/***************************************************************************
 *   Copyright (C) 2006 by Hans Edgington <hans@edgington.nl>              *
 *   Copyright (C) 2007-2009 Hans de Goede <hdegoede@redhat.com>           *
 *   Copyright (C) 2010 Giel van Schijndel <me@mortis.eu>                  *
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define DRVNAME "f71808e_wdt"

#define SIO_F71808FG_LD_WDT     0x07    /* Watchdog timer logical device */
#define SIO_UNLOCK_KEY          0x87    /* Key to enable Super-I/O */
#define SIO_LOCK_KEY            0xAA    /* Key to disable Super-I/O */

#define SIO_REG_LDSEL           0x07    /* Logical device select */
#define SIO_REG_DEVID           0x20    /* Device ID (2 bytes) */
#define SIO_REG_DEVREV          0x22    /* Device revision */
#define SIO_REG_MANID           0x23    /* Fintek ID (2 bytes) */
#define SIO_REG_ROM_ADDR_SEL    0x27    /* ROM address select */
#define SIO_F81866_REG_PORT_SEL 0x27    /* F81866 Multi-Function Register */
#define SIO_REG_MFUNCT1         0x29    /* Multi function select 1 */
#define SIO_REG_MFUNCT2         0x2a    /* Multi function select 2 */
#define SIO_REG_MFUNCT3         0x2b    /* Multi function select 3 */
#define SIO_F81866_REG_GPIO1    0x2c    /* F81866 GPIO1 Enable Register */
#define SIO_REG_ENABLE          0x30    /* Logical device enable */
#define SIO_REG_ADDR            0x60    /* Logical device address (2 bytes) */

#define SIO_FINTEK_ID           0x1934  /* Manufacturers ID */
#define SIO_F71808_ID           0x0901  /* Chipset ID */
#define SIO_F71858_ID           0x0507  /* Chipset ID */
#define SIO_F71862_ID           0x0601  /* Chipset ID */
#define SIO_F71868_ID           0x1106  /* Chipset ID */
#define SIO_F71869_ID           0x0814  /* Chipset ID */
#define SIO_F71869A_ID          0x1007  /* Chipset ID */
#define SIO_F71882_ID           0x0541  /* Chipset ID */
#define SIO_F71889_ID           0x0723  /* Chipset ID */
#define SIO_F81865_ID           0x0704  /* Chipset ID */
#define SIO_F81866_ID           0x1010  /* Chipset ID */

#define F71808FG_REG_WDO_CONF           0xf0
#define F71808FG_REG_WDT_CONF           0xf5
#define F71808FG_REG_WD_TIME            0xf6

#define F71808FG_FLAG_WDOUT_EN          7

#define F71808FG_FLAG_WDTMOUT_STS       6
#define F71808FG_FLAG_WD_EN             5
#define F71808FG_FLAG_WD_PULSE          4
#define F71808FG_FLAG_WD_UNIT           3

#define F81865_REG_WDO_CONF             0xfa
#define F81865_FLAG_WDOUT_EN            0

/* Default values */
#define WATCHDOG_TIMEOUT        60      /* 1 minute default timeout */
#define WATCHDOG_MAX_TIMEOUT    (60 * 255)
#define WATCHDOG_PULSE_WIDTH    125     /* 125 ms, default pulse width for
                                           watchdog signal */
#define WATCHDOG_F71862FG_PIN   63      /* default watchdog reset output
                                           pin number 63 */

static unsigned short force_id;
module_param(force_id, ushort, 0);
MODULE_PARM_DESC(force_id, "Override the detected device ID");

static const int max_timeout = WATCHDOG_MAX_TIMEOUT;
static int timeout = WATCHDOG_TIMEOUT;  /* default timeout in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
        "Watchdog timeout in seconds. 1<= timeout <="
                        __MODULE_STRING(WATCHDOG_MAX_TIMEOUT) " (default="
                        __MODULE_STRING(WATCHDOG_TIMEOUT) ")");

static unsigned int pulse_width = WATCHDOG_PULSE_WIDTH;
module_param(pulse_width, uint, 0);
MODULE_PARM_DESC(pulse_width,
        "Watchdog signal pulse width. 0(=level), 1, 25, 30, 125, 150, 5000 or 6000 ms"
                        " (default=" __MODULE_STRING(WATCHDOG_PULSE_WIDTH) ")");

static unsigned int f71862fg_pin = WATCHDOG_F71862FG_PIN;
module_param(f71862fg_pin, uint, 0);
MODULE_PARM_DESC(f71862fg_pin,
        "Watchdog f71862fg reset output pin configuration. Choose pin 56 or 63"
                        " (default=" __MODULE_STRING(WATCHDOG_F71862FG_PIN)")");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0444);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

static unsigned int start_withtimeout;
module_param(start_withtimeout, uint, 0);
MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
        " given initial timeout. Zero (default) disables this feature.");

enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
             f81865, f81866};

static const char *f71808e_names[] = {
        "f71808fg",
        "f71858fg",
        "f71862fg",
        "f71868",
        "f71869",
        "f71882fg",
        "f71889fg",
        "f81865",
        "f81866",
};

/* Super-I/O Function prototypes */
static inline int superio_inb(int base, int reg);
static inline int superio_inw(int base, int reg);
static inline void superio_outb(int base, int reg, u8 val);
static inline void superio_set_bit(int base, int reg, int bit);
static inline void superio_clear_bit(int base, int reg, int bit);
static inline int superio_enter(int base);
static inline void superio_select(int base, int ld);
static inline void superio_exit(int base);

struct watchdog_data {
        unsigned short  sioaddr;
        enum chips      type;
        unsigned long   opened;
        struct mutex    lock;
        char            expect_close;
        struct watchdog_info ident;

        unsigned short  timeout;
        u8              timer_val;      /* content for the wd_time register */
        char            minutes_mode;
        u8              pulse_val;      /* pulse width flag */
        char            pulse_mode;     /* enable pulse output mode? */
        char            caused_reboot;  /* last reboot was by the watchdog */
};

static struct watchdog_data watchdog = {
        .lock = __MUTEX_INITIALIZER(watchdog.lock),
};

/* Super I/O functions */
static inline int superio_inb(int base, int reg)
{
        outb(reg, base);
        return inb(base + 1);
}

static int superio_inw(int base, int reg)
{
        int val;
        val  = superio_inb(base, reg) << 8;
        val |= superio_inb(base, reg + 1);
        return val;
}

static inline void superio_outb(int base, int reg, u8 val)
{
        outb(reg, base);
        outb(val, base + 1);
}

static inline void superio_set_bit(int base, int reg, int bit)
{
        unsigned long val = superio_inb(base, reg);
        __set_bit(bit, &val);
        superio_outb(base, reg, val);
}

static inline void superio_clear_bit(int base, int reg, int bit)
{
        unsigned long val = superio_inb(base, reg);
        __clear_bit(bit, &val);
        superio_outb(base, reg, val);
}

static inline int superio_enter(int base)
{
        /* Don't step on other drivers' I/O space by accident */
        if (!request_muxed_region(base, 2, DRVNAME)) {
                pr_err("I/O address 0x%04x already in use\n", (int)base);
                return -EBUSY;
        }

        /* according to the datasheet the key must be sent twice! */
        outb(SIO_UNLOCK_KEY, base);
        outb(SIO_UNLOCK_KEY, base);

        return 0;
}

static inline void superio_select(int base, int ld)
{
        outb(SIO_REG_LDSEL, base);
        outb(ld, base + 1);
}

static inline void superio_exit(int base)
{
        outb(SIO_LOCK_KEY, base);
        release_region(base, 2);
}

static int watchdog_set_timeout(int timeout)
{
        if (timeout <= 0
         || timeout >  max_timeout) {
                pr_err("watchdog timeout out of range\n");
                return -EINVAL;
        }

        mutex_lock(&watchdog.lock);

        watchdog.timeout = timeout;
        if (timeout > 0xff) {
                watchdog.timer_val = DIV_ROUND_UP(timeout, 60);
                watchdog.minutes_mode = true;
        } else {
                watchdog.timer_val = timeout;
                watchdog.minutes_mode = false;
        }

        mutex_unlock(&watchdog.lock);

        return 0;
}

static int watchdog_set_pulse_width(unsigned int pw)
{
        int err = 0;
        unsigned int t1 = 25, t2 = 125, t3 = 5000;

        if (watchdog.type == f71868) {
                t1 = 30;
                t2 = 150;
                t3 = 6000;
        }

        mutex_lock(&watchdog.lock);

        if        (pw <=  1) {
                watchdog.pulse_val = 0;
        } else if (pw <= t1) {
                watchdog.pulse_val = 1;
        } else if (pw <= t2) {
                watchdog.pulse_val = 2;
        } else if (pw <= t3) {
                watchdog.pulse_val = 3;
        } else {
                pr_err("pulse width out of range\n");
                err = -EINVAL;
                goto exit_unlock;
        }

        watchdog.pulse_mode = pw;

exit_unlock:
        mutex_unlock(&watchdog.lock);
        return err;
}

static int watchdog_keepalive(void)
{
        int err = 0;

        mutex_lock(&watchdog.lock);
        err = superio_enter(watchdog.sioaddr);
        if (err)
                goto exit_unlock;
        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

        if (watchdog.minutes_mode)
                /* select minutes for timer units */
                superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                                F71808FG_FLAG_WD_UNIT);
        else
                /* select seconds for timer units */
                superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                                F71808FG_FLAG_WD_UNIT);

        /* Set timer value */
        superio_outb(watchdog.sioaddr, F71808FG_REG_WD_TIME,
                           watchdog.timer_val);

        superio_exit(watchdog.sioaddr);

exit_unlock:
        mutex_unlock(&watchdog.lock);
        return err;
}

static int f71862fg_pin_configure(unsigned short ioaddr)
{
        /* When ioaddr is non-zero the calling function has to take care of
           mutex handling and superio preparation! */

        if (f71862fg_pin == 63) {
                if (ioaddr) {
                        /* SPI must be disabled first to use this pin! */
                        superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);
                        superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);
                }
        } else if (f71862fg_pin == 56) {
                if (ioaddr)
                        superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);
        } else {
                pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
                return -EINVAL;
        }
        return 0;
}

static int watchdog_start(void)
{
        /* Make sure we don't die as soon as the watchdog is enabled below */
        int err = watchdog_keepalive();
        if (err)
                return err;

        mutex_lock(&watchdog.lock);
        err = superio_enter(watchdog.sioaddr);
        if (err)
                goto exit_unlock;
        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

        /* Watchdog pin configuration */
        switch (watchdog.type) {
        case f71808fg:
                /* Set pin 21 to GPIO23/WDTRST#, then to WDTRST# */
                superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT2, 3);
                superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 3);
                break;

        case f71862fg:
                err = f71862fg_pin_configure(watchdog.sioaddr);
                if (err)
                        goto exit_superio;
                break;

        case f71868:
        case f71869:
                /* GPIO14 --> WDTRST# */
                superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 4);
                break;

        case f71882fg:
                /* Set pin 56 to WDTRST# */
                superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
                break;

        case f71889fg:
                /* set pin 40 to WDTRST# */
                superio_outb(watchdog.sioaddr, SIO_REG_MFUNCT3,
                        superio_inb(watchdog.sioaddr, SIO_REG_MFUNCT3) & 0xcf);
                break;

        case f81865:
                /* Set pin 70 to WDTRST# */
                superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 5);
                break;

        case f81866:
                /* Set pin 70 to WDTRST# */
                superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
                                  BIT(3) | BIT(0));
                superio_set_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
                                BIT(2));
                /*
                 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
                 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
                 *     BIT5: 0 -> WDTRST#
                 *           1 -> GPIO15
                 */
                superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1,
                                  BIT(5));
                break;

        default:
                /*
                 * 'default' label to shut up the compiler and catch
                 * programmer errors
                 */
                err = -ENODEV;
                goto exit_superio;
        }

        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
        superio_set_bit(watchdog.sioaddr, SIO_REG_ENABLE, 0);

        if (watchdog.type == f81865 || watchdog.type == f81866)
                superio_set_bit(watchdog.sioaddr, F81865_REG_WDO_CONF,
                                F81865_FLAG_WDOUT_EN);
        else
                superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDO_CONF,
                                F71808FG_FLAG_WDOUT_EN);

        superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                        F71808FG_FLAG_WD_EN);

        if (watchdog.pulse_mode) {
                /* Select "pulse" output mode with given duration */
                u8 wdt_conf = superio_inb(watchdog.sioaddr,
                                F71808FG_REG_WDT_CONF);

                /* Set WD_PSWIDTH bits (1:0) */
                wdt_conf = (wdt_conf & 0xfc) | (watchdog.pulse_val & 0x03);
                /* Set WD_PULSE to "pulse" mode */
                wdt_conf |= BIT(F71808FG_FLAG_WD_PULSE);

                superio_outb(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                                wdt_conf);
        } else {
                /* Select "level" output mode */
                superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                                F71808FG_FLAG_WD_PULSE);
        }

exit_superio:
        superio_exit(watchdog.sioaddr);
exit_unlock:
        mutex_unlock(&watchdog.lock);

        return err;
}

static int watchdog_stop(void)
{
        int err = 0;

        mutex_lock(&watchdog.lock);
        err = superio_enter(watchdog.sioaddr);
        if (err)
                goto exit_unlock;
        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

        superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
                        F71808FG_FLAG_WD_EN);

        superio_exit(watchdog.sioaddr);

exit_unlock:
        mutex_unlock(&watchdog.lock);

        return err;
}

static int watchdog_get_status(void)
{
        int status = 0;

        mutex_lock(&watchdog.lock);
        status = (watchdog.caused_reboot) ? WDIOF_CARDRESET : 0;
        mutex_unlock(&watchdog.lock);

        return status;
}

static bool watchdog_is_running(void)
{
        /*
         * if we fail to determine the watchdog's status assume it to be
         * running to be on the safe side
         */
        bool is_running = true;

        mutex_lock(&watchdog.lock);
        if (superio_enter(watchdog.sioaddr))
                goto exit_unlock;
        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

        is_running = (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
                && (superio_inb(watchdog.sioaddr, F71808FG_REG_WDT_CONF)
                        & F71808FG_FLAG_WD_EN);

        superio_exit(watchdog.sioaddr);

exit_unlock:
        mutex_unlock(&watchdog.lock);
        return is_running;
}

/* /dev/watchdog api */

static int watchdog_open(struct inode *inode, struct file *file)
{
        int err;

        /* If the watchdog is alive we don't need to start it again */
        if (test_and_set_bit(0, &watchdog.opened))
                return -EBUSY;

        err = watchdog_start();
        if (err) {
                clear_bit(0, &watchdog.opened);
                return err;
        }

        if (nowayout)
                __module_get(THIS_MODULE);

        watchdog.expect_close = 0;
        return nonseekable_open(inode, file);
}

static int watchdog_release(struct inode *inode, struct file *file)
{
        clear_bit(0, &watchdog.opened);

        if (!watchdog.expect_close) {
                watchdog_keepalive();
                pr_crit("Unexpected close, not stopping watchdog!\n");
        } else if (!nowayout) {
                watchdog_stop();
        }
        return 0;
}

/*
 *      watchdog_write:
 *      @file: file handle to the watchdog
 *      @buf: buffer to write
 *      @count: count of bytes
 *      @ppos: pointer to the position to write. No seeks allowed
 *
 *      A write to a watchdog device is defined as a keepalive signal. Any
 *      write of data will do, as we we don't define content meaning.
 */

static ssize_t watchdog_write(struct file *file, const char __user *buf,
                            size_t count, loff_t *ppos)
{
        if (count) {
                if (!nowayout) {
                        size_t i;

                        /* In case it was set long ago */
                        bool expect_close = false;

                        for (i = 0; i != count; i++) {
                                char c;
                                if (get_user(c, buf + i))
                                        return -EFAULT;
                                expect_close = (c == 'V');
                        }

                        /* Properly order writes across fork()ed processes */
                        mutex_lock(&watchdog.lock);
                        watchdog.expect_close = expect_close;
                        mutex_unlock(&watchdog.lock);
                }

                /* someone wrote to us, we should restart timer */
                watchdog_keepalive();
        }
        return count;
}

/*
 *      watchdog_ioctl:
 *      @inode: inode of the device
 *      @file: file handle to the device
 *      @cmd: watchdog command
 *      @arg: argument pointer
 *
 *      The watchdog API defines a common set of functions for all watchdogs
 *      according to their available features.
 */
static long watchdog_ioctl(struct file *file, unsigned int cmd,
        unsigned long arg)
{
        int status;
        int new_options;
        int new_timeout;
        union {
                struct watchdog_info __user *ident;
                int __user *i;
        } uarg;

        uarg.i = (int __user *)arg;

        switch (cmd) {
        case WDIOC_GETSUPPORT:
                return copy_to_user(uarg.ident, &watchdog.ident,
                        sizeof(watchdog.ident)) ? -EFAULT : 0;

        case WDIOC_GETSTATUS:
                status = watchdog_get_status();
                if (status < 0)
                        return status;
                return put_user(status, uarg.i);

        case WDIOC_GETBOOTSTATUS:
                return put_user(0, uarg.i);

        case WDIOC_SETOPTIONS:
                if (get_user(new_options, uarg.i))
                        return -EFAULT;

                if (new_options & WDIOS_DISABLECARD)
                        watchdog_stop();

                if (new_options & WDIOS_ENABLECARD)
                        return watchdog_start();


        case WDIOC_KEEPALIVE:
                watchdog_keepalive();
                return 0;

        case WDIOC_SETTIMEOUT:
                if (get_user(new_timeout, uarg.i))
                        return -EFAULT;

                if (watchdog_set_timeout(new_timeout))
                        return -EINVAL;

                watchdog_keepalive();
                /* Fall */

        case WDIOC_GETTIMEOUT:
                return put_user(watchdog.timeout, uarg.i);

        default:
                return -ENOTTY;

        }
}

static int watchdog_notify_sys(struct notifier_block *this, unsigned long code,
        void *unused)
{
        if (code == SYS_DOWN || code == SYS_HALT)
                watchdog_stop();
        return NOTIFY_DONE;
}

static const struct file_operations watchdog_fops = {
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .open           = watchdog_open,
        .release        = watchdog_release,
        .write          = watchdog_write,
        .unlocked_ioctl = watchdog_ioctl,
};

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

static struct notifier_block watchdog_notifier = {
        .notifier_call = watchdog_notify_sys,
};

static int __init watchdog_init(int sioaddr)
{
        int wdt_conf, err = 0;

        /* No need to lock watchdog.lock here because no entry points
         * into the module have been registered yet.
         */
        watchdog.sioaddr = sioaddr;
        watchdog.ident.options = WDIOC_SETTIMEOUT
                                | WDIOF_MAGICCLOSE
                                | WDIOF_KEEPALIVEPING;

        snprintf(watchdog.ident.identity,
                sizeof(watchdog.ident.identity), "%s watchdog",
                f71808e_names[watchdog.type]);

        err = superio_enter(sioaddr);
        if (err)
                return err;
        superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

        wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
        watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);

        superio_exit(sioaddr);

        err = watchdog_set_timeout(timeout);
        if (err)
                return err;
        err = watchdog_set_pulse_width(pulse_width);
        if (err)
                return err;

        err = register_reboot_notifier(&watchdog_notifier);
        if (err)
                return err;

        err = misc_register(&watchdog_miscdev);
        if (err) {
                pr_err("cannot register miscdev on minor=%d\n",
                       watchdog_miscdev.minor);
                goto exit_reboot;
        }

        if (start_withtimeout) {
                if (start_withtimeout <= 0
                 || start_withtimeout >  max_timeout) {
                        pr_err("starting timeout out of range\n");
                        err = -EINVAL;
                        goto exit_miscdev;
                }

                err = watchdog_start();
                if (err) {
                        pr_err("cannot start watchdog timer\n");
                        goto exit_miscdev;
                }

                mutex_lock(&watchdog.lock);
                err = superio_enter(sioaddr);
                if (err)
                        goto exit_unlock;
                superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);

                if (start_withtimeout > 0xff) {
                        /* select minutes for timer units */
                        superio_set_bit(sioaddr, F71808FG_REG_WDT_CONF,
                                F71808FG_FLAG_WD_UNIT);
                        superio_outb(sioaddr, F71808FG_REG_WD_TIME,
                                DIV_ROUND_UP(start_withtimeout, 60));
                } else {
                        /* select seconds for timer units */
                        superio_clear_bit(sioaddr, F71808FG_REG_WDT_CONF,
                                F71808FG_FLAG_WD_UNIT);
                        superio_outb(sioaddr, F71808FG_REG_WD_TIME,
                                start_withtimeout);
                }

                superio_exit(sioaddr);
                mutex_unlock(&watchdog.lock);

                if (nowayout)
                        __module_get(THIS_MODULE);

                pr_info("watchdog started with initial timeout of %u sec\n",
                        start_withtimeout);
        }

        return 0;

exit_unlock:
        mutex_unlock(&watchdog.lock);
exit_miscdev:
        misc_deregister(&watchdog_miscdev);
exit_reboot:
        unregister_reboot_notifier(&watchdog_notifier);

        return err;
}

static int __init f71808e_find(int sioaddr)
{
        u16 devid;
        int err = superio_enter(sioaddr);
        if (err)
                return err;

        devid = superio_inw(sioaddr, SIO_REG_MANID);
        if (devid != SIO_FINTEK_ID) {
                pr_debug("Not a Fintek device\n");
                err = -ENODEV;
                goto exit;
        }

        devid = force_id ? force_id : superio_inw(sioaddr, SIO_REG_DEVID);
        switch (devid) {
        case SIO_F71808_ID:
                watchdog.type = f71808fg;
                break;
        case SIO_F71862_ID:
                watchdog.type = f71862fg;
                err = f71862fg_pin_configure(0); /* validate module parameter */
                break;
        case SIO_F71868_ID:
                watchdog.type = f71868;
                break;
        case SIO_F71869_ID:
        case SIO_F71869A_ID:
                watchdog.type = f71869;
                break;
        case SIO_F71882_ID:
                watchdog.type = f71882fg;
                break;
        case SIO_F71889_ID:
                watchdog.type = f71889fg;
                break;
        case SIO_F71858_ID:
                /* Confirmed (by datasheet) not to have a watchdog. */
                err = -ENODEV;
                goto exit;
        case SIO_F81865_ID:
                watchdog.type = f81865;
                break;
        case SIO_F81866_ID:
                watchdog.type = f81866;
                break;
        default:
                pr_info("Unrecognized Fintek device: %04x\n",
                        (unsigned int)devid);
                err = -ENODEV;
                goto exit;
        }

        pr_info("Found %s watchdog chip, revision %d\n",
                f71808e_names[watchdog.type],
                (int)superio_inb(sioaddr, SIO_REG_DEVREV));
exit:
        superio_exit(sioaddr);
        return err;
}

static int __init f71808e_init(void)
{
        static const unsigned short addrs[] = { 0x2e, 0x4e };
        int err = -ENODEV;
        int i;

        for (i = 0; i < ARRAY_SIZE(addrs); i++) {
                err = f71808e_find(addrs[i]);
                if (err == 0)
                        break;
        }
        if (i == ARRAY_SIZE(addrs))
                return err;

        return watchdog_init(addrs[i]);
}

static void __exit f71808e_exit(void)
{
        if (watchdog_is_running()) {
                pr_warn("Watchdog timer still running, stopping it\n");
                watchdog_stop();
        }
        misc_deregister(&watchdog_miscdev);
        unregister_reboot_notifier(&watchdog_notifier);
}

MODULE_DESCRIPTION("F71808E Watchdog Driver");
MODULE_AUTHOR("Giel van Schijndel <me@mortis.eu>");
MODULE_LICENSE("GPL");

module_init(f71808e_init);
module_exit(f71808e_exit);