drivers/watchdog/it8712f_wdt.c - kernel/bruno - Git at Google

 /*
  *	IT8712F "Smart Guardian" Watchdog support
  *
  *	Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
  *
  *	Based on info and code taken from:
  *
  *	drivers/char/watchdog/scx200_wdt.c
  *	drivers/hwmon/it87.c
  *	IT8712F EC-LPC I/O Preliminary Specification 0.8.2
  *	IT8712F EC-LPC I/O Preliminary Specification 0.9.3
  *
  *	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.
  *
  *	The author(s) of this software shall not be held liable for damages
  *	of any nature resulting due to the use of this software. This
  *	software is provided AS-IS with no warranties.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
 #include <linux/fs.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ioport.h>

 #define DEBUG
 #define NAME "it8712f_wdt"

 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
 MODULE_LICENSE("GPL");

 static int max_units = 255;
 static int margin = 60;		/* in seconds */
 module_param(margin, int, 0);
 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

 static unsigned long wdt_open;
 static unsigned expect_close;
 static unsigned char revision;

 /* Dog Food address - We use the game port address */
 static unsigned short address;

 #define	REG		0x2e	/* The register to read/write */
 #define	VAL		0x2f	/* The value to read/write */

 #define	LDN		0x07	/* Register: Logical device select */
 #define	DEVID		0x20	/* Register: Device ID */
 #define	DEVREV		0x22	/* Register: Device Revision */
 #define ACT_REG		0x30	/* LDN Register: Activation */
 #define BASE_REG	0x60	/* LDN Register: Base address */

 #define IT8712F_DEVID	0x8712

 #define LDN_GPIO	0x07	/* GPIO and Watch Dog Timer */
 #define LDN_GAME	0x09	/* Game Port */

 #define WDT_CONTROL	0x71	/* WDT Register: Control */
 #define WDT_CONFIG	0x72	/* WDT Register: Configuration */
 #define WDT_TIMEOUT	0x73	/* WDT Register: Timeout Value */

 #define WDT_RESET_GAME	0x10	/* Reset timer on read or write to game port */
 #define WDT_RESET_KBD	0x20	/* Reset timer on keyboard interrupt */
 #define WDT_RESET_MOUSE	0x40	/* Reset timer on mouse interrupt */
 #define WDT_RESET_CIR	0x80	/* Reset timer on consumer IR interrupt */

 #define WDT_UNIT_SEC	0x80	/* If 0 in MINUTES */

 #define WDT_OUT_PWROK	0x10	/* Pulse PWROK on timeout */
 #define WDT_OUT_KRST	0x40	/* Pulse reset on timeout */

 static int wdt_control_reg = WDT_RESET_GAME;
 module_param(wdt_control_reg, int, 0);
 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
 		"register. The default WDT_RESET_GAME resets the timer on "
 		"game port reads that this driver generates. You can also "
 		"use KBD, MOUSE or CIR if you have some external way to "
 		"generate those interrupts.");

 static int superio_inb(int reg)
 {
 	outb(reg, REG);
 	return inb(VAL);
 }

 static void superio_outb(int val, int reg)
 {
 	outb(reg, REG);
 	outb(val, VAL);
 }

 static int superio_inw(int reg)
 {
 	int val;
 	outb(reg++, REG);
 	val = inb(VAL) << 8;
 	outb(reg, REG);
 	val |= inb(VAL);
 	return val;
 }

 static inline void superio_select(int ldn)
 {
 	outb(LDN, REG);
 	outb(ldn, VAL);
 }

 static inline int superio_enter(void)
 {
 	/*
 	 * Try to reserve REG and REG + 1 for exclusive access.
 	 */
 	if (!request_muxed_region(REG, 2, NAME))
 		return -EBUSY;

 	outb(0x87, REG);
 	outb(0x01, REG);
 	outb(0x55, REG);
 	outb(0x55, REG);
 	return 0;
 }

 static inline void superio_exit(void)
 {
 	outb(0x02, REG);
 	outb(0x02, VAL);
 	release_region(REG, 2);
 }

 static inline void it8712f_wdt_ping(void)
 {
 	if (wdt_control_reg & WDT_RESET_GAME)
 		inb(address);
 }

 static void it8712f_wdt_update_margin(void)
 {
 	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 	int units = margin;

 	/* Switch to minutes precision if the configured margin
 	 * value does not fit within the register width.
 	 */
 	if (units <= max_units) {
 		config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 		pr_info("timer margin %d seconds\n", units);
 	} else {
 		units /= 60;
 		pr_info("timer margin %d minutes\n", units);
 	}
 	superio_outb(config, WDT_CONFIG);

 	if (revision >= 0x08)
 		superio_outb(units >> 8, WDT_TIMEOUT + 1);
 	superio_outb(units, WDT_TIMEOUT);
 }

 static int it8712f_wdt_get_status(void)
 {
 	if (superio_inb(WDT_CONTROL) & 0x01)
 		return WDIOF_CARDRESET;
 	else
 		return 0;
 }

 static int it8712f_wdt_enable(void)
 {
 	int ret = superio_enter();
 	if (ret)
 		return ret;

 	pr_debug("enabling watchdog timer\n");
 	superio_select(LDN_GPIO);

 	superio_outb(wdt_control_reg, WDT_CONTROL);

 	it8712f_wdt_update_margin();

 	superio_exit();

 	it8712f_wdt_ping();

 	return 0;
 }

 static int it8712f_wdt_disable(void)
 {
 	int ret = superio_enter();
 	if (ret)
 		return ret;

 	pr_debug("disabling watchdog timer\n");
 	superio_select(LDN_GPIO);

 	superio_outb(0, WDT_CONFIG);
 	superio_outb(0, WDT_CONTROL);
 	if (revision >= 0x08)
 		superio_outb(0, WDT_TIMEOUT + 1);
 	superio_outb(0, WDT_TIMEOUT);

 	superio_exit();
 	return 0;
 }

 static int it8712f_wdt_notify(struct notifier_block *this,
 		    unsigned long code, void *unused)
 {
 	if (code == SYS_HALT || code == SYS_POWER_OFF)
 		if (!nowayout)
 			it8712f_wdt_disable();

 	return NOTIFY_DONE;
 }

 static struct notifier_block it8712f_wdt_notifier = {
 	.notifier_call = it8712f_wdt_notify,
 };

 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
 					size_t len, loff_t *ppos)
 {
 	/* check for a magic close character */
 	if (len) {
 		size_t i;

 		it8712f_wdt_ping();

 		expect_close = 0;
 		for (i = 0; i < len; ++i) {
 			char c;
 			if (get_user(c, data + i))
 				return -EFAULT;
 			if (c == 'V')
 				expect_close = 42;
 		}
 	}

 	return len;
 }

 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 							unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static const struct watchdog_info ident = {
 		.identity = "IT8712F Watchdog",
 		.firmware_version = 1,
 		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 						WDIOF_MAGICCLOSE,
 	};
 	int value;
 	int ret;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		if (copy_to_user(argp, &ident, sizeof(ident)))
 			return -EFAULT;
 		return 0;
 	case WDIOC_GETSTATUS:
 		ret = superio_enter();
 		if (ret)
 			return ret;
 		superio_select(LDN_GPIO);

 		value = it8712f_wdt_get_status();

 		superio_exit();

 		return put_user(value, p);
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);
 	case WDIOC_KEEPALIVE:
 		it8712f_wdt_ping();
 		return 0;
 	case WDIOC_SETTIMEOUT:
 		if (get_user(value, p))
 			return -EFAULT;
 		if (value < 1)
 			return -EINVAL;
 		if (value > (max_units * 60))
 			return -EINVAL;
 		margin = value;
 		ret = superio_enter();
 		if (ret)
 			return ret;
 		superio_select(LDN_GPIO);

 		it8712f_wdt_update_margin();

 		superio_exit();
 		it8712f_wdt_ping();
 		/* Fall through */
 	case WDIOC_GETTIMEOUT:
 		if (put_user(margin, p))
 			return -EFAULT;
 		return 0;
 	default:
 		return -ENOTTY;
 	}
 }

 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 {
 	int ret;
 	/* only allow one at a time */
 	if (test_and_set_bit(0, &wdt_open))
 		return -EBUSY;

 	ret = it8712f_wdt_enable();
 	if (ret)
 		return ret;
 	return nonseekable_open(inode, file);
 }

 static int it8712f_wdt_release(struct inode *inode, struct file *file)
 {
 	if (expect_close != 42) {
 		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
 	} else if (!nowayout) {
 		if (it8712f_wdt_disable())
 			pr_warn("Watchdog disable failed\n");
 	}
 	expect_close = 0;
 	clear_bit(0, &wdt_open);

 	return 0;
 }

 static const struct file_operations it8712f_wdt_fops = {
 	.owner = THIS_MODULE,
 	.llseek = no_llseek,
 	.write = it8712f_wdt_write,
 	.unlocked_ioctl = it8712f_wdt_ioctl,
 	.open = it8712f_wdt_open,
 	.release = it8712f_wdt_release,
 };

 static struct miscdevice it8712f_wdt_miscdev = {
 	.minor = WATCHDOG_MINOR,
 	.name = "watchdog",
 	.fops = &it8712f_wdt_fops,
 };

 static int __init it8712f_wdt_find(unsigned short *address)
 {
 	int err = -ENODEV;
 	int chip_type;
 	int ret = superio_enter();
 	if (ret)
 		return ret;

 	chip_type = superio_inw(DEVID);
 	if (chip_type != IT8712F_DEVID)
 		goto exit;

 	superio_select(LDN_GAME);
 	superio_outb(1, ACT_REG);
 	if (!(superio_inb(ACT_REG) & 0x01)) {
 		pr_err("Device not activated, skipping\n");
 		goto exit;
 	}

 	*address = superio_inw(BASE_REG);
 	if (*address == 0) {
 		pr_err("Base address not set, skipping\n");
 		goto exit;
 	}

 	err = 0;
 	revision = superio_inb(DEVREV) & 0x0f;

 	/* Later revisions have 16-bit values per datasheet 0.9.1 */
 	if (revision >= 0x08)
 		max_units = 65535;

 	if (margin > (max_units * 60))
 		margin = (max_units * 60);

 	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
 		chip_type, revision, *address);

 exit:
 	superio_exit();
 	return err;
 }

 static int __init it8712f_wdt_init(void)
 {
 	int err = 0;

 	if (it8712f_wdt_find(&address))
 		return -ENODEV;

 	if (!request_region(address, 1, "IT8712F Watchdog")) {
 		pr_warn("watchdog I/O region busy\n");
 		return -EBUSY;
 	}

 	err = it8712f_wdt_disable();
 	if (err) {
 		pr_err("unable to disable watchdog timer\n");
 		goto out;
 	}

 	err = register_reboot_notifier(&it8712f_wdt_notifier);
 	if (err) {
 		pr_err("unable to register reboot notifier\n");
 		goto out;
 	}

 	err = misc_register(&it8712f_wdt_miscdev);
 	if (err) {
 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 		       WATCHDOG_MINOR, err);
 		goto reboot_out;
 	}

 	return 0;


 reboot_out:
 	unregister_reboot_notifier(&it8712f_wdt_notifier);
 out:
 	release_region(address, 1);
 	return err;
 }

 static void __exit it8712f_wdt_exit(void)
 {
 	misc_deregister(&it8712f_wdt_miscdev);
 	unregister_reboot_notifier(&it8712f_wdt_notifier);
 	release_region(address, 1);
 }

 module_init(it8712f_wdt_init);
 module_exit(it8712f_wdt_exit);
	/*
	* IT8712F "Smart Guardian" Watchdog support
	*
	* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
	*
	* Based on info and code taken from:
	*
	* drivers/char/watchdog/scx200_wdt.c
	* drivers/hwmon/it87.c
	* IT8712F EC-LPC I/O Preliminary Specification 0.8.2
	* IT8712F EC-LPC I/O Preliminary Specification 0.9.3
	*
	* 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.
	*
	* The author(s) of this software shall not be held liable for damages
	* of any nature resulting due to the use of this software. This
	* software is provided AS-IS with no warranties.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/init.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/notifier.h>
	#include <linux/reboot.h>
	#include <linux/fs.h>
	#include <linux/spinlock.h>
	#include <linux/uaccess.h>
	#include <linux/io.h>
	#include <linux/ioport.h>

	#define DEBUG
	#define NAME "it8712f_wdt"

	MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
	MODULE_DESCRIPTION("IT8712F Watchdog Driver");
	MODULE_LICENSE("GPL");

	static int max_units = 255;
	static int margin = 60; /* in seconds */
	module_param(margin, int, 0);
	MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

	static bool nowayout = WATCHDOG_NOWAYOUT;
	module_param(nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

	static unsigned long wdt_open;
	static unsigned expect_close;
	static unsigned char revision;

	/* Dog Food address - We use the game port address */
	static unsigned short address;

	#define REG 0x2e /* The register to read/write */
	#define VAL 0x2f /* The value to read/write */

	#define LDN 0x07 /* Register: Logical device select */
	#define DEVID 0x20 /* Register: Device ID */
	#define DEVREV 0x22 /* Register: Device Revision */
	#define ACT_REG 0x30 /* LDN Register: Activation */
	#define BASE_REG 0x60 /* LDN Register: Base address */

	#define IT8712F_DEVID 0x8712

	#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
	#define LDN_GAME 0x09 /* Game Port */

	#define WDT_CONTROL 0x71 /* WDT Register: Control */
	#define WDT_CONFIG 0x72 /* WDT Register: Configuration */
	#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */

	#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
	#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
	#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
	#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */

	#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */

	#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
	#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */

	static int wdt_control_reg = WDT_RESET_GAME;
	module_param(wdt_control_reg, int, 0);
	MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
	"register. The default WDT_RESET_GAME resets the timer on "
	"game port reads that this driver generates. You can also "
	"use KBD, MOUSE or CIR if you have some external way to "
	"generate those interrupts.");

	static int superio_inb(int reg)
	{
	outb(reg, REG);
	return inb(VAL);
	}

	static void superio_outb(int val, int reg)
	{
	outb(reg, REG);
	outb(val, VAL);
	}

	static int superio_inw(int reg)
	{
	int val;
	outb(reg++, REG);
	val = inb(VAL) << 8;
	outb(reg, REG);
	val \|= inb(VAL);
	return val;
	}

	static inline void superio_select(int ldn)
	{
	outb(LDN, REG);
	outb(ldn, VAL);
	}

	static inline int superio_enter(void)
	{
	/*
	* Try to reserve REG and REG + 1 for exclusive access.
	*/
	if (!request_muxed_region(REG, 2, NAME))
	return -EBUSY;

	outb(0x87, REG);
	outb(0x01, REG);
	outb(0x55, REG);
	outb(0x55, REG);
	return 0;
	}

	static inline void superio_exit(void)
	{
	outb(0x02, REG);
	outb(0x02, VAL);
	release_region(REG, 2);
	}

	static inline void it8712f_wdt_ping(void)
	{
	if (wdt_control_reg & WDT_RESET_GAME)
	inb(address);
	}

	static void it8712f_wdt_update_margin(void)
	{
	int config = WDT_OUT_KRST \| WDT_OUT_PWROK;
	int units = margin;

	/* Switch to minutes precision if the configured margin
	* value does not fit within the register width.
	*/
	if (units <= max_units) {
	config \|= WDT_UNIT_SEC; /* else UNIT is MINUTES */
	pr_info("timer margin %d seconds\n", units);
	} else {
	units /= 60;
	pr_info("timer margin %d minutes\n", units);
	}
	superio_outb(config, WDT_CONFIG);

	if (revision >= 0x08)
	superio_outb(units >> 8, WDT_TIMEOUT + 1);
	superio_outb(units, WDT_TIMEOUT);
	}

	static int it8712f_wdt_get_status(void)
	{
	if (superio_inb(WDT_CONTROL) & 0x01)
	return WDIOF_CARDRESET;
	else
	return 0;
	}

	static int it8712f_wdt_enable(void)
	{
	int ret = superio_enter();
	if (ret)
	return ret;

	pr_debug("enabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(wdt_control_reg, WDT_CONTROL);

	it8712f_wdt_update_margin();

	superio_exit();

	it8712f_wdt_ping();

	return 0;
	}

	static int it8712f_wdt_disable(void)
	{
	int ret = superio_enter();
	if (ret)
	return ret;

	pr_debug("disabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(0, WDT_CONFIG);
	superio_outb(0, WDT_CONTROL);
	if (revision >= 0x08)
	superio_outb(0, WDT_TIMEOUT + 1);
	superio_outb(0, WDT_TIMEOUT);

	superio_exit();
	return 0;
	}

	static int it8712f_wdt_notify(struct notifier_block *this,
	unsigned long code, void *unused)
	{
	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	if (!nowayout)
	it8712f_wdt_disable();

	return NOTIFY_DONE;
	}

	static struct notifier_block it8712f_wdt_notifier = {
	.notifier_call = it8712f_wdt_notify,
	};

	static ssize_t it8712f_wdt_write(struct file file, const char __user data,
	size_t len, loff_t *ppos)
	{
	/* check for a magic close character */
	if (len) {
	size_t i;

	it8712f_wdt_ping();

	expect_close = 0;
	for (i = 0; i < len; ++i) {
	char c;
	if (get_user(c, data + i))
	return -EFAULT;
	if (c == 'V')
	expect_close = 42;
	}
	}

	return len;
	}

	static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
	.identity = "IT8712F Watchdog",
	.firmware_version = 1,
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};
	int value;
	int ret;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	if (copy_to_user(argp, &ident, sizeof(ident)))
	return -EFAULT;
	return 0;
	case WDIOC_GETSTATUS:
	ret = superio_enter();
	if (ret)
	return ret;
	superio_select(LDN_GPIO);

	value = it8712f_wdt_get_status();

	superio_exit();

	return put_user(value, p);
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);
	case WDIOC_KEEPALIVE:
	it8712f_wdt_ping();
	return 0;
	case WDIOC_SETTIMEOUT:
	if (get_user(value, p))
	return -EFAULT;
	if (value < 1)
	return -EINVAL;
	if (value > (max_units * 60))
	return -EINVAL;
	margin = value;
	ret = superio_enter();
	if (ret)
	return ret;
	superio_select(LDN_GPIO);

	it8712f_wdt_update_margin();

	superio_exit();
	it8712f_wdt_ping();
	/* Fall through */
	case WDIOC_GETTIMEOUT:
	if (put_user(margin, p))
	return -EFAULT;
	return 0;
	default:
	return -ENOTTY;
	}
	}

	static int it8712f_wdt_open(struct inode inode, struct file file)
	{
	int ret;
	/* only allow one at a time */
	if (test_and_set_bit(0, &wdt_open))
	return -EBUSY;

	ret = it8712f_wdt_enable();
	if (ret)
	return ret;
	return nonseekable_open(inode, file);
	}

	static int it8712f_wdt_release(struct inode inode, struct file file)
	{
	if (expect_close != 42) {
	pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	} else if (!nowayout) {
	if (it8712f_wdt_disable())
	pr_warn("Watchdog disable failed\n");
	}
	expect_close = 0;
	clear_bit(0, &wdt_open);

	return 0;
	}

	static const struct file_operations it8712f_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = it8712f_wdt_write,
	.unlocked_ioctl = it8712f_wdt_ioctl,
	.open = it8712f_wdt_open,
	.release = it8712f_wdt_release,
	};

	static struct miscdevice it8712f_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &it8712f_wdt_fops,
	};

	static int __init it8712f_wdt_find(unsigned short *address)
	{
	int err = -ENODEV;
	int chip_type;
	int ret = superio_enter();
	if (ret)
	return ret;

	chip_type = superio_inw(DEVID);
	if (chip_type != IT8712F_DEVID)
	goto exit;

	superio_select(LDN_GAME);
	superio_outb(1, ACT_REG);
	if (!(superio_inb(ACT_REG) & 0x01)) {
	pr_err("Device not activated, skipping\n");
	goto exit;
	}

	*address = superio_inw(BASE_REG);
	if (*address == 0) {
	pr_err("Base address not set, skipping\n");
	goto exit;
	}

	err = 0;
	revision = superio_inb(DEVREV) & 0x0f;

	/* Later revisions have 16-bit values per datasheet 0.9.1 */
	if (revision >= 0x08)
	max_units = 65535;

	if (margin > (max_units * 60))
	margin = (max_units * 60);

	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
	chip_type, revision, *address);

	exit:
	superio_exit();
	return err;
	}

	static int __init it8712f_wdt_init(void)
	{
	int err = 0;

	if (it8712f_wdt_find(&address))
	return -ENODEV;

	if (!request_region(address, 1, "IT8712F Watchdog")) {
	pr_warn("watchdog I/O region busy\n");
	return -EBUSY;
	}

	err = it8712f_wdt_disable();
	if (err) {
	pr_err("unable to disable watchdog timer\n");
	goto out;
	}

	err = register_reboot_notifier(&it8712f_wdt_notifier);
	if (err) {
	pr_err("unable to register reboot notifier\n");
	goto out;
	}

	err = misc_register(&it8712f_wdt_miscdev);
	if (err) {
	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	WATCHDOG_MINOR, err);
	goto reboot_out;
	}

	return 0;


	reboot_out:
	unregister_reboot_notifier(&it8712f_wdt_notifier);
	out:
	release_region(address, 1);
	return err;
	}

	static void __exit it8712f_wdt_exit(void)
	{
	misc_deregister(&it8712f_wdt_miscdev);
	unregister_reboot_notifier(&it8712f_wdt_notifier);
	release_region(address, 1);
	}

	module_init(it8712f_wdt_init);
	module_exit(it8712f_wdt_exit);