mdc800.c

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/*
 * copyright (C) 1999/2000 by Henning Zabel <[email protected]>
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 *  USB-Kernel Driver for the Mustek MDC800 Digital Camera
 *  (c) 1999/2000 Henning Zabel <[email protected]>
 *
 *
 * The driver brings the USB functions of the MDC800 to Linux.
 * To use the Camera you must support the USB Protocol of the camera
 * to the Kernel Node.
 * The Driver uses a misc device Node. Create it with :
 * mknod /dev/mustek c 180 32
 *
 * The driver supports only one camera.
 * 
 * Fix: mdc800 used sleep_on and slept with io_lock held.
 * Converted sleep_on to waitqueues with schedule_timeout and made io_lock
 * a semaphore from a spinlock.
 * by Oliver Neukum <[email protected]>
 * (02/12/2001)
 * 
 * Identify version on module load.
 * (08/04/2001) gb
 *
 * version 0.7.5
 * Fixed potential SMP races with Spinlocks.
 * Thanks to Oliver Neukum <[email protected]> who 
 * noticed the race conditions.
 * (30/10/2000)
 *
 * Fixed: Setting urb->dev before submitting urb.
 * by Greg KH <[email protected]>
 * (13/10/2000)
 *
 * version 0.7.3
 * bugfix : The mdc800->state field gets set to READY after the
 * the diconnect function sets it to NOT_CONNECTED. This makes the
 * driver running like the camera is connected and causes some
 * hang ups.
 *
 * version 0.7.1
 * MOD_INC and MOD_DEC are changed in usb_probe to prevent load/unload
 * problems when compiled as Module.
 * (04/04/2000)
 *
 * The mdc800 driver gets assigned the USB Minor 32-47. The Registration
 * was updated to use these values.
 * (26/03/2000)
 *
 * The Init und Exit Module Function are updated.
 * (01/03/2000)
 *
 * version 0.7.0
 * Rewrite of the driver : The driver now uses URB's. The old stuff
 * has been removed.
 *
 * version 0.6.0
 * Rewrite of this driver: The Emulation of the rs232 protocoll
 * has been removed from the driver. A special executeCommand function
 * for this driver is included to gphoto.
 * The driver supports two kind of communication to bulk endpoints.
 * Either with the dev->bus->ops->bulk... or with callback function.
 * (09/11/1999)
 *
 * version 0.5.0:
 * first Version that gets a version number. Most of the needed
 * functions work.
 * (20/10/1999)
 */

#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/mutex.h>

#include <linux/usb.h>
#include <linux/fs.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.7.5 (30/10/2000)"
#define DRIVER_AUTHOR "Henning Zabel <[email protected]>"
#define DRIVER_DESC "USB Driver for Mustek MDC800 Digital Camera"

/* Vendor and Product Information */
#define MDC800_VENDOR_ID    0x055f
#define MDC800_PRODUCT_ID   0xa800

/* Timeouts (msec) */
#define TO_DOWNLOAD_GET_READY       1500
#define TO_DOWNLOAD_GET_BUSY        1500
#define TO_WRITE_GET_READY      1000
#define TO_DEFAULT_COMMAND      5000
#define TO_READ_FROM_IRQ        TO_DEFAULT_COMMAND
#define TO_GET_READY            TO_DEFAULT_COMMAND

/* Minor Number of the device (create with mknod /dev/mustek c 180 32) */
#define MDC800_DEVICE_MINOR_BASE 32


/**************************************************************************
    Data and structs
***************************************************************************/


typedef enum {
    NOT_CONNECTED, READY, WORKING, DOWNLOAD
} mdc800_state;


/* Data for the driver */
struct mdc800_data
{
    struct usb_device * dev;            // Device Data
    mdc800_state        state;

    unsigned int        endpoint [4];

    struct urb *        irq_urb;
    wait_queue_head_t   irq_wait;
    int         irq_woken;
    char*           irq_urb_buffer;

    int         camera_busy;          // is camera busy ?
    int             camera_request_ready; // Status to synchronize with irq
    char            camera_response [8];  // last Bytes send after busy

    struct urb *        write_urb;
    char*           write_urb_buffer;
    wait_queue_head_t   write_wait;
    int         written;


    struct urb *        download_urb;
    char*           download_urb_buffer;
    wait_queue_head_t   download_wait;
    int         downloaded;
    int         download_left;      // Bytes left to download ?


    /* Device Data */
    char            out [64];   // Answer Buffer
    int             out_ptr;    // Index to the first not readen byte
    int         out_count;  // Bytes in the buffer

    int         open;       // Camera device open ?
    struct mutex        io_lock;    // IO -lock

    char            in [8];     // Command Input Buffer
    int             in_count;

    int         pic_index;  // Cache for the Imagesize (-1 for nothing cached )
    int         pic_len;
    int         minor;
};


/* Specification of the Endpoints */
static struct usb_endpoint_descriptor mdc800_ed [4] =
{
    { 
        .bLength =      0,
        .bDescriptorType =  0,
        .bEndpointAddress = 0x01,
        .bmAttributes =     0x02,
        .wMaxPacketSize =   cpu_to_le16(8),
        .bInterval =        0,
        .bRefresh =         0,
        .bSynchAddress =    0,
    },
    {
        .bLength =      0,
        .bDescriptorType =  0,
        .bEndpointAddress =     0x82,
        .bmAttributes =     0x03,
        .wMaxPacketSize =   cpu_to_le16(8),
        .bInterval =        0,
        .bRefresh =         0,
        .bSynchAddress =    0,
    },
    {
        .bLength =      0,
        .bDescriptorType =  0,
        .bEndpointAddress =     0x03,
        .bmAttributes =     0x02,
        .wMaxPacketSize =   cpu_to_le16(64),
        .bInterval =        0,
        .bRefresh =         0,
        .bSynchAddress =    0,
    },
    {
        .bLength =      0,
        .bDescriptorType =  0,
        .bEndpointAddress =     0x84,
        .bmAttributes =     0x02,
        .wMaxPacketSize =   cpu_to_le16(64),
        .bInterval =        0,
        .bRefresh =         0,
        .bSynchAddress =    0,
    },
};

/* The Variable used by the driver */
static struct mdc800_data* mdc800;


/***************************************************************************
    The USB Part of the driver
****************************************************************************/

static int mdc800_endpoint_equals (struct usb_endpoint_descriptor *a,struct usb_endpoint_descriptor *b)
{
    return (
           ( a->bEndpointAddress == b->bEndpointAddress )
        && ( a->bmAttributes     == b->bmAttributes     )
        && ( a->wMaxPacketSize   == b->wMaxPacketSize   )
    );
}


/*
 * Checks whether the camera responds busy
 */
static int mdc800_isBusy (char* ch)
{
    int i=0;
    while (i<8)
    {
        if (ch [i] != (char)0x99)
            return 0;
        i++;
    }
    return 1;
}


/*
 * Checks whether the Camera is ready
 */
static int mdc800_isReady (char *ch)
{
    int i=0;
    while (i<8)
    {
        if (ch [i] != (char)0xbb)
            return 0;
        i++;
    }
    return 1;
}



/*
 * USB IRQ Handler for InputLine
 */
static void mdc800_usb_irq (struct urb *urb)
{
    int data_received=0, wake_up;
    unsigned char* b=urb->transfer_buffer;
    struct mdc800_data* mdc800=urb->context;
    struct device *dev = &mdc800->dev->dev;
    int status = urb->status;

    if (status >= 0) {
        if (mdc800_isBusy (b))
        {
            if (!mdc800->camera_busy)
            {
                mdc800->camera_busy=1;
                dev_dbg(dev, "gets busy\n");
            }
        }
        else
        {
            if (mdc800->camera_busy && mdc800_isReady (b))
            {
                mdc800->camera_busy=0;
                dev_dbg(dev, "gets ready\n");
            }
        }
        if (!(mdc800_isBusy (b) || mdc800_isReady (b)))
        {
            /* Store Data in camera_answer field */
            dev_dbg(dev, "%i %i %i %i %i %i %i %i \n",b[0],b[1],b[2],b[3],b[4],b[5],b[6],b[7]);

            memcpy (mdc800->camera_response,b,8);
            data_received=1;
        }
    }
    wake_up= ( mdc800->camera_request_ready > 0 )
        &&
        (
            ((mdc800->camera_request_ready == 1) && (!mdc800->camera_busy))
        ||
            ((mdc800->camera_request_ready == 2) && data_received)
        ||
            ((mdc800->camera_request_ready == 3) && (mdc800->camera_busy))
        ||
            (status < 0)
        );

    if (wake_up)
    {
        mdc800->camera_request_ready=0;
        mdc800->irq_woken=1;
        wake_up (&mdc800->irq_wait);
    }
}


/*
 * Waits a while until the irq responds that camera is ready
 *
 *  mode : 0: Wait for camera gets ready
 *         1: Wait for receiving data
 *         2: Wait for camera gets busy
 *
 * msec: Time to wait
 */
static int mdc800_usb_waitForIRQ (int mode, int msec)
{
    mdc800->camera_request_ready=1+mode;

    wait_event_timeout(mdc800->irq_wait, mdc800->irq_woken, msec*HZ/1000);
    mdc800->irq_woken = 0;

    if (mdc800->camera_request_ready>0)
    {
        mdc800->camera_request_ready=0;
        dev_err(&mdc800->dev->dev, "timeout waiting for camera.\n");
        return -1;
    }
    
    if (mdc800->state == NOT_CONNECTED)
    {
        printk(KERN_WARNING "mdc800: Camera gets disconnected "
               "during waiting for irq.\n");
        mdc800->camera_request_ready=0;
        return -2;
    }
    
    return 0;
}


/*
 * The write_urb callback function
 */
static void mdc800_usb_write_notify (struct urb *urb)
{
    struct mdc800_data* mdc800=urb->context;
    int status = urb->status;

    if (status != 0)
        dev_err(&mdc800->dev->dev,
            "writing command fails (status=%i)\n", status);
    else
        mdc800->state=READY;
    mdc800->written = 1;
    wake_up (&mdc800->write_wait);
}


/*
 * The download_urb callback function
 */
static void mdc800_usb_download_notify (struct urb *urb)
{
    struct mdc800_data* mdc800=urb->context;
    int status = urb->status;

    if (status == 0) {
        /* Fill output buffer with these data */
        memcpy (mdc800->out,  urb->transfer_buffer, 64);
        mdc800->out_count=64;
        mdc800->out_ptr=0;
        mdc800->download_left-=64;
        if (mdc800->download_left == 0)
        {
            mdc800->state=READY;
        }
    } else {
        dev_err(&mdc800->dev->dev,
            "request bytes fails (status:%i)\n", status);
    }
    mdc800->downloaded = 1;
    wake_up (&mdc800->download_wait);
}


/***************************************************************************
    Probing for the Camera
 ***************************************************************************/

static struct usb_driver mdc800_usb_driver;
static const struct file_operations mdc800_device_ops;
static struct usb_class_driver mdc800_class = {
    .name =     "mdc800%d",
    .fops =     &mdc800_device_ops,
    .minor_base =   MDC800_DEVICE_MINOR_BASE,
};


/*
 * Callback to search the Mustek MDC800 on the USB Bus
 */
static int mdc800_usb_probe (struct usb_interface *intf,
                   const struct usb_device_id *id)
{
    int i,j;
    struct usb_host_interface *intf_desc;
    struct usb_device *dev = interface_to_usbdev (intf);
    int irq_interval=0;
    int retval;

    dev_dbg(&intf->dev, "(%s) called.\n", __func__);


    if (mdc800->dev != NULL)
    {
        dev_warn(&intf->dev, "only one Mustek MDC800 is supported.\n");
        return -ENODEV;
    }

    if (dev->descriptor.bNumConfigurations != 1)
    {
        dev_err(&intf->dev,
            "probe fails -> wrong Number of Configuration\n");
        return -ENODEV;
    }
    intf_desc = intf->cur_altsetting;

    if (
            ( intf_desc->desc.bInterfaceClass != 0xff )
        ||  ( intf_desc->desc.bInterfaceSubClass != 0 )
        || ( intf_desc->desc.bInterfaceProtocol != 0 )
        || ( intf_desc->desc.bNumEndpoints != 4)
    )
    {
        dev_err(&intf->dev, "probe fails -> wrong Interface\n");
        return -ENODEV;
    }

    /* Check the Endpoints */
    for (i=0; i<4; i++)
    {
        mdc800->endpoint[i]=-1;
        for (j=0; j<4; j++)
        {
            if (mdc800_endpoint_equals (&intf_desc->endpoint [j].desc,&mdc800_ed [i]))
            {
                mdc800->endpoint[i]=intf_desc->endpoint [j].desc.bEndpointAddress ;
                if (i==1)
                {
                    irq_interval=intf_desc->endpoint [j].desc.bInterval;
                }
            }
        }
        if (mdc800->endpoint[i] == -1)
        {
            dev_err(&intf->dev, "probe fails -> Wrong Endpoints.\n");
            return -ENODEV;
        }
    }


    dev_info(&intf->dev, "Found Mustek MDC800 on USB.\n");

    mutex_lock(&mdc800->io_lock);

    retval = usb_register_dev(intf, &mdc800_class);
    if (retval) {
        dev_err(&intf->dev, "Not able to get a minor for this device.\n");
        mutex_unlock(&mdc800->io_lock);
        return -ENODEV;
    }

    mdc800->dev=dev;
    mdc800->open=0;

    /* Setup URB Structs */
    usb_fill_int_urb (
        mdc800->irq_urb,
        mdc800->dev,
        usb_rcvintpipe (mdc800->dev,mdc800->endpoint [1]),
        mdc800->irq_urb_buffer,
        8,
        mdc800_usb_irq,
        mdc800,
        irq_interval
    );

    usb_fill_bulk_urb (
        mdc800->write_urb,
        mdc800->dev,
        usb_sndbulkpipe (mdc800->dev, mdc800->endpoint[0]),
        mdc800->write_urb_buffer,
        8,
        mdc800_usb_write_notify,
        mdc800
    );

    usb_fill_bulk_urb (
        mdc800->download_urb,
        mdc800->dev,
        usb_rcvbulkpipe (mdc800->dev, mdc800->endpoint [3]),
        mdc800->download_urb_buffer,
        64,
        mdc800_usb_download_notify,
        mdc800
    );

    mdc800->state=READY;

    mutex_unlock(&mdc800->io_lock);
    
    usb_set_intfdata(intf, mdc800);
    return 0;
}


/*
 * Disconnect USB device (maybe the MDC800)
 */
static void mdc800_usb_disconnect (struct usb_interface *intf)
{
    struct mdc800_data* mdc800 = usb_get_intfdata(intf);

    dev_dbg(&intf->dev, "(%s) called\n", __func__);

    if (mdc800) {
        if (mdc800->state == NOT_CONNECTED)
            return;

        usb_deregister_dev(intf, &mdc800_class);

        /* must be under lock to make sure no URB
           is submitted after usb_kill_urb() */
        mutex_lock(&mdc800->io_lock);
        mdc800->state=NOT_CONNECTED;

        usb_kill_urb(mdc800->irq_urb);
        usb_kill_urb(mdc800->write_urb);
        usb_kill_urb(mdc800->download_urb);
        mutex_unlock(&mdc800->io_lock);

        mdc800->dev = NULL;
        usb_set_intfdata(intf, NULL);
    }
    dev_info(&intf->dev, "Mustek MDC800 disconnected from USB.\n");
}


/***************************************************************************
    The Misc device Part (file_operations)
****************************************************************************/

/*
 * This Function calc the Answersize for a command.
 */
static int mdc800_getAnswerSize (char command)
{
    switch ((unsigned char) command)
    {
        case 0x2a:
        case 0x49:
        case 0x51:
        case 0x0d:
        case 0x20:
        case 0x07:
        case 0x01:
        case 0x25:
        case 0x00:
            return 8;

        case 0x05:
        case 0x3e:
            return mdc800->pic_len;

        case 0x09:
            return 4096;

        default:
            return 0;
    }
}


/*
 * Init the device: (1) alloc mem (2) Increase MOD Count ..
 */
static int mdc800_device_open (struct inode* inode, struct file *file)
{
    int retval=0;
    int errn=0;

    mutex_lock(&mdc800->io_lock);
    
    if (mdc800->state == NOT_CONNECTED)
    {
        errn=-EBUSY;
        goto error_out;
    }
    if (mdc800->open)
    {
        errn=-EBUSY;
        goto error_out;
    }

    mdc800->in_count=0;
    mdc800->out_count=0;
    mdc800->out_ptr=0;
    mdc800->pic_index=0;
    mdc800->pic_len=-1;
    mdc800->download_left=0;

    mdc800->camera_busy=0;
    mdc800->camera_request_ready=0;

    retval=0;
    mdc800->irq_urb->dev = mdc800->dev;
    retval = usb_submit_urb (mdc800->irq_urb, GFP_KERNEL);
    if (retval) {
        dev_err(&mdc800->dev->dev,
            "request USB irq fails (submit_retval=%i).\n", retval);
        errn = -EIO;
        goto error_out;
    }

    mdc800->open=1;
    dev_dbg(&mdc800->dev->dev, "Mustek MDC800 device opened.\n");

error_out:
    mutex_unlock(&mdc800->io_lock);
    return errn;
}


/*
 * Close the Camera and release Memory
 */
static int mdc800_device_release (struct inode* inode, struct file *file)
{
    int retval=0;

    mutex_lock(&mdc800->io_lock);
    if (mdc800->open && (mdc800->state != NOT_CONNECTED))
    {
        usb_kill_urb(mdc800->irq_urb);
        usb_kill_urb(mdc800->write_urb);
        usb_kill_urb(mdc800->download_urb);
        mdc800->open=0;
    }
    else
    {
        retval=-EIO;
    }

    mutex_unlock(&mdc800->io_lock);
    return retval;
}


/*
 * The Device read callback Function
 */
static ssize_t mdc800_device_read (struct file *file, char __user *buf, size_t len, loff_t *pos)
{
    size_t left=len, sts=len; /* single transfer size */
    char __user *ptr = buf;
    int retval;

    mutex_lock(&mdc800->io_lock);
    if (mdc800->state == NOT_CONNECTED)
    {
        mutex_unlock(&mdc800->io_lock);
        return -EBUSY;
    }
    if (mdc800->state == WORKING)
    {
        printk(KERN_WARNING "mdc800: Illegal State \"working\""
               "reached during read ?!\n");
        mutex_unlock(&mdc800->io_lock);
        return -EBUSY;
    }
    if (!mdc800->open)
    {
        mutex_unlock(&mdc800->io_lock);
        return -EBUSY;
    }

    while (left)
    {
        if (signal_pending (current)) 
        {
            mutex_unlock(&mdc800->io_lock);
            return -EINTR;
        }

        sts=left > (mdc800->out_count-mdc800->out_ptr)?mdc800->out_count-mdc800->out_ptr:left;

        if (sts <= 0)
        {
            /* Too less Data in buffer */
            if (mdc800->state == DOWNLOAD)
            {
                mdc800->out_count=0;
                mdc800->out_ptr=0;

                /* Download -> Request new bytes */
                mdc800->download_urb->dev = mdc800->dev;
                retval = usb_submit_urb (mdc800->download_urb, GFP_KERNEL);
                if (retval) {
                    dev_err(&mdc800->dev->dev,
                        "Can't submit download urb "
                        "(retval=%i)\n", retval);
                    mutex_unlock(&mdc800->io_lock);
                    return len-left;
                }
                wait_event_timeout(mdc800->download_wait, mdc800->downloaded,
                                        TO_DOWNLOAD_GET_READY*HZ/1000);
                mdc800->downloaded = 0;
                if (mdc800->download_urb->status != 0)
                {
                    dev_err(&mdc800->dev->dev,
                        "request download-bytes fails "
                        "(status=%i)\n",
                        mdc800->download_urb->status);
                    mutex_unlock(&mdc800->io_lock);
                    return len-left;
                }
            }
            else
            {
                /* No more bytes -> that's an error*/
                mutex_unlock(&mdc800->io_lock);
                return -EIO;
            }
        }
        else
        {
            /* Copy Bytes */
            if (copy_to_user(ptr, &mdc800->out [mdc800->out_ptr],
                        sts)) {
                mutex_unlock(&mdc800->io_lock);
                return -EFAULT;
            }
            ptr+=sts;
            left-=sts;
            mdc800->out_ptr+=sts;
        }
    }

    mutex_unlock(&mdc800->io_lock);
    return len-left;
}


/*
 * The Device write callback Function
 * If a 8Byte Command is received, it will be send to the camera.
 * After this the driver initiates the request for the answer or
 * just waits until the camera becomes ready.
 */
static ssize_t mdc800_device_write (struct file *file, const char __user *buf, size_t len, loff_t *pos)
{
    size_t i=0;
    int retval;

    mutex_lock(&mdc800->io_lock);
    if (mdc800->state != READY)
    {
        mutex_unlock(&mdc800->io_lock);
        return -EBUSY;
    }
    if (!mdc800->open )
    {
        mutex_unlock(&mdc800->io_lock);
        return -EBUSY;
    }

    while (i<len)
    {
        unsigned char c;
        if (signal_pending (current)) 
        {
            mutex_unlock(&mdc800->io_lock);
            return -EINTR;
        }
        
        if(get_user(c, buf+i))
        {
            mutex_unlock(&mdc800->io_lock);
            return -EFAULT;
        }

        /* check for command start */
        if (c == 0x55)
        {
            mdc800->in_count=0;
            mdc800->out_count=0;
            mdc800->out_ptr=0;
            mdc800->download_left=0;
        }

        /* save command byte */
        if (mdc800->in_count < 8)
        {
            mdc800->in[mdc800->in_count] = c;
            mdc800->in_count++;
        }
        else
        {
            mutex_unlock(&mdc800->io_lock);
            return -EIO;
        }

        /* Command Buffer full ? -> send it to camera */
        if (mdc800->in_count == 8)
        {
            int answersize;

            if (mdc800_usb_waitForIRQ (0,TO_GET_READY))
            {
                dev_err(&mdc800->dev->dev,
                    "Camera didn't get ready.\n");
                mutex_unlock(&mdc800->io_lock);
                return -EIO;
            }

            answersize=mdc800_getAnswerSize (mdc800->in[1]);

            mdc800->state=WORKING;
            memcpy (mdc800->write_urb->transfer_buffer, mdc800->in,8);
            mdc800->write_urb->dev = mdc800->dev;
            retval = usb_submit_urb (mdc800->write_urb, GFP_KERNEL);
            if (retval) {
                dev_err(&mdc800->dev->dev,
                    "submitting write urb fails "
                    "(retval=%i)\n", retval);
                mutex_unlock(&mdc800->io_lock);
                return -EIO;
            }
            wait_event_timeout(mdc800->write_wait, mdc800->written, TO_WRITE_GET_READY*HZ/1000);
            mdc800->written = 0;
            if (mdc800->state == WORKING)
            {
                usb_kill_urb(mdc800->write_urb);
                mutex_unlock(&mdc800->io_lock);
                return -EIO;
            }

            switch ((unsigned char) mdc800->in[1])
            {
                case 0x05: /* Download Image */
                case 0x3e: /* Take shot in Fine Mode (WCam Mode) */
                    if (mdc800->pic_len < 0)
                    {
                        dev_err(&mdc800->dev->dev,
                            "call 0x07 before "
                            "0x05,0x3e\n");
                        mdc800->state=READY;
                        mutex_unlock(&mdc800->io_lock);
                        return -EIO;
                    }
                    mdc800->pic_len=-1;

                case 0x09: /* Download Thumbnail */
                    mdc800->download_left=answersize+64;
                    mdc800->state=DOWNLOAD;
                    mdc800_usb_waitForIRQ (0,TO_DOWNLOAD_GET_BUSY);
                    break;


                default:
                    if (answersize)
                    {

                        if (mdc800_usb_waitForIRQ (1,TO_READ_FROM_IRQ))
                        {
                            dev_err(&mdc800->dev->dev, "requesting answer from irq fails\n");
                            mutex_unlock(&mdc800->io_lock);
                            return -EIO;
                        }

                        /* Write dummy data, (this is ugly but part of the USB Protocol */
                        /* if you use endpoint 1 as bulk and not as irq) */
                        memcpy (mdc800->out, mdc800->camera_response,8);

                        /* This is the interpreted answer */
                        memcpy (&mdc800->out[8], mdc800->camera_response,8);

                        mdc800->out_ptr=0;
                        mdc800->out_count=16;

                        /* Cache the Imagesize, if command was getImageSize */
                        if (mdc800->in [1] == (char) 0x07)
                        {
                            mdc800->pic_len=(int) 65536*(unsigned char) mdc800->camera_response[0]+256*(unsigned char) mdc800->camera_response[1]+(unsigned char) mdc800->camera_response[2];

                            dev_dbg(&mdc800->dev->dev, "cached imagesize = %i\n", mdc800->pic_len);
                        }

                    }
                    else
                    {
                        if (mdc800_usb_waitForIRQ (0,TO_DEFAULT_COMMAND))
                        {
                            dev_err(&mdc800->dev->dev, "Command Timeout.\n");
                            mutex_unlock(&mdc800->io_lock);
                            return -EIO;
                        }
                    }
                    mdc800->state=READY;
                    break;
            }
        }
        i++;
    }
    mutex_unlock(&mdc800->io_lock);
    return i;
}


/***************************************************************************
    Init and Cleanup this driver (Structs and types)
****************************************************************************/

/* File Operations of this drivers */
static const struct file_operations mdc800_device_ops =
{
    .owner =    THIS_MODULE,
    .read =     mdc800_device_read,
    .write =    mdc800_device_write,
    .open =     mdc800_device_open,
    .release =  mdc800_device_release,
    .llseek =   noop_llseek,
};



static const struct usb_device_id mdc800_table[] = {
    { USB_DEVICE(MDC800_VENDOR_ID, MDC800_PRODUCT_ID) },
    { }                     /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, mdc800_table);
/*
 * USB Driver Struct for this device
 */
static struct usb_driver mdc800_usb_driver =
{
    .name =     "mdc800",
    .probe =    mdc800_usb_probe,
    .disconnect =   mdc800_usb_disconnect,
    .id_table = mdc800_table
};



/************************************************************************
    Init and Cleanup this driver (Main Functions)
*************************************************************************/

static int __init usb_mdc800_init (void)
{
    int retval = -ENODEV;
    /* Allocate Memory */
    mdc800=kzalloc (sizeof (struct mdc800_data), GFP_KERNEL);
    if (!mdc800)
        goto cleanup_on_fail;

    mdc800->dev = NULL;
    mdc800->state=NOT_CONNECTED;
    mutex_init (&mdc800->io_lock);

    init_waitqueue_head (&mdc800->irq_wait);
    init_waitqueue_head (&mdc800->write_wait);
    init_waitqueue_head (&mdc800->download_wait);

    mdc800->irq_woken = 0;
    mdc800->downloaded = 0;
    mdc800->written = 0;

    mdc800->irq_urb_buffer=kmalloc (8, GFP_KERNEL);
    if (!mdc800->irq_urb_buffer)
        goto cleanup_on_fail;
    mdc800->write_urb_buffer=kmalloc (8, GFP_KERNEL);
    if (!mdc800->write_urb_buffer)
        goto cleanup_on_fail;
    mdc800->download_urb_buffer=kmalloc (64, GFP_KERNEL);
    if (!mdc800->download_urb_buffer)
        goto cleanup_on_fail;

    mdc800->irq_urb=usb_alloc_urb (0, GFP_KERNEL);
    if (!mdc800->irq_urb)
        goto cleanup_on_fail;
    mdc800->download_urb=usb_alloc_urb (0, GFP_KERNEL);
    if (!mdc800->download_urb)
        goto cleanup_on_fail;
    mdc800->write_urb=usb_alloc_urb (0, GFP_KERNEL);
    if (!mdc800->write_urb)
        goto cleanup_on_fail;

    /* Register the driver */
    retval = usb_register(&mdc800_usb_driver);
    if (retval)
        goto cleanup_on_fail;

    printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
           DRIVER_DESC "\n");

    return 0;

    /* Clean driver up, when something fails */

cleanup_on_fail:

    if (mdc800 != NULL)
    {
        printk(KERN_ERR "mdc800: can't alloc memory!\n");

        kfree(mdc800->download_urb_buffer);
        kfree(mdc800->write_urb_buffer);
        kfree(mdc800->irq_urb_buffer);

        usb_free_urb(mdc800->write_urb);
        usb_free_urb(mdc800->download_urb);
        usb_free_urb(mdc800->irq_urb);

        kfree (mdc800);
    }
    mdc800 = NULL;
    return retval;
}


static void __exit usb_mdc800_cleanup (void)
{
    usb_deregister (&mdc800_usb_driver);

    usb_free_urb (mdc800->irq_urb);
    usb_free_urb (mdc800->download_urb);
    usb_free_urb (mdc800->write_urb);

    kfree (mdc800->irq_urb_buffer);
    kfree (mdc800->write_urb_buffer);
    kfree (mdc800->download_urb_buffer);

    kfree (mdc800);
    mdc800 = NULL;
}

module_init (usb_mdc800_init);
module_exit (usb_mdc800_cleanup);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_LICENSE("GPL");