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/*
* System monitoring driver for DA9055 PMICs.
*
* Copyright(c) 2012 Dialog Semiconductor Ltd.
*
* Author: David Dajun Chen <dchen@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/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/delay.h>
#include <linux/mfd/da9055/core.h>
#include <linux/mfd/da9055/reg.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#define DA9055_DEF_TIMEOUT 4
#define DA9055_TWDMIN 256
struct da9055_wdt_data {
struct watchdog_device wdt;
struct da9055 *da9055;
struct kref kref;
};
static const struct {
u8 reg_val;
int user_time; /* In seconds */
} da9055_wdt_maps[] = {
{ 0, 0 },
{ 1, 2 },
{ 2, 4 },
{ 3, 8 },
{ 4, 16 },
{ 5, 32 },
{ 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */
{ 6, 65 },
{ 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */
{ 7, 131 },
};
static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
struct da9055 *da9055 = driver_data->da9055;
int ret, i;
for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
if (da9055_wdt_maps[i].user_time == timeout)
break;
if (i == ARRAY_SIZE(da9055_wdt_maps))
ret = -EINVAL;
else
ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
DA9055_TWDSCALE_MASK,
da9055_wdt_maps[i].reg_val <<
DA9055_TWDSCALE_SHIFT);
if (ret < 0)
dev_err(da9055->dev,
"Failed to update timescale bit, %d\n", ret);
wdt_dev->timeout = timeout;
return ret;
}
static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
{
struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
struct da9055 *da9055 = driver_data->da9055;
int ret;
/*
* We have a minimum time for watchdog window called TWDMIN. A write
* to the watchdog before this elapsed time will cause an error.
*/
mdelay(DA9055_TWDMIN);
/* Reset the watchdog timer */
ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
DA9055_WATCHDOG_MASK, 1);
return ret;
}
static void da9055_wdt_release_resources(struct kref *r)
{
struct da9055_wdt_data *driver_data =
container_of(r, struct da9055_wdt_data, kref);
kfree(driver_data);
}
static void da9055_wdt_ref(struct watchdog_device *wdt_dev)
{
struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
kref_get(&driver_data->kref);
}
static void da9055_wdt_unref(struct watchdog_device *wdt_dev)
{
struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
kref_put(&driver_data->kref, da9055_wdt_release_resources);
}
static int da9055_wdt_start(struct watchdog_device *wdt_dev)
{
return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
}
static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
{
return da9055_wdt_set_timeout(wdt_dev, 0);
}
static struct watchdog_info da9055_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "DA9055 Watchdog",
};
static const struct watchdog_ops da9055_wdt_ops = {
.owner = THIS_MODULE,
.start = da9055_wdt_start,
.stop = da9055_wdt_stop,
.ping = da9055_wdt_ping,
.set_timeout = da9055_wdt_set_timeout,
.ref = da9055_wdt_ref,
.unref = da9055_wdt_unref,
};
static int da9055_wdt_probe(struct platform_device *pdev)
{
struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent);
struct da9055_wdt_data *driver_data;
struct watchdog_device *da9055_wdt;
int ret;
driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
GFP_KERNEL);
if (!driver_data) {
dev_err(da9055->dev, "Failed to allocate watchdog device\n");
return -ENOMEM;
}
driver_data->da9055 = da9055;
da9055_wdt = &driver_data->wdt;
da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
da9055_wdt->info = &da9055_wdt_info;
da9055_wdt->ops = &da9055_wdt_ops;
watchdog_set_nowayout(da9055_wdt, nowayout);
watchdog_set_drvdata(da9055_wdt, driver_data);
kref_init(&driver_data->kref);
ret = da9055_wdt_stop(da9055_wdt);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret);
goto err;
}
dev_set_drvdata(&pdev->dev, driver_data);
ret = watchdog_register_device(&driver_data->wdt);
if (ret != 0)
dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
ret);
err:
return ret;
}
static int da9055_wdt_remove(struct platform_device *pdev)
{
struct da9055_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
watchdog_unregister_device(&driver_data->wdt);
kref_put(&driver_data->kref, da9055_wdt_release_resources);
return 0;
}
static struct platform_driver da9055_wdt_driver = {
.probe = da9055_wdt_probe,
.remove = da9055_wdt_remove,
.driver = {
.name = "da9055-watchdog",
},
};
module_platform_driver(da9055_wdt_driver);
MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
MODULE_DESCRIPTION("DA9055 watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9055-watchdog");
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