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android_kernel_xiaomi_sm8350/drivers/watchdog/wm831x_wdt.c
Mark Brown 502a0106b2 [WATCHDOG] Add support for WM831x watchdog 
The WM831x series of devices provide a watchdog with configurable
behaviour on timer expiry.

Currently this driver support refreshes via a register or GPIO line and
autonomous refreshes from a hardware source (eg, a clock).

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2009-09-18 08:35:49 +00:00

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/*
* Watchdog driver for the wm831x PMICs
*
* Copyright (C) 2009 Wolfson Microelectronics
*
* 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/gpio.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/watchdog.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 wm831x_wdt_users;
static struct miscdevice wm831x_wdt_miscdev;
static int wm831x_wdt_expect_close;
static DEFINE_MUTEX(wdt_mutex);
static struct wm831x *wm831x;
static unsigned int update_gpio;
static unsigned int update_state;
/* We can't use the sub-second values here but they're included
* for completeness. */
static struct {
int time; /* Seconds */
u16 val; /* WDOG_TO value */
} wm831x_wdt_cfgs[] = {
{ 1, 2 },
{ 2, 3 },
{ 4, 4 },
{ 8, 5 },
{ 16, 6 },
{ 32, 7 },
{ 33, 7 }, /* Actually 32.768s so include both, others round down */
};
static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value)
{
int ret;
mutex_lock(&wdt_mutex);
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_TO_MASK, value);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm831x_wdt_start(struct wm831x *wm831x)
{
int ret;
mutex_lock(&wdt_mutex);
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_ENA, WM831X_WDOG_ENA);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm831x_wdt_stop(struct wm831x *wm831x)
{
int ret;
mutex_lock(&wdt_mutex);
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_ENA, 0);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm831x_wdt_kick(struct wm831x *wm831x)
{
int ret;
u16 reg;
mutex_lock(&wdt_mutex);
if (update_gpio) {
gpio_set_value_cansleep(update_gpio, update_state);
update_state = !update_state;
ret = 0;
goto out;
}
reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
if (!(reg & WM831X_WDOG_RST_SRC)) {
dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
ret = -EINVAL;
goto out;
}
reg |= WM831X_WDOG_RESET;
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
out:
mutex_unlock(&wdt_mutex);
return ret;
}
static int wm831x_wdt_open(struct inode *inode, struct file *file)
{
int ret;
if (!wm831x)
return -ENODEV;
if (test_and_set_bit(0, &wm831x_wdt_users))
return -EBUSY;
ret = wm831x_wdt_start(wm831x);
if (ret != 0)
return ret;
return nonseekable_open(inode, file);
}
static int wm831x_wdt_release(struct inode *inode, struct file *file)
{
if (wm831x_wdt_expect_close)
wm831x_wdt_stop(wm831x);
else {
dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n");
wm831x_wdt_kick(wm831x);
}
clear_bit(0, &wm831x_wdt_users);
return 0;
}
static ssize_t wm831x_wdt_write(struct file *file,
const char __user *data, size_t count,
loff_t *ppos)
{
size_t i;
if (count) {
wm831x_wdt_kick(wm831x);
if (!nowayout) {
/* In case it was set long ago */
wm831x_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')
wm831x_wdt_expect_close = 42;
}
}
}
return count;
}
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "WM831x Watchdog",
};
static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
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 = wm831x_wdt_start(wm831x);
if (options == WDIOS_ENABLECARD)
ret = wm831x_wdt_stop(wm831x);
break;
}
case WDIOC_KEEPALIVE:
ret = wm831x_wdt_kick(wm831x);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, p);
if (ret)
break;
if (time == 0) {
if (nowayout)
ret = -EINVAL;
else
wm831x_wdt_stop(wm831x);
break;
}
for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
if (wm831x_wdt_cfgs[i].time == time)
break;
if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
ret = -EINVAL;
else
ret = wm831x_wdt_set_timeout(wm831x,
wm831x_wdt_cfgs[i].val);
break;
case WDIOC_GETTIMEOUT:
reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
reg &= WM831X_WDOG_TO_MASK;
for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
if (wm831x_wdt_cfgs[i].val == reg)
break;
if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) {
dev_warn(wm831x->dev,
"Unknown watchdog configuration: %x\n", reg);
ret = -EINVAL;
} else
ret = put_user(wm831x_wdt_cfgs[i].time, p);
}
return ret;
}
static const struct file_operations wm831x_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wm831x_wdt_write,
.unlocked_ioctl = wm831x_wdt_ioctl,
.open = wm831x_wdt_open,
.release = wm831x_wdt_release,
};
static struct miscdevice wm831x_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wm831x_wdt_fops,
};
static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
{
struct wm831x_pdata *chip_pdata;
struct wm831x_watchdog_pdata *pdata;
int reg, ret;
wm831x = dev_get_drvdata(pdev->dev.parent);
ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
if (ret < 0) {
dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
ret);
goto err;
}
reg = ret;
if (reg & WM831X_WDOG_DEBUG)
dev_warn(wm831x->dev, "Watchdog is paused\n");
/* Apply any configuration */
if (pdev->dev.parent->platform_data) {
chip_pdata = pdev->dev.parent->platform_data;
pdata = chip_pdata->watchdog;
} else {
pdata = NULL;
}
if (pdata) {
reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
WM831X_WDOG_RST_SRC);
reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
if (pdata->update_gpio) {
ret = gpio_request(pdata->update_gpio,
"Watchdog update");
if (ret < 0) {
dev_err(wm831x->dev,
"Failed to request update GPIO: %d\n",
ret);
goto err;
}
ret = gpio_direction_output(pdata->update_gpio, 0);
if (ret != 0) {
dev_err(wm831x->dev,
"gpio_direction_output returned: %d\n",
ret);
goto err_gpio;
}
update_gpio = pdata->update_gpio;
/* Make sure the watchdog takes hardware updates */
reg |= WM831X_WDOG_RST_SRC;
}
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev,
"Failed to unlock security key: %d\n", ret);
goto err_gpio;
}
}
wm831x_wdt_miscdev.parent = &pdev->dev;
ret = misc_register(&wm831x_wdt_miscdev);
if (ret != 0) {
dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret);
goto err_gpio;
}
return 0;
err_gpio:
if (update_gpio) {
gpio_free(update_gpio);
update_gpio = 0;
}
err:
return ret;
}
static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
{
if (update_gpio) {
gpio_free(update_gpio);
update_gpio = 0;
}
misc_deregister(&wm831x_wdt_miscdev);
return 0;
}
static struct platform_driver wm831x_wdt_driver = {
.probe = wm831x_wdt_probe,
.remove = __devexit_p(wm831x_wdt_remove),
.driver = {
.name = "wm831x-watchdog",
},
};
static int __init wm831x_wdt_init(void)
{
return platform_driver_register(&wm831x_wdt_driver);
}
module_init(wm831x_wdt_init);
static void __exit wm831x_wdt_exit(void)
{
platform_driver_unregister(&wm831x_wdt_driver);
}
module_exit(wm831x_wdt_exit);
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-watchdog");
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