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[davej-history.git] / drivers / usb / scanner.c

/* -*- linux-c -*- */

/* 
 * Driver for USB Scanners (linux-2.4.0test1-ac7)
 *
 * Copyright (C) 1999, 2000 David E. Nelson
 *
 * Portions may be copyright Brad Keryan and Michael Gee.
 *
 * David E. Nelson (dnelson@jump.net)
 * 
 * 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.
 *
 * Originally based upon mouse.c (Brad Keryan) and printer.c (Michael Gee).
 *
 * History
 *
 *  0.1  8/31/1999
 *
 *    Developed/tested using linux-2.3.15 with minor ohci.c changes to
 *    support short packes during bulk xfer mode.  Some testing was
 *    done with ohci-hcd but the performace was low.  Very limited
 *    testing was performed with uhci but I was unable to get it to
 *    work.  Initial relase to the linux-usb development effort.
 *
 *
 *  0.2  10/16/1999
 *
 *    - Device can't be opened unless a scanner is plugged into the USB.
 *    - Finally settled on a reasonable value for the I/O buffer's.
 *    - Cleaned up write_scanner()
 *    - Disabled read/write stats
 *    - A little more code cleanup
 *
 *
 *  0.3  10/18/1999
 *
 *    - Device registration changed to reflect new device
 *      allocation/registration for linux-2.3.22+.
 *    - Adopted David Brownell's <david-b@pacbell.net> technique for 
 *      assigning bulk endpoints.
 *    - Removed unnessesary #include's
 *    - Scanner model now reported via syslog INFO after being detected 
 *      *and* configured.
 *    - Added user specified vendor:product USB ID's which can be passed 
 *      as module parameters.
 *
 *
 *  0.3.1
 *
 *    - Applied patches for linux-2.3.25.
 *    - Error number reporting changed to reflect negative return codes.
 *
 *
 *  0.3.2
 *
 *    - Applied patches for linux-2.3.26 to scanner_init().
 *    - Debug read/write stats now report values as signed decimal.
 *
 *
 *  0.3.3
 *
 *    - Updated the bulk_msg() calls to usb usb_bulk_msg().
 *    - Added a small delay in the write_scanner() method to aid in
 *      avoiding NULL data reads on HP scanners.  We'll see how this works.
 *    - Return values from usb_bulk_msg() now ignore positive values for
 *      use with the ohci driver.
 *    - Added conditional debugging instead of commenting/uncommenting
 *      all over the place.
 *    - kfree()'d the pointer after using usb_string() as documented in
 *      linux-usb-api.txt.
 *    - Added usb_set_configuration().  It got lost in version 0.3 -- ack!
 *    - Added the HP 5200C USB Vendor/Product ID's.
 *
 *
 *  0.3.4  1/23/2000
 *
 *    - Added Greg K-H's <greg@kroah.com> patch for better handling of 
 *      Product/Vendor detection.
 *    - The driver now autoconfigures its endpoints including interrupt
 *      endpoints if one is detected.  The concept was originally based
 *      upon David Brownell's method.
 *    - Added some Seiko/Epson ID's. Thanks to Karl Heinz 
 *      Kremer <khk@khk.net>.
 *    - Added some preliminary ioctl() calls for the PV8630 which is used
 *      by the HP4200. The ioctl()'s still have to be registered. Thanks 
 *      to Adrian Perez Jorge <adrianpj@easynews.com>.
 *    - Moved/migrated stuff to scanner.h
 *    - Removed the usb_set_configuration() since this is handled by
 *      the usb_new_device() routine in usb.c.
 *    - Added the HP 3300C.  Thanks to Bruce Tenison.
 *    - Changed user specified vendor/product id so that root hub doesn't
 *      get falsely attached to. Thanks to Greg K-H.
 *    - Added some Mustek ID's. Thanks to Gernot Hoyler 
 *      <Dr.Hoyler@t-online.de>.
 *    - Modified the usb_string() reporting.  See kfree() comment above.
 *    - Added Umax Astra 2000U. Thanks to Doug Alcorn <doug@lathi.net>.
 *    - Updated the printk()'s to use the info/warn/dbg macros.
 *    - Updated usb_bulk_msg() argument types to fix gcc warnings.
 *
 *
 *  0.4  2/4/2000
 *
 *    - Removed usb_string() from probe_scanner since the core now does a
 *      good job of reporting what was connnected.  
 *    - Finally, simultaneous multiple device attachment!
 *    - Fixed some potential memory freeing issues should memory allocation
 *      fail in probe_scanner();
 *    - Some fixes to disconnect_scanner().
 *    - Added interrupt endpoint support.
 *    - Added Agfa SnapScan Touch. Thanks to Jan Van den Bergh
 *      <jan.vandenbergh@cs.kuleuven.ac.be>.
 *    - Added Umax 1220U ID's. Thanks to Maciek Klimkowski
 *      <mac@nexus.carleton.ca>.
 *    - Fixed bug in write_scanner(). The buffer was not being properly
 *      updated for writes larger than OBUF_SIZE. Thanks to Henrik 
 *      Johansson <henrikjo@post.utfors.se> for identifying it.
 *    - Added Microtek X6 ID's. Thanks to Oliver Neukum
 *      <Oliver.Neukum@lrz.uni-muenchen.de>.
 *
 * 
 *  0.4.1  2/15/2000
 *  
 *    - Fixed 'count' bug in read_scanner(). Thanks to Henrik
 *      Johansson <henrikjo@post.utfors.se> for identifying it.  Amazing
 *      it has worked this long.
 *    - Fixed '>=' bug in both read/write_scanner methods.
 *    - Cleaned up both read/write_scanner() methods so that they are 
 *      a little more readable.
 *    - Added a lot of Microtek ID's.  Thanks to Adrian Perez Jorge.
 *    - Adopted the __initcall().
 *    - Added #include <linux/init.h> to scanner.h for __initcall().
 *    - Added one liner in irq_scanner() to keep gcc from complaining 
 *      about an unused variable (data) if debugging was disabled
 *      in scanner.c.
 *    - Increased the timeout parameter in read_scanner() to 120 Secs.
 *
 *
 *  0.4.2  3/23/2000
 *
 *    - Added Umax 1236U ID.  Thanks to Philipp Baer <ph_baer@npw.net>.
 *    - Added Primax, ReadyScan, Visioneer, Colorado, and Genius ID's.
 *      Thanks to Adrian Perez Jorge <adrianpj@easynews.com>.
 *    - Fixed error number reported for non-existant devices.  Thanks to
 *      Spyridon Papadimitriou <Spyridon_Papadimitriou@gs91.sp.cs.cmu.edu>.
 *    - Added Acer Prisascan 620U ID's.  Thanks to Joao <joey@knoware.nl>.
 *    - Replaced __initcall() with module_init()/module_exit(). Updates
 *      from patch-2.3.48.
 *    - Replaced file_operations structure with new syntax.  Updates
 *      from patch-2.3.49.
 *    - Changed #include "usb.h" to #include <linux/usb.h>
 *    - Added #define SCN_IOCTL to exclude development areas 
 *      since 2.4.x is about to be released. This mainly affects the 
 *      ioctl() stuff.  See scanner.h for more details.
 *    - Changed the return value for signal_pending() from -ERESTARTSYS to
 *      -EINTR.
 *
 *
 * 0.4.3  4/30/2000
 *
 *    - Added Umax Astra 2200 ID.  Thanks to Flynn Marquardt 
 *      <flynn@isr.uni-stuttgart.de>.
 *    - Added iVina 1200U ID. Thanks to Dyson Lin <dyson@avision.com.tw>.
 *    - Added access time update for the device file courtesy of Paul
 *      Mackerras <paulus@linuxcare.com>.  This allows a user space daemon
 *      to turn the lamp off for a Umax 1220U scanner after a prescribed
 *      time.
 *    - Fixed HP S20 ID's.  Thanks to Ruud Linders <rlinders@xs4all.nl>.
 *    - Added Acer ScanPrisa 620U ID. Thanks to Oliver
 *      Schwartz <Oliver.Schwartz@gmx.de> via sane-devel mail list.
 *    - Fixed bug in read_scanner for copy_to_user() function.  The returned
 *      value should be 'partial' not 'this_read'.
 *    - Fixed bug in read_scanner. 'count' should be decremented 
 *      by 'this_read' and not by 'partial'.  This resulted in twice as many
 *      calls to read_scanner() for small amounts of data and possibly
 *      unexpected returns of '0'.  Thanks to Karl Heinz 
 *      Kremer <khk@khk.net> and Alain Knaff <Alain.Knaff@ltnb.lu>
 *      for discovering this.
 *    - Integrated Randy Dunlap's <randy.dunlap@intel.com> patch for a
 *      scanner lookup/ident table. Thanks Randy.
 *    - Documentation updates.
 *    - Added wait queues to read_scanner().
 *
 *
 * 0.4.3.1
 *
 *    - Fixed HP S20 ID's...again..sigh.  Thanks to Ruud
 *      Linders <rlinders@xs4all.nl>.
 *
 *
 *  TODO
 *
 *    - Performance
 *    - Select/poll methods
 *    - More testing
 *    - Proper registry/assignment for LM9830 ioctl's
 *
 *
 *  Thanks to:
 *
 *    - All the folks on the linux-usb list who put up with me. :)  This 
 *      has been a great learning experience for me.
 *    - To Linus Torvalds for this great OS.
 *    - The GNU folks.
 *    - The folks that forwarded Vendor:Product ID's to me.
 *    - Johannes Erdfelt for the loaning of a USB analyzer for tracking an
 *      issue with HP-4100 and uhci.
 *    - Adolfo Montero for his assistance.
 *    - All the folks who chimed in with reports and suggestions.
 *    - All the developers that are working on USB SANE backends or other
 *      applications to use USB scanners.
 *
 *  Performance:
 *
 *    System: Pentium 120, 80 MB RAM, OHCI, Linux 2.3.23, HP 4100C USB Scanner
 *            300 dpi scan of the entire bed
 *      24 Bit Color ~ 70 secs - 3.6 Mbit/sec
 *       8 Bit Gray  ~ 17 secs - 4.2 Mbit/sec
 */

/* 
 * Scanner definitions, macros, module info, 
 * debug/ioctl/data_dump enable, and other constants.
 */ 
#include "scanner.h"

static void
irq_scanner(struct urb *urb)
{

/*
 * For the meantime, this is just a placeholder until I figure out what
 * all I want to do with it -- or somebody else for that matter.
 */

        struct scn_usb_data *scn = urb->context;
        unsigned char *data = &scn->button;
        data += 0;              /* Keep gcc from complaining about unused var */

        if (urb->status) {
                return;
        }

        dbg("irq_scanner(%d): data:%x", scn->scn_minor, *data);
        return;
}


static int
open_scanner(struct inode * inode, struct file * file)
{
        struct scn_usb_data *scn;
        struct usb_device *dev;

        kdev_t scn_minor;

        scn_minor = USB_SCN_MINOR(inode);

        dbg("open_scanner: scn_minor:%d", scn_minor);

        if (!p_scn_table[scn_minor]) {
                err("open_scanner(%d): Unable to access minor data", scn_minor);
                return -ENODEV;
        }

        scn = p_scn_table[scn_minor];

        dev = scn->scn_dev;

        if (!dev) {
                err("open_scanner(%d): Scanner device not present", scn_minor);
                return -ENODEV;
        }

        if (!scn->present) {
                err("open_scanner(%d): Scanner is not present", scn_minor);
                return -ENODEV;
        }

        if (scn->isopen) {
                err("open_scanner(%d): Scanner device is already open", scn_minor);
                return -EBUSY;
        }

        init_waitqueue_head(&scn->rd_wait_q);

        scn->isopen = 1;

        file->private_data = scn; /* Used by the read and write metheds */

        MOD_INC_USE_COUNT;

        return 0;
}

static int
close_scanner(struct inode * inode, struct file * file)
{
        struct scn_usb_data *scn;

        kdev_t scn_minor;

        scn_minor = USB_SCN_MINOR (inode);

        dbg("close_scanner: scn_minor:%d", scn_minor);

        if (!p_scn_table[scn_minor]) {
                err("close_scanner(%d): invalid scn_minor", scn_minor);
                return -ENODEV;
        }

        scn = p_scn_table[scn_minor];

        scn->isopen = 0;

        file->private_data = NULL;

        MOD_DEC_USE_COUNT;

        return 0;
}

static ssize_t
write_scanner(struct file * file, const char * buffer,
              size_t count, loff_t *ppos)
{
        struct scn_usb_data *scn;
        struct usb_device *dev;
        
        ssize_t bytes_written = 0; /* Overall count of bytes written */
        ssize_t ret = 0;

        kdev_t scn_minor;

        int this_write;         /* Number of bytes to write */
        int partial;            /* Number of bytes successfully written */
        int result = 0;
        
        char *obuf;

        scn = file->private_data;

        scn_minor = scn->scn_minor;

        obuf = scn->obuf;

        dev = scn->scn_dev;

        file->f_dentry->d_inode->i_atime = CURRENT_TIME;

        while (count > 0) {

                if (signal_pending(current)) {
                        ret = -EINTR;
                        break;
                }

                this_write = (count >= OBUF_SIZE) ? OBUF_SIZE : count;
                
                if (copy_from_user(scn->obuf, buffer, this_write)) {
                        ret = -EFAULT;
                        break;
                }

                result = usb_bulk_msg(dev,usb_sndbulkpipe(dev, scn->bulk_out_ep), obuf, this_write, &partial, 60*HZ);
                dbg("write stats(%d): result:%d this_write:%d partial:%d", scn_minor, result, this_write, partial);

                if (result == USB_ST_TIMEOUT) { /* NAK -- shouldn't happen */
                        warn("write_scanner: NAK recieved.");
                        ret = -ETIME;
                        break;
                } else if (result < 0) { /* We should not get any I/O errors */
                        warn("write_scanner(%d): funky result: %d. Please notify the maintainer.", scn_minor, result);
                        ret = -EIO;
                        break;
                } 

#ifdef WR_DATA_DUMP
                if (partial) {
                        unsigned char cnt, cnt_max;
                        cnt_max = (partial > 24) ? 24 : partial;
                        printk(KERN_DEBUG "dump(%d): ", scn_minor);
                        for (cnt=0; cnt < cnt_max; cnt++) {
                                printk("%X ", obuf[cnt]);
                        }
                        printk("\n");
                }
#endif
                if (partial != this_write) { /* Unable to write all contents of obuf */
                        ret = -EIO;
                        break;
                }

                if (partial) { /* Data written */
                        buffer += partial;
                        count -= partial;
                        bytes_written += partial;
                } else { /* No data written */
                        ret = 0;
                        break;
                }
        }
        mdelay(5);              /* This seems to help with SANE queries */
        return ret ? ret : bytes_written;
}

static ssize_t
read_scanner(struct file * file, char * buffer,
             size_t count, loff_t *ppos)
{
        struct scn_usb_data *scn;
        struct usb_device *dev;

        ssize_t bytes_read;     /* Overall count of bytes_read */
        ssize_t ret;

        kdev_t scn_minor;

        int partial;            /* Number of bytes successfully read */
        int this_read;          /* Max number of bytes to read */
        int result;
        int rd_expire = RD_EXPIRE;

        char *ibuf;

        scn = file->private_data;

        scn_minor = scn->scn_minor;

        ibuf = scn->ibuf;

        dev = scn->scn_dev;

        bytes_read = 0;
        ret = 0;

        file->f_dentry->d_inode->i_atime = CURRENT_TIME; /* Update the
                                                            atime of
                                                            the device
                                                            node */

        while (count > 0) {
                if (signal_pending(current)) {
                        ret = -EINTR;
                        break;
                }

                this_read = (count >= IBUF_SIZE) ? IBUF_SIZE : count;
                
                result = usb_bulk_msg(dev, usb_rcvbulkpipe(dev, scn->bulk_in_ep), ibuf, this_read, &partial, RD_NAK_TIMEOUT);
                dbg("read stats(%d): result:%d this_read:%d partial:%d count:%d", scn_minor, result, this_read, partial, count);

/* 
 * Scanners are sometimes inheriently slow since they are mechanical
 * in nature.  USB bulk reads tend to timeout while the scanner is
 * positioning, resetting, warming up the lamp, etc if the timeout is
 * set too low.  A very long timeout parameter for bulk reads was used
 * to overcome this limitation, but this sometimes resulted in folks
 * having to wait for the timeout to expire after pressing Ctrl-C from
 * an application. The user was sometimes left with the impression
 * that something had hung or crashed when in fact the USB read was
 * just waiting on data.  So, the below code retains the same long
 * timeout period, but splits it up into smaller parts so that
 * Ctrl-C's are acted upon in a reasonable amount of time. 
 */

                if (result == USB_ST_TIMEOUT && !partial) { /* Timeout
                                                               and no
                                                               data */
                        if (--rd_expire <= 0) {
                                warn("read_scanner(%d): excessive NAK's received", scn_minor);
                                ret = -ETIME;
                                break;
                        } else {
                                interruptible_sleep_on_timeout(&scn->rd_wait_q, RD_NAK_TIMEOUT);
                                continue;
                        }
                } else if ((result < 0) && (result != USB_ST_DATAUNDERRUN)) {
                        warn("read_scanner(%d): funky result:%d. Please notify the maintainer.", scn_minor, (int)result);
                        ret = -EIO;
                        break;
                }

#ifdef RD_DATA_DUMP
                if (partial) {
                        unsigned char cnt, cnt_max;
                        cnt_max = (partial > 24) ? 24 : partial;
                        printk(KERN_DEBUG "dump(%d): ", scn_minor);
                        for (cnt=0; cnt < cnt_max; cnt++) {
                                printk("%X ", ibuf[cnt]);
                        }
                        printk("\n");
                }
#endif

                if (partial) { /* Data returned */
                        if (copy_to_user(buffer, ibuf, partial)) {
                                ret = -EFAULT;
                                break;
                        }
                        count -= this_read; /* Compensate for short reads */
                        bytes_read += partial; /* Keep tally of what actually was read */
                        buffer += partial;
                } else {
                        ret = 0;
                        break;
                }
        }
        
        return ret ? ret : bytes_read;
}

static void *
probe_scanner(struct usb_device *dev, unsigned int ifnum)
{
        struct scn_usb_data *scn;
        struct usb_interface_descriptor *interface;
        struct usb_endpoint_descriptor *endpoint;
        
        int ep_cnt;
        int ix;

        kdev_t scn_minor;

        char valid_device = 0;
        char have_bulk_in, have_bulk_out, have_intr;

        if (vendor != -1 && product != -1) {
                info("probe_scanner: User specified USB scanner -- Vendor:Product - %x:%x", vendor, product);
        }

        dbg("probe_scanner: USB dev address:%p", dev);
        dbg("probe_scanner: ifnum:%u", ifnum);

/*
 * 1. Check Vendor/Product
 * 2. Determine/Assign Bulk Endpoints
 * 3. Determine/Assign Intr Endpoint
 */

/* 
 * There doesn't seem to be an imaging class defined in the USB
 * Spec. (yet).  If there is, HP isn't following it and it doesn't
 * look like anybody else is either.  Therefore, we have to test the
 * Vendor and Product ID's to see what we have.  Also, other scanners
 * may be able to use this driver by specifying both vendor and
 * product ID's as options to the scanner module in conf.modules.
 *
 * NOTE: Just because a product is supported here does not mean that
 * applications exist that support the product.  It's in the hopes
 * that this will allow developers a means to produce applications
 * that will support USB products.
 *
 * Until we detect a device which is pleasing, we silently punt.
 */

        for (ix = 0; ix < sizeof (scanner_device_ids) / sizeof (struct scanner_device); ix++) {
                if ((dev->descriptor.idVendor == scanner_device_ids [ix].idVendor) &&
                    (dev->descriptor.idProduct == scanner_device_ids [ix].idProduct)) {
                        valid_device = 1;
                        break;
                }
        }
        if (dev->descriptor.idVendor == vendor &&   /* User specified */
            dev->descriptor.idProduct == product) { /* User specified */
                valid_device = 1;
        }
        
        if (!valid_device)
                return NULL;    /* We didn't find anything pleasing */

/*
 * After this point we can be a little noisy about what we are trying to
 *  configure.
 */

        if (dev->descriptor.bNumConfigurations != 1) {
                info("probe_scanner: Only one device configuration is supported.");
                return NULL;
        }

        if (dev->config[0].bNumInterfaces != 1) {
                info("probe_scanner: Only one device interface is supported.");
                return NULL;
        }

        interface = dev->config[0].interface[ifnum].altsetting;
        endpoint = interface[ifnum].endpoint;

/* 
 * Start checking for two bulk endpoints OR two bulk endpoints *and* one
 * interrupt endpoint. If we have an interrupt endpoint go ahead and
 * setup the handler. FIXME: This is a future enhancement...
 */

        dbg("probe_scanner: Number of Endpoints:%d", (int) interface->bNumEndpoints);

        if ((interface->bNumEndpoints != 2) && (interface->bNumEndpoints != 3)) {
                info("probe_scanner: Only two or three endpoints supported.");
                return NULL;
        }

        ep_cnt = have_bulk_in = have_bulk_out = have_intr = 0;

        while (ep_cnt < interface->bNumEndpoints) {

                if (!have_bulk_in && IS_EP_BULK_IN(endpoint[ep_cnt])) {
                        ep_cnt++;
                        have_bulk_in = ep_cnt;
                        dbg("probe_scanner: bulk_in_ep:%d", have_bulk_in);
                        continue;
                }
                
                if (!have_bulk_out && IS_EP_BULK_OUT(endpoint[ep_cnt])) {
                        ep_cnt++;
                        have_bulk_out = ep_cnt;
                        dbg("probe_scanner: bulk_out_ep:%d", have_bulk_out);
                        continue;
                }

                if (!have_intr && IS_EP_INTR(endpoint[ep_cnt])) {
                        ep_cnt++;
                        have_intr = ep_cnt;
                        dbg("probe_scanner: intr_ep:%d", have_intr);
                        continue;
                }
                info("probe_scanner: Undetected endpoint. Notify the maintainer.");
                return NULL;    /* Shouldn't ever get here unless we have something weird */
        }


/*
 * Perform a quick check to make sure that everything worked as it
 * should have.
 */

        switch(interface->bNumEndpoints) {
        case 2:
                if (!have_bulk_in || !have_bulk_out) {
                        info("probe_scanner: Two bulk endpoints required.");
                        return NULL;
                }
                break;
        case 3:
                if (!have_bulk_in || !have_bulk_out || !have_intr) {
                        info("probe_scanner: Two bulk endpoints and one interrupt endpoint required.");
                        return NULL;
                }
                break;
        default:
                info("probe_scanner: Endpoint determination failed.  Notify the maintainer.");
                return NULL;
        }


/* 
 * Determine a minor number and initialize the structure associated
 * with it.  The problem with this is that we are counting on the fact
 * that the user will sequentially add device nodes for the scanner
 * devices.  */

        for (scn_minor = 0; scn_minor < SCN_MAX_MNR; scn_minor++) {
                if (!p_scn_table[scn_minor])
                        break;
        }

/* Check to make sure that the last slot isn't already taken */
        if (p_scn_table[scn_minor]) {
                err("probe_scanner: No more minor devices remaining.");
                return NULL;
        }

        dbg("probe_scanner: Allocated minor:%d", scn_minor);

        if (!(scn = kmalloc (sizeof (struct scn_usb_data), GFP_KERNEL))) {
                err("probe_scanner: Out of memory.");
                return NULL;
        }
        memset (scn, 0, sizeof(struct scn_usb_data));
        dbg ("probe_scanner(%d): Address of scn:%p", scn_minor, scn);


/* Ok, if we detected an interrupt EP, setup a handler for it */
        if (have_intr) {
                dbg("probe_scanner(%d): Configuring IRQ handler for intr EP:%d", scn_minor, have_intr);
                FILL_INT_URB(&scn->scn_irq, dev, 
                             usb_rcvintpipe(dev, have_intr),
                             &scn->button, 1, irq_scanner, scn,
                             // endpoint[(int)have_intr].bInterval);
                             250);

                if (usb_submit_urb(&scn->scn_irq)) {
                        err("probe_scanner(%d): Unable to allocate INT URB.", scn_minor);
                        kfree(scn);
                        return NULL;
                }
        }


/* Ok, now initialize all the relevant values */
        if (!(scn->obuf = (char *)kmalloc(OBUF_SIZE, GFP_KERNEL))) {
                err("probe_scanner(%d): Not enough memory for the output buffer.", scn_minor);
                kfree(scn);
                return NULL;
        }
        dbg("probe_scanner(%d): obuf address:%p", scn_minor, scn->obuf);

        if (!(scn->ibuf = (char *)kmalloc(IBUF_SIZE, GFP_KERNEL))) {
                err("probe_scanner(%d): Not enough memory for the input buffer.", scn_minor);
                kfree(scn->obuf);
                kfree(scn);
                return NULL;
        }
        dbg("probe_scanner(%d): ibuf address:%p", scn_minor, scn->ibuf);

        scn->bulk_in_ep = have_bulk_in;
        scn->bulk_out_ep = have_bulk_out;
        scn->intr_ep = have_intr;
        scn->present = 1;
        scn->scn_dev = dev;
        scn->scn_minor = scn_minor;
        scn->isopen = 0;

        return p_scn_table[scn_minor] = scn;
}

static void
disconnect_scanner(struct usb_device *dev, void *ptr)
{
        struct scn_usb_data *scn = (struct scn_usb_data *) ptr;
        
        if(scn->intr_ep) {
                dbg("disconnect_scanner(%d): Unlinking IRQ URB", scn->scn_minor);
                usb_unlink_urb(&scn->scn_irq);
        }
        usb_driver_release_interface(&scanner_driver,
                &scn->scn_dev->actconfig->interface[scn->ifnum]);

        kfree(scn->ibuf);
        kfree(scn->obuf);

        dbg("disconnect_scanner: De-allocating minor:%d", scn->scn_minor);
        p_scn_table[scn->scn_minor] = NULL;
        kfree (scn);
}

#ifdef SCN_IOCTL
static int
ioctl_scanner(struct inode *inode, struct file *file,
              unsigned int cmd, unsigned long arg)
{
        struct usb_device *dev;
        
        int result;

        kdev_t scn_minor;
        
        scn_minor = USB_SCN_MINOR(inode);

        if (!p_scn_table[scn_minor]) {
                err("ioctl_scanner(%d): invalid scn_minor", scn_minor);
                return -ENODEV;
        }

        dev = p_scn_table[scn_minor]->scn_dev;
        
        switch (cmd)
        {
        case PV8630_IOCTL_INREQUEST :
        {
                struct {
                        __u8  data;
                        __u8  request;
                        __u16 value;
                        __u16 index;
                } args;
                
                if (copy_from_user(&args, (void *)arg, sizeof(args)))
                        return -EFAULT;
                
                result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                                         args.request, USB_TYPE_VENDOR|
                                         USB_RECIP_DEVICE|USB_DIR_IN,
                                         args.value, args.index, &args.data,
                                         1, HZ*5);

                dbg("ioctl_scanner(%d): inreq: args.data:%x args.value:%x args.index:%x args.request:%x\n", scn_minor, args.data, args.value, args.index, args.request);

                if (copy_to_user((void *)arg, &args, sizeof(args)))
                        return -EFAULT;

                dbg("ioctl_scanner(%d): inreq: result:%d\n", scn_minor, result);
                
                return result;
        }
        case PV8630_IOCTL_OUTREQUEST :
        {
                struct {
                        __u8  request;
                        __u16 value;
                        __u16 index;
                } args;
                
                if (copy_from_user(&args, (void *)arg, sizeof(args)))
                        return -EFAULT;
                
                dbg("ioctl_scanner(%d): outreq: args.value:%x args.index:%x args.request:%x\n", scn_minor, args.value, args.index, args.request);

                result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                         args.request, USB_TYPE_VENDOR|
                                         USB_RECIP_DEVICE|USB_DIR_OUT,
                                         args.value, args.index, NULL,
                                         0, HZ*5);

                dbg("ioctl_scanner(%d): outreq: result:%d\n", scn_minor, result);
                
                return result;
        }
        default:
                return -ENOIOCTLCMD;
        }
        return 0;
}
#endif /* SCN_IOCTL */

static struct
file_operations usb_scanner_fops = {
        read:           read_scanner,
        write:          write_scanner,
#ifdef SCN_IOCTL
        ioctl:          ioctl_scanner,
#endif /* SCN_IOCTL */
        open:           open_scanner,
        release:        close_scanner,
};

static struct
usb_driver scanner_driver = {
       "usbscanner",
       probe_scanner,
       disconnect_scanner,
       { NULL, NULL },
       &usb_scanner_fops,
       SCN_BASE_MNR
};

void __exit
usb_scanner_exit(void)
{
        usb_deregister(&scanner_driver);
}

int __init
usb_scanner_init (void)
{
        if (usb_register(&scanner_driver) < 0)
                return -1;

        info("USB Scanner support registered.");
        return 0;
}

module_init(usb_scanner_init);
module_exit(usb_scanner_exit);