/*
* 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
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/mfd/wm8350/core.h>
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned long wm8350_wdt_users;
static struct miscdevice wm8350_wdt_miscdev;
static int wm8350_wdt_expect_close;
static DEFINE_MUTEX(wdt_mutex);
static struct {
int time; /* Seconds */
u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */
} wm8350_wdt_cfgs[] = {
{ 1, 0x02 },
{ 2, 0x04 },
{ 4, 0x05 },
};
static struct wm8350 *get_wm8350(void)
{
return dev_get_drvdata(wm8350_wdt_miscdev.parent);
}
static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value)
{
int ret;
u16 reg;
mutex_lock(&wdt_mutex);
wm8350_reg_unlock(wm8350);
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
reg &= ~WM8350_WDOG_TO_MASK;
reg |= value;
ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
wm8350_reg_lock(wm8350);
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm8350_wdt_start(struct wm8350 *wm8350)
{
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 wm8350 *wm8350)
{
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_kick(struct wm8350 *wm8350)
{
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 int wm8350_wdt_open(struct inode *inode, struct file *file)
{
struct wm8350 *wm8350 = get_wm8350();
int ret;
if (!wm8350)
return -ENODEV;
if (test_and_set_bit(0, &wm8350_wdt_users))
return -EBUSY;
ret = wm8350_wdt_start(wm8350);
if (ret != 0)
return ret;
return nonseekable_open(inode, file);
}
static int wm8350_wdt_release(struct inode *inode, struct file *file)
{
struct wm8350 *wm8350 = get_wm8350();
if (wm8350_wdt_expect_close)
wm8350_wdt_stop(wm8350);
else {
dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n");
wm8350_wdt_kick(wm8350);
}
clear_bit(0, &wm8350_wdt_users);
return 0;
}
static ssize_t wm8350_wdt_write(struct file *file,
const char __user *data, size_t count,
loff_t *ppos)
{
struct wm8350 *wm8350 = get_wm8350();
size_t i;
if (count) {
wm8350_wdt_kick(wm8350);
if (!nowayout) {
/* In case it was set long ago */
wm8350_wdt_expect_close = 0;
/* scan to see whether or not we got the magic
character */
for (i = 0; i != count; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
wm8350_wdt_expect_close = 42;
}
}
}
return count;
}
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "WM8350 Watchdog",
};
static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct wm8350 *wm8350 = get_wm8350();
int ret = -ENOTTY, time, i;
void __user *argp = (void __user *)arg;
int __user *p = argp;
u16 reg;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, p);
break;
case WDIOC_SETOPTIONS:
{
int options;
if (get_user(options, p))
return -EFAULT;
ret = -EINVAL;
/* Setting both simultaneously means at least one must fail */
if (options == WDIOS_DISABLECARD)
ret = wm8350_wdt_start(wm8350);
if (options == WDIOS_ENABLECARD)
ret = wm8350_wdt_stop(wm8350);
break;
}
case WDIOC_KEEPALIVE:
ret = wm8350_wdt_kick(wm8350);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, p);
if (ret)
break;
if (time == 0) {
if (nowayout)
ret = -EINVAL;
else
wm8350_wdt_stop(wm8350);
break;
}
for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
if (wm8350_wdt_cfgs[i].time == time)
break;
if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
ret = -EINVAL;
else
ret = wm8350_wdt_set_timeout(wm8350,
wm8350_wdt_cfgs[i].val);
break;
case WDIOC_GETTIMEOUT:
reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
reg &= WM8350_WDOG_TO_MASK;
for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
if (wm8350_wdt_cfgs[i].val == reg)
break;
if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) {
dev_warn(wm8350->dev,
"Unknown watchdog configuration: %x\n", reg);
ret = -EINVAL;
} else
ret = put_user(wm8350_wdt_cfgs[i].time, p);
}
return ret;
}
static const struct file_operations wm8350_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wm8350_wdt_write,
.unlocked_ioctl = wm8350_wdt_ioctl,
.open = wm8350_wdt_open,
.release = wm8350_wdt_release,
};
static struct miscdevice wm8350_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wm8350_wdt_fops,
};
static int __devinit 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;
}
/* Default to 4s timeout */
wm8350_wdt_set_timeout(wm8350, 0x05);
wm8350_wdt_miscdev.parent = &pdev->dev;
return misc_register(&wm8350_wdt_miscdev);
}
static int __devexit wm8350_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&wm8350_wdt_miscdev);
return 0;
}
static struct platform_driver wm8350_wdt_driver = {
.probe = wm8350_wdt_probe,
.remove = __devexit_p(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");
