
#define DA9063_TWDSCALE_MIN 1
#define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
#define DA9063_WDG_TIMEOUT wdt_timeout[3]
#define DA9063_RESET_PROTECTION_MS 256
struct da9063_watchdog {
struct da9063 *da9063;
struct watchdog_device wdtdev;
};
static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
{
unsigned int i;
for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
if (wdt_timeout[i] >= secs)
return i;
}
return DA9063_TWDSCALE_MAX;
}
static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
{
return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
DA9063_TWDSCALE_MASK, regval);
}
static int da9063_wdt_start(struct watchdog_device *wdd)
{
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
unsigned int selector;
int ret;
selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
if (ret)
dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
ret);
return ret;
}
static int da9063_wdt_stop(struct watchdog_device *wdd)
{
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
if (ret)
dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
ret);
return ret;
}
static int da9063_wdt_ping(struct watchdog_device *wdd)
{
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
DA9063_WATCHDOG);
if (ret)
dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
ret);
return ret;
}
static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
unsigned int selector;
int ret;
selector = da9063_wdt_timeout_to_sel(timeout);
ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
if (ret)
dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
ret);
else
wdd->timeout = wdt_timeout[selector];
return ret;
}
static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
DA9063_SHUTDOWN);
if (ret)
dev_alert(wdt->da9063->dev, "Failed to shutdown (err = %d)\n",
ret);
return ret;
}
static const struct watchdog_info da9063_watchdog_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "DA9063 Watchdog",
};
static const struct watchdog_ops da9063_watchdog_ops = {
.owner = THIS_MODULE,
.start = da9063_wdt_start,
.stop = da9063_wdt_stop,
.ping = da9063_wdt_ping,
.set_timeout = da9063_wdt_set_timeout,
.restart = da9063_wdt_restart,
};
static int da9063_wdt_probe(struct platform_device *pdev)
{
int ret;
struct da9063 *da9063;
struct da9063_watchdog *wdt;
if (!pdev->dev.parent)
return -EINVAL;
da9063 = dev_get_drvdata(pdev->dev.parent);
if (!da9063)
return -EINVAL;
wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->da9063 = da9063;
wdt->wdtdev.info = &da9063_watchdog_info;
wdt->wdtdev.ops = &da9063_watchdog_ops;
wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
wdt->wdtdev.min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
wdt->wdtdev.parent = &pdev->dev;
wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
watchdog_set_restart_priority(&wdt->wdtdev, 128);
watchdog_set_drvdata(&wdt->wdtdev, wdt);
dev_set_drvdata(&pdev->dev, wdt);
ret = watchdog_register_device(&wdt->wdtdev);
if (ret)
return ret;
return 0;
}
static int da9063_wdt_remove(struct platform_device *pdev)
{
struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
watchdog_unregister_device(&wdt->wdtdev);
return 0;
}
static struct platform_driver da9063_wdt_driver = {
.probe = da9063_wdt_probe,
.remove = da9063_wdt_remove,
.driver = {
.name = DA9063_DRVNAME_WATCHDOG,
},
};
module_platform_driver(da9063_wdt_driver);
MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);