drivers/watchdog/wm8350_wdt.c - maze/linux - Git at Google

 /*
  * 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_stop(wm8350);

 		if (options == WDIOS_ENABLECARD)
 			ret = wm8350_wdt_start(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");
	/*
	* 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_stop(wm8350);

	if (options == WDIOS_ENABLECARD)
	ret = wm8350_wdt_start(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");