watchdog: f71808e_wdt: new watchdog driver for Fintek F71808E and F71882FG

Add a new watchdog driver for the Fintek F71808E and F71882FG Super I/O
controllers.

Signed-off-by: Giel van Schijndel <me@mortis.eu>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 768 insertions, 0 deletions

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
new file mode 100644
index 000000000000..7e5c266cda48
--- /dev/null
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -0,0 +1,768 @@
+/***************************************************************************
+ *   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.             *
+ ***************************************************************************/
+
+#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 diasble 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_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_F71882_ID           0x0541  /* Chipset ID */
+#define SIO_F71889_ID           0x0723  /* Chipset ID */
+
+#define F71882FG_REG_START              0x01
+
+#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       5
+#define F71808FG_FLAG_WD_EN             5
+#define F71808FG_FLAG_WD_PULSE          4
+#define F71808FG_FLAG_WD_UNIT           3
+
+/* 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 */
+
+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 = 60;        /* 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 ms, 25 ms, 125 ms or 5000 ms"
+                        " (default=" __MODULE_STRING(WATCHDOG_PULSE_WIDTH) ")");
+
+static int 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, f71882fg, f71889fg };
+
+static const char *f71808e_names[] = {
+        "f71808fg",
+        "f71858fg",
+        "f71862fg",
+        "f71882fg",
+        "f71889fg",
+};
+
+/* 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)) {
+                printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
+                                (int)base);
+                return -EBUSY;
+        }
+
+        /* according to the datasheet the key must be send 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) {
+                printk(KERN_ERR DRVNAME ": 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;
+
+        mutex_lock(&watchdog.lock);
+
+        if        (pw <=    1) {
+                watchdog.pulse_val = 0;
+        } else if (pw <=   25) {
+                watchdog.pulse_val = 1;
+        } else if (pw <=  125) {
+                watchdog.pulse_val = 2;
+        } else if (pw <= 5000) {
+                watchdog.pulse_val = 3;
+        } else {
+                printk(KERN_ERR DRVNAME ": 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 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, 0x2a, 3);
+                superio_clear_bit(watchdog.sioaddr, 0x2b, 3);
+                break;
+
+        case f71882fg:
+                /* Set pin 56 to WDTRST# */
+                superio_set_bit(watchdog.sioaddr, 0x29, 1);
+                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);
+        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();
+                printk(KERN_CRIT DRVNAME
+                        ": 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 & 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) {
+                printk(KERN_ERR DRVNAME
+                        ": cannot register miscdev on minor=%d\n",
+                                watchdog_miscdev.minor);
+                goto exit_reboot;
+        }
+
+        if (start_withtimeout) {
+                if (start_withtimeout <= 0
+                 || start_withtimeout >  max_timeout) {
+                        printk(KERN_ERR DRVNAME
+                                ": starting timeout out of range\n");
+                        err = -EINVAL;
+                        goto exit_miscdev;
+                }
+
+                err = watchdog_start();
+                if (err) {
+                        printk(KERN_ERR DRVNAME
+                                ": 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);
+
+                printk(KERN_INFO DRVNAME
+                        ": 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(DRVNAME ": 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_F71882_ID:
+                watchdog.type = f71882fg;
+                break;
+        case SIO_F71862_ID:
+        case SIO_F71889_ID:
+                /* These have a watchdog, though it isn't implemented (yet). */
+                err = -ENOSYS;
+                goto exit;
+        case SIO_F71858_ID:
+                /* Confirmed (by datasheet) not to have a watchdog. */
+                err = -ENODEV;
+                goto exit;
+        default:
+                printk(KERN_INFO DRVNAME ": Unrecognized Fintek device: %04x\n",
+                       (unsigned int)devid);
+                err = -ENODEV;
+                goto exit;
+        }
+
+        printk(KERN_INFO DRVNAME ": 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()) {
+                printk(KERN_WARNING DRVNAME
+                        ": 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);