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* w83697hf/hg WDT driver
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* (c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
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* (c) Copyright 2006 Marcus Junker <junker@anduras.de>
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* Based on w83627hf_wdt.c which is based on advantechwdt.c
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* which is based on wdt.c.
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* Original copyright messages:
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* (c) Copyright 2003 PƔdraig Brady <P@draigBrady.com>
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* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
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* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
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* All Rights Reserved.
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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* Neither Marcus Junker nor ANDURAS AG admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/ioport.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <asm/system.h>
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#define WATCHDOG_NAME "w83697hf/hg WDT"
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#define PFX WATCHDOG_NAME ": "
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#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
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#define WATCHDOG_EARLY_DISABLE 1 /* Disable until userland kicks in */
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static unsigned long wdt_is_open;
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static char expect_close;
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static DEFINE_SPINLOCK(io_lock);
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/* You must set this - there is no sane way to probe for this board. */
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static int wdt_io = 0x2e;
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module_param(wdt_io, int, 0);
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MODULE_PARM_DESC(wdt_io,
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"w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
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static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. 1<= timeout <=255 (default="
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__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int early_disable = WATCHDOG_EARLY_DISABLE;
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module_param(early_disable, int, 0);
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MODULE_PARM_DESC(early_disable,
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"Watchdog gets disabled at boot time (default="
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__MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
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#define W83697HF_EFER (wdt_io + 0) /* Extended Function Enable Register */
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#define W83697HF_EFIR (wdt_io + 0) /* Extended Function Index Register
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#define W83697HF_EFDR (wdt_io + 1) /* Extended Function Data Register */
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static inline void w83697hf_unlock(void)
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outb_p(0x87, W83697HF_EFER); /* Enter extended function mode */
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outb_p(0x87, W83697HF_EFER); /* Again according to manual */
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static inline void w83697hf_lock(void)
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outb_p(0xAA, W83697HF_EFER); /* Leave extended function mode */
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* The three functions w83697hf_get_reg(), w83697hf_set_reg() and
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* w83697hf_write_timeout() must be called with the device unlocked.
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static unsigned char w83697hf_get_reg(unsigned char reg)
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outb_p(reg, W83697HF_EFIR);
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return inb_p(W83697HF_EFDR);
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static void w83697hf_set_reg(unsigned char reg, unsigned char data)
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outb_p(reg, W83697HF_EFIR);
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outb_p(data, W83697HF_EFDR);
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static void w83697hf_write_timeout(int timeout)
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/* Write Timeout counter to CRF4 */
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w83697hf_set_reg(0xF4, timeout);
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static void w83697hf_select_wdt(void)
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w83697hf_set_reg(0x07, 0x08); /* Switch to logic device 8 (GPIO2) */
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static inline void w83697hf_deselect_wdt(void)
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static void w83697hf_init(void)
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w83697hf_select_wdt();
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bbuf = w83697hf_get_reg(0x29);
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/* Set pin 119 to WDTO# mode (= CR29, WDT0) */
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w83697hf_set_reg(0x29, bbuf);
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bbuf = w83697hf_get_reg(0xF3);
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w83697hf_set_reg(0xF3, bbuf); /* Count mode is seconds */
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w83697hf_deselect_wdt();
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static void wdt_ping(void)
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w83697hf_select_wdt();
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w83697hf_write_timeout(timeout);
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w83697hf_deselect_wdt();
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spin_unlock(&io_lock);
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static void wdt_enable(void)
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w83697hf_select_wdt();
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w83697hf_write_timeout(timeout);
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w83697hf_set_reg(0x30, 1); /* Enable timer */
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w83697hf_deselect_wdt();
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spin_unlock(&io_lock);
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static void wdt_disable(void)
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w83697hf_select_wdt();
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w83697hf_set_reg(0x30, 0); /* Disable timer */
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w83697hf_write_timeout(0);
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w83697hf_deselect_wdt();
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spin_unlock(&io_lock);
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static unsigned char wdt_running(void)
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w83697hf_select_wdt();
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t = w83697hf_get_reg(0xF4); /* Read timer */
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w83697hf_deselect_wdt();
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spin_unlock(&io_lock);
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static int wdt_set_heartbeat(int t)
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if (t < 1 || t > 255)
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static ssize_t wdt_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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for (i = 0; i != count; i++) {
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if (get_user(c, buf + i))
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static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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static const struct watchdog_info ident = {
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
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.firmware_version = 1,
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.identity = "W83697HF WDT",
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &ident, sizeof(ident)))
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_SETOPTIONS:
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int options, retval = -EINVAL;
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if (get_user(options, p))
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if (options & WDIOS_DISABLECARD) {
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if (options & WDIOS_ENABLECARD) {
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case WDIOC_KEEPALIVE:
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case WDIOC_SETTIMEOUT:
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if (get_user(new_timeout, p))
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if (wdt_set_heartbeat(new_timeout))
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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static int wdt_open(struct inode *inode, struct file *file)
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if (test_and_set_bit(0, &wdt_is_open))
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return nonseekable_open(inode, file);
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static int wdt_close(struct inode *inode, struct file *file)
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if (expect_close == 42)
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"Unexpected close, not stopping watchdog!\n");
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clear_bit(0, &wdt_is_open);
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* Notifier for system down
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static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
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if (code == SYS_DOWN || code == SYS_HALT)
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wdt_disable(); /* Turn the WDT off */
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static const struct file_operations wdt_fops = {
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.owner = THIS_MODULE,
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.unlocked_ioctl = wdt_ioctl,
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.release = wdt_close,
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static struct miscdevice wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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* The WDT needs to learn about soft shutdowns in order to
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* turn the timebomb registers off.
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static struct notifier_block wdt_notifier = {
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.notifier_call = wdt_notify_sys,
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static int w83697hf_check_wdt(void)
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if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
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"I/O address 0x%x already in use\n", wdt_io);
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printk(KERN_DEBUG PFX
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"Looking for watchdog at address 0x%x\n", wdt_io);
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if (w83697hf_get_reg(0x20) == 0x60) {
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"watchdog found at address 0x%x\n", wdt_io);
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/* Reprotect in case it was a compatible device */
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printk(KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
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release_region(wdt_io, 2);
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static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
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static int __init wdt_init(void)
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int ret, i, found = 0;
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printk(KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
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/* we will autodetect the W83697HF/HG watchdog */
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for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
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wdt_io = w83697hf_ioports[i];
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if (!w83697hf_check_wdt())
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if (!w83697hf_check_wdt())
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printk(KERN_ERR PFX "No W83697HF/HG could be found\n");
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printk(KERN_WARNING PFX "Stopping previously enabled "
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"watchdog until userland kicks in\n");
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if (wdt_set_heartbeat(timeout)) {
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wdt_set_heartbeat(WATCHDOG_TIMEOUT);
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"timeout value must be 1 <= timeout <= 255, using %d\n",
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ret = register_reboot_notifier(&wdt_notifier);
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"cannot register reboot notifier (err=%d)\n", ret);
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ret = misc_register(&wdt_miscdev);
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"cannot register miscdev on minor=%d (err=%d)\n",
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WATCHDOG_MINOR, ret);
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printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
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unregister_reboot_notifier(&wdt_notifier);
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release_region(wdt_io, 2);
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static void __exit wdt_exit(void)
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misc_deregister(&wdt_miscdev);
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unregister_reboot_notifier(&wdt_notifier);
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release_region(wdt_io, 2);
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module_init(wdt_init);
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module_exit(wdt_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
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"Samuel Tardieu <sam@rfc1149.net>");
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MODULE_DESCRIPTION("w83697hf/hg WDT driver");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);