wm8350_wdt.c
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/*
* Watchdog driver for the wm8350
*
* Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.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
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/mfd/wm8350/core.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) ")");
static DEFINE_MUTEX(wdt_mutex);
static struct {
unsigned int time; /* Seconds */
u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */
} wm8350_wdt_cfgs[] = {
{ 1, 0x02 },
{ 2, 0x04 },
{ 4, 0x05 },
};
static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
int ret, i;
u16 reg;
for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
if (wm8350_wdt_cfgs[i].time == timeout)
break;
if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
return -EINVAL;
mutex_lock(&wdt_mutex);
wm8350_reg_unlock(wm8350);
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
reg &= ~WM8350_WDOG_TO_MASK;
reg |= wm8350_wdt_cfgs[i].val;
ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
wm8350_reg_lock(wm8350);
mutex_unlock(&wdt_mutex);
wdt_dev->timeout = timeout;
return ret;
}
static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
{
struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
int ret;
u16 reg;
mutex_lock(&wdt_mutex);
wm8350_reg_unlock(wm8350);
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
reg &= ~WM8350_WDOG_MODE_MASK;
reg |= 0x20;
ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
wm8350_reg_lock(wm8350);
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
{
struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
int ret;
u16 reg;
mutex_lock(&wdt_mutex);
wm8350_reg_unlock(wm8350);
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
reg &= ~WM8350_WDOG_MODE_MASK;
ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
wm8350_reg_lock(wm8350);
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm8350_wdt_ping(struct watchdog_device *wdt_dev)
{
struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
int ret;
u16 reg;
mutex_lock(&wdt_mutex);
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
mutex_unlock(&wdt_mutex);
return ret;
}
static const struct watchdog_info wm8350_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "WM8350 Watchdog",
};
static const struct watchdog_ops wm8350_wdt_ops = {
.owner = THIS_MODULE,
.start = wm8350_wdt_start,
.stop = wm8350_wdt_stop,
.ping = wm8350_wdt_ping,
.set_timeout = wm8350_wdt_set_timeout,
};
static struct watchdog_device wm8350_wdt = {
.info = &wm8350_wdt_info,
.ops = &wm8350_wdt_ops,
.timeout = 4,
.min_timeout = 1,
.max_timeout = 4,
};
static int wm8350_wdt_probe(struct platform_device *pdev)
{
struct wm8350 *wm8350 = platform_get_drvdata(pdev);
if (!wm8350) {
pr_err("No driver data supplied\n");
return -ENODEV;
}
watchdog_set_nowayout(&wm8350_wdt, nowayout);
watchdog_set_drvdata(&wm8350_wdt, wm8350);
wm8350_wdt.parent = &pdev->dev;
/* Default to 4s timeout */
wm8350_wdt_set_timeout(&wm8350_wdt, 4);
return watchdog_register_device(&wm8350_wdt);
}
static int wm8350_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&wm8350_wdt);
return 0;
}
static struct platform_driver wm8350_wdt_driver = {
.probe = wm8350_wdt_probe,
.remove = wm8350_wdt_remove,
.driver = {
.name = "wm8350-wdt",
},
};
module_platform_driver(wm8350_wdt_driver);
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM8350 Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-wdt");