[deliverable/linux.git] / drivers / watchdog / it8712f_wdt.c

/*
 *	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);
Commit	Line	Data
	1	/*
	2	* IT8712F "Smart Guardian" Watchdog support
	3	*
	4	* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
	5	*
	6	* Based on info and code taken from:
	7	*
	8	* drivers/char/watchdog/scx200_wdt.c
	9	* drivers/hwmon/it87.c
	10	* IT8712F EC-LPC I/O Preliminary Specification 0.8.2
	11	* IT8712F EC-LPC I/O Preliminary Specification 0.9.3
	12	*
	13	* This program is free software; you can redistribute it and/or
	14	* modify it under the terms of the GNU General Public License as
	15	* published by the Free Software Foundation; either version 2 of the
	16	* License, or (at your option) any later version.
	17	*
	18	* The author(s) of this software shall not be held liable for damages
	19	* of any nature resulting due to the use of this software. This
	20	* software is provided AS-IS with no warranties.
	21	*/
	22
	23	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	24
	25	#include <linux/module.h>
	26	#include <linux/moduleparam.h>
	27	#include <linux/init.h>
	28	#include <linux/miscdevice.h>
	29	#include <linux/watchdog.h>
	30	#include <linux/notifier.h>
	31	#include <linux/reboot.h>
	32	#include <linux/fs.h>
	33	#include <linux/spinlock.h>
	34	#include <linux/uaccess.h>
	35	#include <linux/io.h>
	36	#include <linux/ioport.h>
	37
	38	#define DEBUG
	39	#define NAME "it8712f_wdt"
	40
	41	MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
	42	MODULE_DESCRIPTION("IT8712F Watchdog Driver");
	43	MODULE_LICENSE("GPL");
	44
	45	static int max_units = 255;
	46	static int margin = 60; /* in seconds */
	47	module_param(margin, int, 0);
	48	MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
	49
	50	static bool nowayout = WATCHDOG_NOWAYOUT;
	51	module_param(nowayout, bool, 0);
	52	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
	53
	54	static unsigned long wdt_open;
	55	static unsigned expect_close;
	56	static unsigned char revision;
	57
	58	/* Dog Food address - We use the game port address */
	59	static unsigned short address;
	60
	61	#define REG 0x2e /* The register to read/write */
	62	#define VAL 0x2f /* The value to read/write */
	63
	64	#define LDN 0x07 /* Register: Logical device select */
	65	#define DEVID 0x20 /* Register: Device ID */
	66	#define DEVREV 0x22 /* Register: Device Revision */
	67	#define ACT_REG 0x30 /* LDN Register: Activation */
	68	#define BASE_REG 0x60 /* LDN Register: Base address */
	69
	70	#define IT8712F_DEVID 0x8712
	71
	72	#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
	73	#define LDN_GAME 0x09 /* Game Port */
	74
	75	#define WDT_CONTROL 0x71 /* WDT Register: Control */
	76	#define WDT_CONFIG 0x72 /* WDT Register: Configuration */
	77	#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
	78
	79	#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
	80	#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
	81	#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
	82	#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */
	83
	84	#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
	85
	86	#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
	87	#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */
	88
	89	static int wdt_control_reg = WDT_RESET_GAME;
	90	module_param(wdt_control_reg, int, 0);
	91	MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
	92	"register. The default WDT_RESET_GAME resets the timer on "
	93	"game port reads that this driver generates. You can also "
	94	"use KBD, MOUSE or CIR if you have some external way to "
	95	"generate those interrupts.");
	96
	97	static int superio_inb(int reg)
	98	{
	99	outb(reg, REG);
	100	return inb(VAL);
	101	}
	102
	103	static void superio_outb(int val, int reg)
	104	{
	105	outb(reg, REG);
	106	outb(val, VAL);
	107	}
	108
	109	static int superio_inw(int reg)
	110	{
	111	int val;
	112	outb(reg++, REG);
	113	val = inb(VAL) << 8;
	114	outb(reg, REG);
	115	val \|= inb(VAL);
	116	return val;
	117	}
	118
	119	static inline void superio_select(int ldn)
	120	{
	121	outb(LDN, REG);
	122	outb(ldn, VAL);
	123	}
	124
	125	static inline int superio_enter(void)
	126	{
	127	/*
	128	* Try to reserve REG and REG + 1 for exclusive access.
	129	*/
	130	if (!request_muxed_region(REG, 2, NAME))
	131	return -EBUSY;
	132
	133	outb(0x87, REG);
	134	outb(0x01, REG);
	135	outb(0x55, REG);
	136	outb(0x55, REG);
	137	return 0;
	138	}
	139
	140	static inline void superio_exit(void)
	141	{
	142	outb(0x02, REG);
	143	outb(0x02, VAL);
	144	release_region(REG, 2);
	145	}
	146
	147	static inline void it8712f_wdt_ping(void)
	148	{
	149	if (wdt_control_reg & WDT_RESET_GAME)
	150	inb(address);
	151	}
	152
	153	static void it8712f_wdt_update_margin(void)
	154	{
	155	int config = WDT_OUT_KRST \| WDT_OUT_PWROK;
	156	int units = margin;
	157
	158	/* Switch to minutes precision if the configured margin
	159	* value does not fit within the register width.
	160	*/
	161	if (units <= max_units) {
	162	config \|= WDT_UNIT_SEC; /* else UNIT is MINUTES */
	163	pr_info("timer margin %d seconds\n", units);
	164	} else {
	165	units /= 60;
	166	pr_info("timer margin %d minutes\n", units);
	167	}
	168	superio_outb(config, WDT_CONFIG);
	169
	170	if (revision >= 0x08)
	171	superio_outb(units >> 8, WDT_TIMEOUT + 1);
	172	superio_outb(units, WDT_TIMEOUT);
	173	}
	174
	175	static int it8712f_wdt_get_status(void)
	176	{
	177	if (superio_inb(WDT_CONTROL) & 0x01)
	178	return WDIOF_CARDRESET;
	179	else
	180	return 0;
	181	}
	182
	183	static int it8712f_wdt_enable(void)
	184	{
	185	int ret = superio_enter();
	186	if (ret)
	187	return ret;
	188
	189	pr_debug("enabling watchdog timer\n");
	190	superio_select(LDN_GPIO);
	191
	192	superio_outb(wdt_control_reg, WDT_CONTROL);
	193
	194	it8712f_wdt_update_margin();
	195
	196	superio_exit();
	197
	198	it8712f_wdt_ping();
	199
	200	return 0;
	201	}
	202
	203	static int it8712f_wdt_disable(void)
	204	{
	205	int ret = superio_enter();
	206	if (ret)
	207	return ret;
	208
	209	pr_debug("disabling watchdog timer\n");
	210	superio_select(LDN_GPIO);
	211
	212	superio_outb(0, WDT_CONFIG);
	213	superio_outb(0, WDT_CONTROL);
	214	if (revision >= 0x08)
	215	superio_outb(0, WDT_TIMEOUT + 1);
	216	superio_outb(0, WDT_TIMEOUT);
	217
	218	superio_exit();
	219	return 0;
	220	}
	221
	222	static int it8712f_wdt_notify(struct notifier_block *this,
	223	unsigned long code, void *unused)
	224	{
	225	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	226	if (!nowayout)
	227	it8712f_wdt_disable();
	228
	229	return NOTIFY_DONE;
	230	}
	231
	232	static struct notifier_block it8712f_wdt_notifier = {
	233	.notifier_call = it8712f_wdt_notify,
	234	};
	235
	236	static ssize_t it8712f_wdt_write(struct file file, const char __user data,
	237	size_t len, loff_t *ppos)
	238	{
	239	/* check for a magic close character */
	240	if (len) {
	241	size_t i;
	242
	243	it8712f_wdt_ping();
	244
	245	expect_close = 0;
	246	for (i = 0; i < len; ++i) {
	247	char c;
	248	if (get_user(c, data + i))
	249	return -EFAULT;
	250	if (c == 'V')
	251	expect_close = 42;
	252	}
	253	}
	254
	255	return len;
	256	}
	257
	258	static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
	259	unsigned long arg)
	260	{
	261	void __user argp = (void __user )arg;
	262	int __user *p = argp;
	263	static const struct watchdog_info ident = {
	264	.identity = "IT8712F Watchdog",
	265	.firmware_version = 1,
	266	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	267	WDIOF_MAGICCLOSE,
	268	};
	269	int value;
	270	int ret;
	271
	272	switch (cmd) {
	273	case WDIOC_GETSUPPORT:
	274	if (copy_to_user(argp, &ident, sizeof(ident)))
	275	return -EFAULT;
	276	return 0;
	277	case WDIOC_GETSTATUS:
	278	ret = superio_enter();
	279	if (ret)
	280	return ret;
	281	superio_select(LDN_GPIO);
	282
	283	value = it8712f_wdt_get_status();
	284
	285	superio_exit();
	286
	287	return put_user(value, p);
	288	case WDIOC_GETBOOTSTATUS:
	289	return put_user(0, p);
	290	case WDIOC_KEEPALIVE:
	291	it8712f_wdt_ping();
	292	return 0;
	293	case WDIOC_SETTIMEOUT:
	294	if (get_user(value, p))
	295	return -EFAULT;
	296	if (value < 1)
	297	return -EINVAL;
	298	if (value > (max_units * 60))
	299	return -EINVAL;
	300	margin = value;
	301	ret = superio_enter();
	302	if (ret)
	303	return ret;
	304	superio_select(LDN_GPIO);
	305
	306	it8712f_wdt_update_margin();
	307
	308	superio_exit();
	309	it8712f_wdt_ping();
	310	/* Fall through */
	311	case WDIOC_GETTIMEOUT:
	312	if (put_user(margin, p))
	313	return -EFAULT;
	314	return 0;
	315	default:
	316	return -ENOTTY;
	317	}
	318	}
	319
	320	static int it8712f_wdt_open(struct inode inode, struct file file)
	321	{
	322	int ret;
	323	/* only allow one at a time */
	324	if (test_and_set_bit(0, &wdt_open))
	325	return -EBUSY;
	326
	327	ret = it8712f_wdt_enable();
	328	if (ret)
	329	return ret;
	330	return nonseekable_open(inode, file);
	331	}
	332
	333	static int it8712f_wdt_release(struct inode inode, struct file file)
	334	{
	335	if (expect_close != 42) {
	336	pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	337	} else if (!nowayout) {
	338	if (it8712f_wdt_disable())
	339	pr_warn("Watchdog disable failed\n");
	340	}
	341	expect_close = 0;
	342	clear_bit(0, &wdt_open);
	343
	344	return 0;
	345	}
	346
	347	static const struct file_operations it8712f_wdt_fops = {
	348	.owner = THIS_MODULE,
	349	.llseek = no_llseek,
	350	.write = it8712f_wdt_write,
	351	.unlocked_ioctl = it8712f_wdt_ioctl,
	352	.open = it8712f_wdt_open,
	353	.release = it8712f_wdt_release,
	354	};
	355
	356	static struct miscdevice it8712f_wdt_miscdev = {
	357	.minor = WATCHDOG_MINOR,
	358	.name = "watchdog",
	359	.fops = &it8712f_wdt_fops,
	360	};
	361
	362	static int __init it8712f_wdt_find(unsigned short *address)
	363	{
	364	int err = -ENODEV;
	365	int chip_type;
	366	int ret = superio_enter();
	367	if (ret)
	368	return ret;
	369
	370	chip_type = superio_inw(DEVID);
	371	if (chip_type != IT8712F_DEVID)
	372	goto exit;
	373
	374	superio_select(LDN_GAME);
	375	superio_outb(1, ACT_REG);
	376	if (!(superio_inb(ACT_REG) & 0x01)) {
	377	pr_err("Device not activated, skipping\n");
	378	goto exit;
	379	}
	380
	381	*address = superio_inw(BASE_REG);
	382	if (*address == 0) {
	383	pr_err("Base address not set, skipping\n");
	384	goto exit;
	385	}
	386
	387	err = 0;
	388	revision = superio_inb(DEVREV) & 0x0f;
	389
	390	/* Later revisions have 16-bit values per datasheet 0.9.1 */
	391	if (revision >= 0x08)
	392	max_units = 65535;
	393
	394	if (margin > (max_units * 60))
	395	margin = (max_units * 60);
	396
	397	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
	398	chip_type, revision, *address);
	399
	400	exit:
	401	superio_exit();
	402	return err;
	403	}
	404
	405	static int __init it8712f_wdt_init(void)
	406	{
	407	int err = 0;
	408
	409	if (it8712f_wdt_find(&address))
	410	return -ENODEV;
	411
	412	if (!request_region(address, 1, "IT8712F Watchdog")) {
	413	pr_warn("watchdog I/O region busy\n");
	414	return -EBUSY;
	415	}
	416
	417	err = it8712f_wdt_disable();
	418	if (err) {
	419	pr_err("unable to disable watchdog timer\n");
	420	goto out;
	421	}
	422
	423	err = register_reboot_notifier(&it8712f_wdt_notifier);
	424	if (err) {
	425	pr_err("unable to register reboot notifier\n");
	426	goto out;
	427	}
	428
	429	err = misc_register(&it8712f_wdt_miscdev);
	430	if (err) {
	431	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	432	WATCHDOG_MINOR, err);
	433	goto reboot_out;
	434	}
	435
	436	return 0;
	437
	438
	439	reboot_out:
	440	unregister_reboot_notifier(&it8712f_wdt_notifier);
	441	out:
	442	release_region(address, 1);
	443	return err;
	444	}
	445
	446	static void __exit it8712f_wdt_exit(void)
	447	{
	448	misc_deregister(&it8712f_wdt_miscdev);
	449	unregister_reboot_notifier(&it8712f_wdt_notifier);
	450	release_region(address, 1);
	451	}
	452
	453	module_init(it8712f_wdt_init);
	454	module_exit(it8712f_wdt_exit);