Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / char / watchdog / pcwd_usb.c

/*
 *      Berkshire USB-PC Watchdog Card Driver
 *
 *      (c) Copyright 2004 Wim Van Sebroeck <wim@iguana.be>.
 *
 *      Based on source code of the following authors:
 *        Ken Hollis <kenji@bitgate.com>,
 *        Alan Cox <alan@redhat.com>,
 *        Matt Domsch <Matt_Domsch@dell.com>,
 *        Rob Radez <rob@osinvestor.com>,
 *        Greg Kroah-Hartman <greg@kroah.com>
 *
 *      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.
 *
 *      Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
 *      provide warranty for any of this software. This material is
 *      provided "AS-IS" and at no charge.
 *
 *      Thanks also to Simon Machell at Berkshire Products Inc. for
 *      providing the test hardware. More info is available at
 *      http://www.berkprod.com/ or http://www.pcwatchdog.com/
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <asm/uaccess.h>
#include <linux/usb.h>


#ifdef CONFIG_USB_DEBUG
        static int debug = 1;
#else
        static int debug;
#endif

/* Use our own dbg macro */
#undef dbg
#define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG PFX format "\n" , ## arg); } while (0)


/* Module and Version Information */
#define DRIVER_VERSION "1.01"
#define DRIVER_DATE "15 Mar 2005"
#define DRIVER_AUTHOR "Wim Van Sebroeck <wim@iguana.be>"
#define DRIVER_DESC "Berkshire USB-PC Watchdog driver"
#define DRIVER_LICENSE "GPL"
#define DRIVER_NAME "pcwd_usb"
#define PFX DRIVER_NAME ": "

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE(DRIVER_LICENSE);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS_MISCDEV(TEMP_MINOR);

/* Module Parameters */
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug enabled or not");

#define WATCHDOG_HEARTBEAT 2    /* 2 sec default heartbeat */
static int heartbeat = WATCHDOG_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (0<heartbeat<65536, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

#ifdef CONFIG_WATCHDOG_NOWAYOUT
static int nowayout = 1;
#else
static int nowayout = 0;
#endif

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

/* The vendor and product id's for the USB-PC Watchdog card */
#define USB_PCWD_VENDOR_ID      0x0c98
#define USB_PCWD_PRODUCT_ID     0x1140

/* table of devices that work with this driver */
static struct usb_device_id usb_pcwd_table [] = {
        { USB_DEVICE(USB_PCWD_VENDOR_ID, USB_PCWD_PRODUCT_ID) },
        { }                                     /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, usb_pcwd_table);

/* according to documentation max. time to process a command for the USB
 * watchdog card is 100 or 200 ms, so we give it 250 ms to do it's job */
#define USB_COMMAND_TIMEOUT     250

/* Watchdog's internal commands */
#define CMD_READ_TEMP                   0x02    /* Read Temperature; Re-trigger Watchdog */
#define CMD_TRIGGER                     CMD_READ_TEMP
#define CMD_GET_STATUS                  0x04    /* Get Status Information */
#define CMD_GET_FIRMWARE_VERSION        0x08    /* Get Firmware Version */
#define CMD_GET_DIP_SWITCH_SETTINGS     0x0c    /* Get Dip Switch Settings */
#define CMD_READ_WATCHDOG_TIMEOUT       0x18    /* Read Current Watchdog Time */
#define CMD_WRITE_WATCHDOG_TIMEOUT      0x19    /* Write Current Watchdog Time */
#define CMD_ENABLE_WATCHDOG             0x30    /* Enable / Disable Watchdog */
#define CMD_DISABLE_WATCHDOG            CMD_ENABLE_WATCHDOG

/* Some defines that I like to be somewhere else like include/linux/usb_hid.h */
#define HID_REQ_SET_REPORT              0x09
#define HID_DT_REPORT                   (USB_TYPE_CLASS | 0x02)

/* We can only use 1 card due to the /dev/watchdog restriction */
static int cards_found;

/* some internal variables */
static unsigned long is_active;
static char expect_release;

/* Structure to hold all of our device specific stuff */
struct usb_pcwd_private {
        struct usb_device *     udev;                   /* save off the usb device pointer */
        struct usb_interface *  interface;              /* the interface for this device */

        unsigned int            interface_number;       /* the interface number used for cmd's */

        unsigned char *         intr_buffer;            /* the buffer to intr data */
        dma_addr_t              intr_dma;               /* the dma address for the intr buffer */
        size_t                  intr_size;              /* the size of the intr buffer */
        struct urb *            intr_urb;               /* the urb used for the intr pipe */

        unsigned char           cmd_command;            /* The command that is reported back */
        unsigned char           cmd_data_msb;           /* The data MSB that is reported back */
        unsigned char           cmd_data_lsb;           /* The data LSB that is reported back */
        atomic_t                cmd_received;           /* true if we received a report after a command */

        int                     exists;                 /* Wether or not the device exists */
        struct semaphore        sem;                    /* locks this structure */
};
static struct usb_pcwd_private *usb_pcwd_device;

/* prevent races between open() and disconnect() */
static DECLARE_MUTEX (disconnect_sem);

/* local function prototypes */
static int usb_pcwd_probe       (struct usb_interface *interface, const struct usb_device_id *id);
static void usb_pcwd_disconnect (struct usb_interface *interface);

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver usb_pcwd_driver = {
        .owner =        THIS_MODULE,
        .name =         DRIVER_NAME,
        .probe =        usb_pcwd_probe,
        .disconnect =   usb_pcwd_disconnect,
        .id_table =     usb_pcwd_table,
};


static void usb_pcwd_intr_done(struct urb *urb, struct pt_regs *regs)
{
        struct usb_pcwd_private *usb_pcwd = (struct usb_pcwd_private *)urb->context;
        unsigned char *data = usb_pcwd->intr_buffer;
        int retval;

        switch (urb->status) {
        case 0:                 /* success */
                break;
        case -ECONNRESET:       /* unlink */
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status);
                return;
        /* -EPIPE:  should clear the halt */
        default:                /* error */
                dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status);
                goto resubmit;
        }

        dbg("received following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
                data[0], data[1], data[2]);

        usb_pcwd->cmd_command  = data[0];
        usb_pcwd->cmd_data_msb = data[1];
        usb_pcwd->cmd_data_lsb = data[2];

        /* notify anyone waiting that the cmd has finished */
        atomic_set (&usb_pcwd->cmd_received, 1);

resubmit:
        retval = usb_submit_urb (urb, GFP_ATOMIC);
        if (retval)
                printk(KERN_ERR PFX "can't resubmit intr, usb_submit_urb failed with result %d\n",
                        retval);
}

static int usb_pcwd_send_command(struct usb_pcwd_private *usb_pcwd, unsigned char cmd,
        unsigned char *msb, unsigned char *lsb)
{
        int got_response, count;
        unsigned char buf[6];

        /* We will not send any commands if the USB PCWD device does not exist */
        if ((!usb_pcwd) || (!usb_pcwd->exists))
                return -1;

        /* The USB PC Watchdog uses a 6 byte report format. The board currently uses
         * only 3 of the six bytes of the report. */
        buf[0] = cmd;                   /* Byte 0 = CMD */
        buf[1] = *msb;                  /* Byte 1 = Data MSB */
        buf[2] = *lsb;                  /* Byte 2 = Data LSB */
        buf[3] = buf[4] = buf[5] = 0;   /* All other bytes not used */

        dbg("sending following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
                buf[0], buf[1], buf[2]);

        atomic_set (&usb_pcwd->cmd_received, 0);

        if (usb_control_msg(usb_pcwd->udev, usb_sndctrlpipe(usb_pcwd->udev, 0),
                        HID_REQ_SET_REPORT, HID_DT_REPORT,
                        0x0200, usb_pcwd->interface_number, buf, sizeof(buf),
                        USB_COMMAND_TIMEOUT) != sizeof(buf)) {
                dbg("usb_pcwd_send_command: error in usb_control_msg for cmd 0x%x 0x%x 0x%x\n", cmd, *msb, *lsb);
        }
        /* wait till the usb card processed the command,
         * with a max. timeout of USB_COMMAND_TIMEOUT */
        got_response = 0;
        for (count = 0; (count < USB_COMMAND_TIMEOUT) && (!got_response); count++) {
                mdelay(1);
                if (atomic_read (&usb_pcwd->cmd_received))
                        got_response = 1;
        }

        if ((got_response) && (cmd == usb_pcwd->cmd_command)) {
                /* read back response */
                *msb = usb_pcwd->cmd_data_msb;
                *lsb = usb_pcwd->cmd_data_lsb;
        }

        return got_response;
}

static int usb_pcwd_start(struct usb_pcwd_private *usb_pcwd)
{
        unsigned char msb = 0x00;
        unsigned char lsb = 0x00;
        int retval;

        /* Enable Watchdog */
        retval = usb_pcwd_send_command(usb_pcwd, CMD_ENABLE_WATCHDOG, &msb, &lsb);

        if ((retval == 0) || (lsb == 0)) {
                printk(KERN_ERR PFX "Card did not acknowledge enable attempt\n");
                return -1;
        }

        return 0;
}

static int usb_pcwd_stop(struct usb_pcwd_private *usb_pcwd)
{
        unsigned char msb = 0xA5;
        unsigned char lsb = 0xC3;
        int retval;

        /* Disable Watchdog */
        retval = usb_pcwd_send_command(usb_pcwd, CMD_DISABLE_WATCHDOG, &msb, &lsb);

        if ((retval == 0) || (lsb != 0)) {
                printk(KERN_ERR PFX "Card did not acknowledge disable attempt\n");
                return -1;
        }

        return 0;
}

static int usb_pcwd_keepalive(struct usb_pcwd_private *usb_pcwd)
{
        unsigned char dummy;

        /* Re-trigger Watchdog */
        usb_pcwd_send_command(usb_pcwd, CMD_TRIGGER, &dummy, &dummy);

        return 0;
}

static int usb_pcwd_set_heartbeat(struct usb_pcwd_private *usb_pcwd, int t)
{
        unsigned char msb = t / 256;
        unsigned char lsb = t % 256;

        if ((t < 0x0001) || (t > 0xFFFF))
                return -EINVAL;

        /* Write new heartbeat to watchdog */
        usb_pcwd_send_command(usb_pcwd, CMD_WRITE_WATCHDOG_TIMEOUT, &msb, &lsb);

        heartbeat = t;
        return 0;
}

static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd, int *temperature)
{
        unsigned char msb, lsb;

        usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb);

        /*
         * Convert celsius to fahrenheit, since this was
         * the decided 'standard' for this return value.
         */
        *temperature = (lsb * 9 / 5) + 32;

        return 0;
}

/*
 *      /dev/watchdog handling
 */

static ssize_t usb_pcwd_write(struct file *file, const char __user *data,
                              size_t len, loff_t *ppos)
{
        /* See if we got the magic character 'V' and reload the timer */
        if (len) {
                if (!nowayout) {
                        size_t i;

                        /* note: just in case someone wrote the magic character
                         * five months ago... */
                        expect_release = 0;

                        /* scan to see whether or not we got the magic character */
                        for (i = 0; i != len; i++) {
                                char c;
                                if(get_user(c, data+i))
                                        return -EFAULT;
                                if (c == 'V')
                                        expect_release = 42;
                        }
                }

                /* someone wrote to us, we should reload the timer */
                usb_pcwd_keepalive(usb_pcwd_device);
        }
        return len;
}

static int usb_pcwd_ioctl(struct inode *inode, struct file *file,
                          unsigned int cmd, unsigned long arg)
{
        void __user *argp = (void __user *)arg;
        int __user *p = argp;
        static struct watchdog_info ident = {
                .options =              WDIOF_KEEPALIVEPING |
                                        WDIOF_SETTIMEOUT |
                                        WDIOF_MAGICCLOSE,
                .firmware_version =     1,
                .identity =             DRIVER_NAME,
        };

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

                case WDIOC_GETSTATUS:
                case WDIOC_GETBOOTSTATUS:
                        return put_user(0, p);

                case WDIOC_GETTEMP:
                {
                        int temperature;

                        if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
                                return -EFAULT;

                        return put_user(temperature, p);
                }

                case WDIOC_KEEPALIVE:
                        usb_pcwd_keepalive(usb_pcwd_device);
                        return 0;

                case WDIOC_SETOPTIONS:
                {
                        int new_options, retval = -EINVAL;

                        if (get_user (new_options, p))
                                return -EFAULT;

                        if (new_options & WDIOS_DISABLECARD) {
                                usb_pcwd_stop(usb_pcwd_device);
                                retval = 0;
                        }

                        if (new_options & WDIOS_ENABLECARD) {
                                usb_pcwd_start(usb_pcwd_device);
                                retval = 0;
                        }

                        return retval;
                }

                case WDIOC_SETTIMEOUT:
                {
                        int new_heartbeat;

                        if (get_user(new_heartbeat, p))
                                return -EFAULT;

                        if (usb_pcwd_set_heartbeat(usb_pcwd_device, new_heartbeat))
                            return -EINVAL;

                        usb_pcwd_keepalive(usb_pcwd_device);
                        /* Fall */
                }

                case WDIOC_GETTIMEOUT:
                        return put_user(heartbeat, p);

                default:
                        return -ENOIOCTLCMD;
        }
}

static int usb_pcwd_open(struct inode *inode, struct file *file)
{
        /* /dev/watchdog can only be opened once */
        if (test_and_set_bit(0, &is_active))
                return -EBUSY;

        /* Activate */
        usb_pcwd_start(usb_pcwd_device);
        usb_pcwd_keepalive(usb_pcwd_device);
        return nonseekable_open(inode, file);
}

static int usb_pcwd_release(struct inode *inode, struct file *file)
{
        /*
         *      Shut off the timer.
         */
        if (expect_release == 42) {
                usb_pcwd_stop(usb_pcwd_device);
        } else {
                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
                usb_pcwd_keepalive(usb_pcwd_device);
        }
        expect_release = 0;
        clear_bit(0, &is_active);
        return 0;
}

/*
 *      /dev/temperature handling
 */

static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
                                size_t len, loff_t *ppos)
{
        int temperature;

        if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
                return -EFAULT;

        if (copy_to_user(data, &temperature, 1))
                return -EFAULT;

        return 1;
}

static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
{
        return nonseekable_open(inode, file);
}

static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)
{
        return 0;
}

/*
 *      Notify system
 */

static int usb_pcwd_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
{
        if (code==SYS_DOWN || code==SYS_HALT) {
                /* Turn the WDT off */
                usb_pcwd_stop(usb_pcwd_device);
        }

        return NOTIFY_DONE;
}

/*
 *      Kernel Interfaces
 */

static struct file_operations usb_pcwd_fops = {
        .owner =        THIS_MODULE,
        .llseek =       no_llseek,
        .write =        usb_pcwd_write,
        .ioctl =        usb_pcwd_ioctl,
        .open =         usb_pcwd_open,
        .release =      usb_pcwd_release,
};

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

static struct file_operations usb_pcwd_temperature_fops = {
        .owner =        THIS_MODULE,
        .llseek =       no_llseek,
        .read =         usb_pcwd_temperature_read,
        .open =         usb_pcwd_temperature_open,
        .release =      usb_pcwd_temperature_release,
};

static struct miscdevice usb_pcwd_temperature_miscdev = {
        .minor =        TEMP_MINOR,
        .name =         "temperature",
        .fops =         &usb_pcwd_temperature_fops,
};

static struct notifier_block usb_pcwd_notifier = {
        .notifier_call =        usb_pcwd_notify_sys,
};

/**
 *      usb_pcwd_delete
 */
static inline void usb_pcwd_delete (struct usb_pcwd_private *usb_pcwd)
{
        if (usb_pcwd->intr_urb != NULL)
                usb_free_urb (usb_pcwd->intr_urb);
        if (usb_pcwd->intr_buffer != NULL)
                usb_buffer_free(usb_pcwd->udev, usb_pcwd->intr_size,
                                usb_pcwd->intr_buffer, usb_pcwd->intr_dma);
        kfree (usb_pcwd);
}

/**
 *      usb_pcwd_probe
 *
 *      Called by the usb core when a new device is connected that it thinks
 *      this driver might be interested in.
 */
static int usb_pcwd_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
        struct usb_pcwd_private *usb_pcwd = NULL;
        int pipe, maxp;
        int retval = -ENOMEM;
        int got_fw_rev;
        unsigned char fw_rev_major, fw_rev_minor;
        char fw_ver_str[20];
        unsigned char option_switches, dummy;

        cards_found++;
        if (cards_found > 1) {
                printk(KERN_ERR PFX "This driver only supports 1 device\n");
                return -ENODEV;
        }

        /* get the active interface descriptor */
        iface_desc = interface->cur_altsetting;

        /* check out that we have a HID device */
        if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
                printk(KERN_ERR PFX "The device isn't a Human Interface Device\n");
                return -ENODEV;
        }

        /* check out the endpoint: it has to be Interrupt & IN */
        endpoint = &iface_desc->endpoint[0].desc;

        if (!((endpoint->bEndpointAddress & USB_DIR_IN) &&
             ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
                                == USB_ENDPOINT_XFER_INT))) {
                /* we didn't find a Interrupt endpoint with direction IN */
                printk(KERN_ERR PFX "Couldn't find an INTR & IN endpoint\n");
                return -ENODEV;
        }

        /* get a handle to the interrupt data pipe */
        pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
        maxp = usb_maxpacket(udev, pipe, usb_pipeout(pipe));

        /* allocate memory for our device and initialize it */
        usb_pcwd = kmalloc (sizeof(struct usb_pcwd_private), GFP_KERNEL);
        if (usb_pcwd == NULL) {
                printk(KERN_ERR PFX "Out of memory\n");
                goto error;
        }
        memset (usb_pcwd, 0x00, sizeof (*usb_pcwd));

        usb_pcwd_device = usb_pcwd;

        init_MUTEX (&usb_pcwd->sem);
        usb_pcwd->udev = udev;
        usb_pcwd->interface = interface;
        usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
        usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ? le16_to_cpu(endpoint->wMaxPacketSize) : 8);

        /* set up the memory buffer's */
        if (!(usb_pcwd->intr_buffer = usb_buffer_alloc(udev, usb_pcwd->intr_size, SLAB_ATOMIC, &usb_pcwd->intr_dma))) {
                printk(KERN_ERR PFX "Out of memory\n");
                goto error;
        }

        /* allocate the urb's */
        usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!usb_pcwd->intr_urb) {
                printk(KERN_ERR PFX "Out of memory\n");
                goto error;
        }

        /* initialise the intr urb's */
        usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
                        usb_pcwd->intr_buffer, usb_pcwd->intr_size,
                        usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
        usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
        usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

        /* register our interrupt URB with the USB system */
        if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
                printk(KERN_ERR PFX "Problem registering interrupt URB\n");
                retval = -EIO; /* failure */
                goto error;
        }

        /* The device exists and can be communicated with */
        usb_pcwd->exists = 1;

        /* disable card */
        usb_pcwd_stop(usb_pcwd);

        /* Get the Firmware Version */
        got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION, &fw_rev_major, &fw_rev_minor);
        if (got_fw_rev) {
                sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
        } else {
                sprintf(fw_ver_str, "<card no answer>");
        }

        printk(KERN_INFO PFX "Found card (Firmware: %s) with temp option\n",
                fw_ver_str);

        /* Get switch settings */
        usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy, &option_switches);

        printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
                option_switches,
                ((option_switches & 0x10) ? "ON" : "OFF"),
                ((option_switches & 0x08) ? "ON" : "OFF"));

        /* Check that the heartbeat value is within it's range ; if not reset to the default */
        if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
                usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
                printk(KERN_INFO PFX "heartbeat value must be 0<heartbeat<65536, using %d\n",
                        WATCHDOG_HEARTBEAT);
        }

        retval = register_reboot_notifier(&usb_pcwd_notifier);
        if (retval != 0) {
                printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
                        retval);
                goto error;
        }

        retval = misc_register(&usb_pcwd_temperature_miscdev);
        if (retval != 0) {
                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
                        TEMP_MINOR, retval);
                goto err_out_unregister_reboot;
        }

        retval = misc_register(&usb_pcwd_miscdev);
        if (retval != 0) {
                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
                        WATCHDOG_MINOR, retval);
                goto err_out_misc_deregister;
        }

        /* we can register the device now, as it is ready */
        usb_set_intfdata (interface, usb_pcwd);

        printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
                heartbeat, nowayout);

        return 0;

err_out_misc_deregister:
        misc_deregister(&usb_pcwd_temperature_miscdev);
err_out_unregister_reboot:
        unregister_reboot_notifier(&usb_pcwd_notifier);
error:
        usb_pcwd_delete (usb_pcwd);
        usb_pcwd_device = NULL;
        return retval;
}


/**
 *      usb_pcwd_disconnect
 *
 *      Called by the usb core when the device is removed from the system.
 *
 *      This routine guarantees that the driver will not submit any more urbs
 *      by clearing dev->udev.
 */
static void usb_pcwd_disconnect(struct usb_interface *interface)
{
        struct usb_pcwd_private *usb_pcwd;

        /* prevent races with open() */
        down (&disconnect_sem);

        usb_pcwd = usb_get_intfdata (interface);
        usb_set_intfdata (interface, NULL);

        down (&usb_pcwd->sem);

        /* Stop the timer before we leave */
        if (!nowayout)
                usb_pcwd_stop(usb_pcwd);

        /* We should now stop communicating with the USB PCWD device */
        usb_pcwd->exists = 0;

        /* Deregister */
        misc_deregister(&usb_pcwd_miscdev);
        misc_deregister(&usb_pcwd_temperature_miscdev);
        unregister_reboot_notifier(&usb_pcwd_notifier);

        up (&usb_pcwd->sem);

        /* Delete the USB PCWD device */
        usb_pcwd_delete(usb_pcwd);

        cards_found--;

        up (&disconnect_sem);

        printk(KERN_INFO PFX "USB PC Watchdog disconnected\n");
}



/**
 *      usb_pcwd_init
 */
static int __init usb_pcwd_init(void)
{
        int result;

        /* register this driver with the USB subsystem */
        result = usb_register(&usb_pcwd_driver);
        if (result) {
                printk(KERN_ERR PFX "usb_register failed. Error number %d\n",
                    result);
                return result;
        }

        printk(KERN_INFO PFX DRIVER_DESC " v" DRIVER_VERSION " (" DRIVER_DATE ")\n");
        return 0;
}


/**
 *      usb_pcwd_exit
 */
static void __exit usb_pcwd_exit(void)
{
        /* deregister this driver with the USB subsystem */
        usb_deregister(&usb_pcwd_driver);
}


module_init (usb_pcwd_init);
module_exit (usb_pcwd_exit);