linux/drivers/media/video/cpia_usb.c
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   1/*
   2 * cpia_usb CPiA USB driver
   3 *
   4 * Supports CPiA based parallel port Video Camera's.
   5 *
   6 * Copyright (C) 1999        Jochen Scharrlach <Jochen.Scharrlach@schwaben.de>
   7 * Copyright (C) 1999, 2000  Johannes Erdfelt <johannes@erdfelt.com>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2 of the License, or
  12 * (at your option) any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful,
  15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 * GNU General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24/* define _CPIA_DEBUG_ for verbose debug output (see cpia.h) */
  25/* #define _CPIA_DEBUG_  1 */
  26
  27#include <linux/module.h>
  28#include <linux/kernel.h>
  29#include <linux/init.h>
  30#include <linux/wait.h>
  31#include <linux/list.h>
  32#include <linux/slab.h>
  33#include <linux/vmalloc.h>
  34#include <linux/usb.h>
  35
  36#include "cpia.h"
  37
  38#define USB_REQ_CPIA_GRAB_FRAME                 0xC1
  39#define USB_REQ_CPIA_UPLOAD_FRAME               0xC2
  40#define  WAIT_FOR_NEXT_FRAME                    0
  41#define  FORCE_FRAME_UPLOAD                     1
  42
  43#define FRAMES_PER_DESC         10
  44#define FRAME_SIZE_PER_DESC     960     /* Shouldn't be hardcoded */
  45#define CPIA_NUMSBUF            2
  46#define STREAM_BUF_SIZE         (PAGE_SIZE * 4)
  47#define SCRATCH_BUF_SIZE        (STREAM_BUF_SIZE * 2)
  48
  49struct cpia_sbuf {
  50        char *data;
  51        struct urb *urb;
  52};
  53
  54#define FRAMEBUF_LEN (CPIA_MAX_FRAME_SIZE+100)
  55enum framebuf_status {
  56        FRAME_EMPTY,
  57        FRAME_READING,
  58        FRAME_READY,
  59        FRAME_ERROR,
  60};
  61
  62struct framebuf {
  63        int length;
  64        enum framebuf_status status;
  65        u8 data[FRAMEBUF_LEN];
  66        struct framebuf *next;
  67};
  68
  69struct usb_cpia {
  70        /* Device structure */
  71        struct usb_device *dev;
  72
  73        unsigned char iface;
  74        wait_queue_head_t wq_stream;
  75
  76        int cursbuf;            /* Current receiving sbuf */
  77        struct cpia_sbuf sbuf[CPIA_NUMSBUF];            /* Double buffering */
  78
  79        int streaming;
  80        int open;
  81        int present;
  82        struct framebuf *buffers[3];
  83        struct framebuf *curbuff, *workbuff;
  84};
  85
  86static int cpia_usb_open(void *privdata);
  87static int cpia_usb_registerCallback(void *privdata, void (*cb) (void *cbdata),
  88                                     void *cbdata);
  89static int cpia_usb_transferCmd(void *privdata, u8 *command, u8 *data);
  90static int cpia_usb_streamStart(void *privdata);
  91static int cpia_usb_streamStop(void *privdata);
  92static int cpia_usb_streamRead(void *privdata, u8 *frame, int noblock);
  93static int cpia_usb_close(void *privdata);
  94
  95#define ABOUT "USB driver for Vision CPiA based cameras"
  96
  97static struct cpia_camera_ops cpia_usb_ops = {
  98        cpia_usb_open,
  99        cpia_usb_registerCallback,
 100        cpia_usb_transferCmd,
 101        cpia_usb_streamStart,
 102        cpia_usb_streamStop,
 103        cpia_usb_streamRead,
 104        cpia_usb_close,
 105        0,
 106        THIS_MODULE
 107};
 108
 109static LIST_HEAD(cam_list);
 110static spinlock_t cam_list_lock_usb;
 111
 112static void cpia_usb_complete(struct urb *urb)
 113{
 114        int i;
 115        char *cdata;
 116        struct usb_cpia *ucpia;
 117
 118        if (!urb || !urb->context)
 119                return;
 120
 121        ucpia = (struct usb_cpia *) urb->context;
 122
 123        if (!ucpia->dev || !ucpia->streaming || !ucpia->present || !ucpia->open)
 124                return;
 125
 126        if (ucpia->workbuff->status == FRAME_EMPTY) {
 127                ucpia->workbuff->status = FRAME_READING;
 128                ucpia->workbuff->length = 0;
 129        }
 130
 131        for (i = 0; i < urb->number_of_packets; i++) {
 132                int n = urb->iso_frame_desc[i].actual_length;
 133                int st = urb->iso_frame_desc[i].status;
 134
 135                cdata = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
 136
 137                if (st)
 138                        printk(KERN_DEBUG "cpia data error: [%d] len=%d, status=%X\n", i, n, st);
 139
 140                if (FRAMEBUF_LEN < ucpia->workbuff->length + n) {
 141                        printk(KERN_DEBUG "cpia: scratch buf overflow!scr_len: %d, n: %d\n", ucpia->workbuff->length, n);
 142                        return;
 143                }
 144
 145                if (n) {
 146                        if ((ucpia->workbuff->length > 0) ||
 147                            (0x19 == cdata[0] && 0x68 == cdata[1])) {
 148                                memcpy(ucpia->workbuff->data + ucpia->workbuff->length, cdata, n);
 149                                ucpia->workbuff->length += n;
 150                        } else
 151                                DBG("Ignoring packet!\n");
 152                } else {
 153                        if (ucpia->workbuff->length > 4 &&
 154                            0xff == ucpia->workbuff->data[ucpia->workbuff->length-1] &&
 155                            0xff == ucpia->workbuff->data[ucpia->workbuff->length-2] &&
 156                            0xff == ucpia->workbuff->data[ucpia->workbuff->length-3] &&
 157                            0xff == ucpia->workbuff->data[ucpia->workbuff->length-4]) {
 158                                ucpia->workbuff->status = FRAME_READY;
 159                                ucpia->curbuff = ucpia->workbuff;
 160                                ucpia->workbuff = ucpia->workbuff->next;
 161                                ucpia->workbuff->status = FRAME_EMPTY;
 162                                ucpia->workbuff->length = 0;
 163
 164                                if (waitqueue_active(&ucpia->wq_stream))
 165                                        wake_up_interruptible(&ucpia->wq_stream);
 166                        }
 167                }
 168        }
 169
 170        /* resubmit */
 171        urb->dev = ucpia->dev;
 172        if ((i = usb_submit_urb(urb, GFP_ATOMIC)) != 0)
 173                printk(KERN_ERR "%s: usb_submit_urb ret %d\n", __func__,  i);
 174}
 175
 176static int cpia_usb_open(void *privdata)
 177{
 178        struct usb_cpia *ucpia = (struct usb_cpia *) privdata;
 179        struct urb *urb;
 180        int ret, retval = 0, fx, err;
 181
 182        if (!ucpia)
 183                return -EINVAL;
 184
 185        ucpia->sbuf[0].data = kmalloc(FRAMES_PER_DESC * FRAME_SIZE_PER_DESC, GFP_KERNEL);
 186        if (!ucpia->sbuf[0].data)
 187                return -EINVAL;
 188
 189        ucpia->sbuf[1].data = kmalloc(FRAMES_PER_DESC * FRAME_SIZE_PER_DESC, GFP_KERNEL);
 190        if (!ucpia->sbuf[1].data) {
 191                retval = -EINVAL;
 192                goto error_0;
 193        }
 194
 195        ret = usb_set_interface(ucpia->dev, ucpia->iface, 3);
 196        if (ret < 0) {
 197                printk(KERN_ERR "cpia_usb_open: usb_set_interface error (ret = %d)\n", ret);
 198                retval = -EBUSY;
 199                goto error_1;
 200        }
 201
 202        ucpia->buffers[0]->status = FRAME_EMPTY;
 203        ucpia->buffers[0]->length = 0;
 204        ucpia->buffers[1]->status = FRAME_EMPTY;
 205        ucpia->buffers[1]->length = 0;
 206        ucpia->buffers[2]->status = FRAME_EMPTY;
 207        ucpia->buffers[2]->length = 0;
 208        ucpia->curbuff = ucpia->buffers[0];
 209        ucpia->workbuff = ucpia->buffers[1];
 210
 211        /* We double buffer the Iso lists, and also know the polling
 212         * interval is every frame (1 == (1 << (bInterval -1))).
 213         */
 214        urb = usb_alloc_urb(FRAMES_PER_DESC, GFP_KERNEL);
 215        if (!urb) {
 216                printk(KERN_ERR "cpia_init_isoc: usb_alloc_urb 0\n");
 217                retval = -ENOMEM;
 218                goto error_1;
 219        }
 220
 221        ucpia->sbuf[0].urb = urb;
 222        urb->dev = ucpia->dev;
 223        urb->context = ucpia;
 224        urb->pipe = usb_rcvisocpipe(ucpia->dev, 1);
 225        urb->transfer_flags = URB_ISO_ASAP;
 226        urb->transfer_buffer = ucpia->sbuf[0].data;
 227        urb->complete = cpia_usb_complete;
 228        urb->number_of_packets = FRAMES_PER_DESC;
 229        urb->interval = 1;
 230        urb->transfer_buffer_length = FRAME_SIZE_PER_DESC * FRAMES_PER_DESC;
 231        for (fx = 0; fx < FRAMES_PER_DESC; fx++) {
 232                urb->iso_frame_desc[fx].offset = FRAME_SIZE_PER_DESC * fx;
 233                urb->iso_frame_desc[fx].length = FRAME_SIZE_PER_DESC;
 234        }
 235
 236        urb = usb_alloc_urb(FRAMES_PER_DESC, GFP_KERNEL);
 237        if (!urb) {
 238                printk(KERN_ERR "cpia_init_isoc: usb_alloc_urb 1\n");
 239                retval = -ENOMEM;
 240                goto error_urb0;
 241        }
 242
 243        ucpia->sbuf[1].urb = urb;
 244        urb->dev = ucpia->dev;
 245        urb->context = ucpia;
 246        urb->pipe = usb_rcvisocpipe(ucpia->dev, 1);
 247        urb->transfer_flags = URB_ISO_ASAP;
 248        urb->transfer_buffer = ucpia->sbuf[1].data;
 249        urb->complete = cpia_usb_complete;
 250        urb->number_of_packets = FRAMES_PER_DESC;
 251        urb->interval = 1;
 252        urb->transfer_buffer_length = FRAME_SIZE_PER_DESC * FRAMES_PER_DESC;
 253        for (fx = 0; fx < FRAMES_PER_DESC; fx++) {
 254                urb->iso_frame_desc[fx].offset = FRAME_SIZE_PER_DESC * fx;
 255                urb->iso_frame_desc[fx].length = FRAME_SIZE_PER_DESC;
 256        }
 257
 258        /* queue the ISO urbs, and resubmit in the completion handler */
 259        err = usb_submit_urb(ucpia->sbuf[0].urb, GFP_KERNEL);
 260        if (err) {
 261                printk(KERN_ERR "cpia_init_isoc: usb_submit_urb 0 ret %d\n",
 262                        err);
 263                goto error_urb1;
 264        }
 265        err = usb_submit_urb(ucpia->sbuf[1].urb, GFP_KERNEL);
 266        if (err) {
 267                printk(KERN_ERR "cpia_init_isoc: usb_submit_urb 1 ret %d\n",
 268                        err);
 269                goto error_urb1;
 270        }
 271
 272        ucpia->streaming = 1;
 273        ucpia->open = 1;
 274
 275        return 0;
 276
 277error_urb1:             /* free urb 1 */
 278        usb_free_urb(ucpia->sbuf[1].urb);
 279        ucpia->sbuf[1].urb = NULL;
 280error_urb0:             /* free urb 0 */
 281        usb_free_urb(ucpia->sbuf[0].urb);
 282        ucpia->sbuf[0].urb = NULL;
 283error_1:
 284        kfree (ucpia->sbuf[1].data);
 285        ucpia->sbuf[1].data = NULL;
 286error_0:
 287        kfree (ucpia->sbuf[0].data);
 288        ucpia->sbuf[0].data = NULL;
 289
 290        return retval;
 291}
 292
 293//
 294// convenience functions
 295//
 296
 297/****************************************************************************
 298 *
 299 *  WritePacket
 300 *
 301 ***************************************************************************/
 302static int WritePacket(struct usb_device *udev, const u8 *packet, u8 *buf, size_t size)
 303{
 304        if (!packet)
 305                return -EINVAL;
 306
 307        return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
 308                         packet[1] + (packet[0] << 8),
 309                         USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 310                         packet[2] + (packet[3] << 8),
 311                         packet[4] + (packet[5] << 8), buf, size, 1000);
 312}
 313
 314/****************************************************************************
 315 *
 316 *  ReadPacket
 317 *
 318 ***************************************************************************/
 319static int ReadPacket(struct usb_device *udev, u8 *packet, u8 *buf, size_t size)
 320{
 321        if (!packet || size <= 0)
 322                return -EINVAL;
 323
 324        return usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
 325                         packet[1] + (packet[0] << 8),
 326                         USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 327                         packet[2] + (packet[3] << 8),
 328                         packet[4] + (packet[5] << 8), buf, size, 1000);
 329}
 330
 331static int cpia_usb_transferCmd(void *privdata, u8 *command, u8 *data)
 332{
 333        int err = 0;
 334        int databytes;
 335        struct usb_cpia *ucpia = (struct usb_cpia *)privdata;
 336        struct usb_device *udev = ucpia->dev;
 337
 338        if (!udev) {
 339                DBG("Internal driver error: udev is NULL\n");
 340                return -EINVAL;
 341        }
 342
 343        if (!command) {
 344                DBG("Internal driver error: command is NULL\n");
 345                return -EINVAL;
 346        }
 347
 348        databytes = (((int)command[7])<<8) | command[6];
 349
 350        if (command[0] == DATA_IN) {
 351                u8 buffer[8];
 352
 353                if (!data) {
 354                        DBG("Internal driver error: data is NULL\n");
 355                        return -EINVAL;
 356                }
 357
 358                err = ReadPacket(udev, command, buffer, 8);
 359                if (err < 0)
 360                        return err;
 361
 362                memcpy(data, buffer, databytes);
 363        } else if(command[0] == DATA_OUT)
 364                WritePacket(udev, command, data, databytes);
 365        else {
 366                DBG("Unexpected first byte of command: %x\n", command[0]);
 367                err = -EINVAL;
 368        }
 369
 370        return 0;
 371}
 372
 373static int cpia_usb_registerCallback(void *privdata, void (*cb) (void *cbdata),
 374        void *cbdata)
 375{
 376        return -ENODEV;
 377}
 378
 379static int cpia_usb_streamStart(void *privdata)
 380{
 381        return -ENODEV;
 382}
 383
 384static int cpia_usb_streamStop(void *privdata)
 385{
 386        return -ENODEV;
 387}
 388
 389static int cpia_usb_streamRead(void *privdata, u8 *frame, int noblock)
 390{
 391        struct usb_cpia *ucpia = (struct usb_cpia *) privdata;
 392        struct framebuf *mybuff;
 393
 394        if (!ucpia || !ucpia->present)
 395                return -1;
 396
 397        if (ucpia->curbuff->status != FRAME_READY)
 398                interruptible_sleep_on(&ucpia->wq_stream);
 399        else
 400                DBG("Frame already waiting!\n");
 401
 402        mybuff = ucpia->curbuff;
 403
 404        if (!mybuff)
 405                return -1;
 406
 407        if (mybuff->status != FRAME_READY || mybuff->length < 4) {
 408                DBG("Something went wrong!\n");
 409                return -1;
 410        }
 411
 412        memcpy(frame, mybuff->data, mybuff->length);
 413        mybuff->status = FRAME_EMPTY;
 414
 415/*   DBG("read done, %d bytes, Header: %x/%x, Footer: %x%x%x%x\n",  */
 416/*       mybuff->length, frame[0], frame[1], */
 417/*       frame[mybuff->length-4], frame[mybuff->length-3],  */
 418/*       frame[mybuff->length-2], frame[mybuff->length-1]); */
 419
 420        return mybuff->length;
 421}
 422
 423static void cpia_usb_free_resources(struct usb_cpia *ucpia, int try)
 424{
 425        if (!ucpia->streaming)
 426                return;
 427
 428        ucpia->streaming = 0;
 429
 430        /* Set packet size to 0 */
 431        if (try) {
 432                int ret;
 433
 434                ret = usb_set_interface(ucpia->dev, ucpia->iface, 0);
 435                if (ret < 0) {
 436                        printk(KERN_ERR "usb_set_interface error (ret = %d)\n", ret);
 437                        return;
 438                }
 439        }
 440
 441        /* Unschedule all of the iso td's */
 442        if (ucpia->sbuf[1].urb) {
 443                usb_kill_urb(ucpia->sbuf[1].urb);
 444                usb_free_urb(ucpia->sbuf[1].urb);
 445                ucpia->sbuf[1].urb = NULL;
 446        }
 447
 448        kfree(ucpia->sbuf[1].data);
 449        ucpia->sbuf[1].data = NULL;
 450
 451        if (ucpia->sbuf[0].urb) {
 452                usb_kill_urb(ucpia->sbuf[0].urb);
 453                usb_free_urb(ucpia->sbuf[0].urb);
 454                ucpia->sbuf[0].urb = NULL;
 455        }
 456
 457        kfree(ucpia->sbuf[0].data);
 458        ucpia->sbuf[0].data = NULL;
 459}
 460
 461static int cpia_usb_close(void *privdata)
 462{
 463        struct usb_cpia *ucpia = (struct usb_cpia *) privdata;
 464
 465        if(!ucpia)
 466                return -ENODEV;
 467
 468        ucpia->open = 0;
 469
 470        /* ucpia->present = 0 protects against trying to reset the
 471         * alt setting if camera is physically disconnected while open */
 472        cpia_usb_free_resources(ucpia, ucpia->present);
 473
 474        return 0;
 475}
 476
 477/* Probing and initializing */
 478
 479static int cpia_probe(struct usb_interface *intf,
 480                      const struct usb_device_id *id)
 481{
 482        struct usb_device *udev = interface_to_usbdev(intf);
 483        struct usb_host_interface *interface;
 484        struct usb_cpia *ucpia;
 485        struct cam_data *cam;
 486        int ret;
 487
 488        /* A multi-config CPiA camera? */
 489        if (udev->descriptor.bNumConfigurations != 1)
 490                return -ENODEV;
 491
 492        interface = intf->cur_altsetting;
 493
 494        printk(KERN_INFO "USB CPiA camera found\n");
 495
 496        ucpia = kzalloc(sizeof(*ucpia), GFP_KERNEL);
 497        if (!ucpia) {
 498                printk(KERN_ERR "couldn't kmalloc cpia struct\n");
 499                return -ENOMEM;
 500        }
 501
 502        ucpia->dev = udev;
 503        ucpia->iface = interface->desc.bInterfaceNumber;
 504        init_waitqueue_head(&ucpia->wq_stream);
 505
 506        ucpia->buffers[0] = vmalloc(sizeof(*ucpia->buffers[0]));
 507        if (!ucpia->buffers[0]) {
 508                printk(KERN_ERR "couldn't vmalloc frame buffer 0\n");
 509                goto fail_alloc_0;
 510        }
 511
 512        ucpia->buffers[1] = vmalloc(sizeof(*ucpia->buffers[1]));
 513        if (!ucpia->buffers[1]) {
 514                printk(KERN_ERR "couldn't vmalloc frame buffer 1\n");
 515                goto fail_alloc_1;
 516        }
 517
 518        ucpia->buffers[2] = vmalloc(sizeof(*ucpia->buffers[2]));
 519        if (!ucpia->buffers[2]) {
 520                printk(KERN_ERR "couldn't vmalloc frame buffer 2\n");
 521                goto fail_alloc_2;
 522        }
 523
 524        ucpia->buffers[0]->next = ucpia->buffers[1];
 525        ucpia->buffers[1]->next = ucpia->buffers[2];
 526        ucpia->buffers[2]->next = ucpia->buffers[0];
 527
 528        ret = usb_set_interface(udev, ucpia->iface, 0);
 529        if (ret < 0) {
 530                printk(KERN_ERR "cpia_probe: usb_set_interface error (ret = %d)\n", ret);
 531                /* goto fail_all; */
 532        }
 533
 534        /* Before register_camera, important */
 535        ucpia->present = 1;
 536
 537        cam = cpia_register_camera(&cpia_usb_ops, ucpia);
 538        if (!cam) {
 539                LOG("failed to cpia_register_camera\n");
 540                goto fail_all;
 541        }
 542
 543        spin_lock( &cam_list_lock_usb );
 544        list_add( &cam->cam_data_list, &cam_list );
 545        spin_unlock( &cam_list_lock_usb );
 546
 547        usb_set_intfdata(intf, cam);
 548        return 0;
 549
 550fail_all:
 551        vfree(ucpia->buffers[2]);
 552        ucpia->buffers[2] = NULL;
 553fail_alloc_2:
 554        vfree(ucpia->buffers[1]);
 555        ucpia->buffers[1] = NULL;
 556fail_alloc_1:
 557        vfree(ucpia->buffers[0]);
 558        ucpia->buffers[0] = NULL;
 559fail_alloc_0:
 560        kfree(ucpia);
 561        return -EIO;
 562}
 563
 564static void cpia_disconnect(struct usb_interface *intf);
 565
 566static struct usb_device_id cpia_id_table [] = {
 567        { USB_DEVICE(0x0553, 0x0002) },
 568        { USB_DEVICE(0x0813, 0x0001) },
 569        { }                                     /* Terminating entry */
 570};
 571
 572MODULE_DEVICE_TABLE (usb, cpia_id_table);
 573MODULE_LICENSE("GPL");
 574
 575
 576static struct usb_driver cpia_driver = {
 577        .name           = "cpia",
 578        .probe          = cpia_probe,
 579        .disconnect     = cpia_disconnect,
 580        .id_table       = cpia_id_table,
 581};
 582
 583static void cpia_disconnect(struct usb_interface *intf)
 584{
 585        struct cam_data *cam = usb_get_intfdata(intf);
 586        struct usb_cpia *ucpia;
 587        struct usb_device *udev;
 588
 589        usb_set_intfdata(intf, NULL);
 590        if (!cam)
 591                return;
 592
 593        ucpia = (struct usb_cpia *) cam->lowlevel_data;
 594        spin_lock( &cam_list_lock_usb );
 595        list_del(&cam->cam_data_list);
 596        spin_unlock( &cam_list_lock_usb );
 597
 598        ucpia->present = 0;
 599
 600        cpia_unregister_camera(cam);
 601        if(ucpia->open)
 602                cpia_usb_close(cam->lowlevel_data);
 603
 604        ucpia->curbuff->status = FRAME_ERROR;
 605
 606        if (waitqueue_active(&ucpia->wq_stream))
 607                wake_up_interruptible(&ucpia->wq_stream);
 608
 609        udev = interface_to_usbdev(intf);
 610
 611        ucpia->curbuff = ucpia->workbuff = NULL;
 612
 613        vfree(ucpia->buffers[2]);
 614        ucpia->buffers[2] = NULL;
 615
 616        vfree(ucpia->buffers[1]);
 617        ucpia->buffers[1] = NULL;
 618
 619        vfree(ucpia->buffers[0]);
 620        ucpia->buffers[0] = NULL;
 621
 622        cam->lowlevel_data = NULL;
 623        kfree(ucpia);
 624}
 625
 626static int __init usb_cpia_init(void)
 627{
 628        printk(KERN_INFO "%s v%d.%d.%d\n",ABOUT,
 629               CPIA_USB_MAJ_VER,CPIA_USB_MIN_VER,CPIA_USB_PATCH_VER);
 630
 631        spin_lock_init(&cam_list_lock_usb);
 632        return usb_register(&cpia_driver);
 633}
 634
 635static void __exit usb_cpia_cleanup(void)
 636{
 637        usb_deregister(&cpia_driver);
 638}
 639
 640
 641module_init (usb_cpia_init);
 642module_exit (usb_cpia_cleanup);
 643
 644