git.oblomov.eu Git - linux-2.6/blob - drivers/staging/frontier/alphatrack.c

   1 /*
   2  * Frontier Designs Alphatrack driver
   3  *
   4  * Copyright (C) 2007 Michael Taht (m@taht.net)
   5  *
   6  * Based on the usbled driver and ldusb drivers by
   7  *
   8  * Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com)
   9  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
  10  *
  11  * The ldusb driver was, in turn, derived from Lego USB Tower driver
  12  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
  13  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
  14  *
  15  *      This program is free software; you can redistribute it and/or
  16  *      modify it under the terms of the GNU General Public License as
  17  *      published by the Free Software Foundation, version 2.
  18  *
  19  */
  20
  21 /**
  22  * This driver uses a ring buffer for time critical reading of
  23  * interrupt in reports and provides read and write methods for
  24  * raw interrupt reports.
  25  */
  26
  27 /* Note: this currently uses a dumb ringbuffer for reads and writes.
  28  * A more optimal driver would cache and kill off outstanding urbs that are
  29  * now invalid, and ignore ones that already were in the queue but valid
  30  * as we only have 30 commands for the alphatrack. In particular this is
  31  * key for getting lights to flash in time as otherwise many commands
  32  * can be buffered up before the light change makes it to the interface.
  33 */
  34
  35 #include <linux/kernel.h>
  36 #include <linux/errno.h>
  37 #include <linux/init.h>
  38 #include <linux/slab.h>
  39 #include <linux/module.h>
  40 #include <linux/kobject.h>
  41 #include <linux/mutex.h>
  42
  43 #include <linux/uaccess.h>
  44 #include <linux/input.h>
  45 #include <linux/usb.h>
  46 #include <linux/poll.h>
  47
  48 #include "alphatrack.h"
  49
  50 #define VENDOR_ID       0x165b
  51 #define PRODUCT_ID      0xfad1
  52
  53 #ifdef CONFIG_USB_DYNAMIC_MINORS
  54 #define USB_ALPHATRACK_MINOR_BASE       0
  55 #else
  56 /* FIXME 176 - is another driver's minor - apply for that */
  57 #define USB_ALPHATRACK_MINOR_BASE       176
  58 #endif
  59
  60 /* table of devices that work with this driver */
  61 static struct usb_device_id usb_alphatrack_table[] = {
  62         {USB_DEVICE(VENDOR_ID, PRODUCT_ID)},
  63         {}                      /* Terminating entry */
  64 };
  65
  66 MODULE_DEVICE_TABLE(usb, usb_alphatrack_table);
  67 MODULE_VERSION("0.41");
  68 MODULE_AUTHOR("Mike Taht <m@taht.net>");
  69 MODULE_DESCRIPTION("Alphatrack USB Driver");
  70 MODULE_LICENSE("GPL");
  71 MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface");
  72
  73 /* These aren't done yet */
  74
  75 #define SUPPRESS_EXTRA_ONLINE_EVENTS 0
  76 #define BUFFERED_WRITES 0
  77 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0
  78 #define COMPRESS_FADER_EVENTS 0
  79
  80 #define BUFFERED_READS 1
  81 #define RING_BUFFER_SIZE 512
  82 #define WRITE_BUFFER_SIZE 34
  83 #define ALPHATRACK_USB_TIMEOUT 10
  84 #define OUTPUT_CMD_SIZE 8
  85 #define INPUT_CMD_SIZE 12
  86 #define ALPHATRACK_DEBUG 0
  87
  88 static int debug = ALPHATRACK_DEBUG;
  89
  90 /* Use our own dbg macro */
  91 #define dbg_info(dev, format, arg...) do \
  92     { if (debug) dev_info(dev , format , ## arg); } while (0)
  93
  94 #define alphatrack_ocmd_info(dev, cmd, format, arg...)
  95
  96 #define alphatrack_icmd_info(dev, cmd, format, arg...)
  97
  98 /* Module parameters */
  99
 100 module_param(debug, int, S_IRUGO | S_IWUSR);
 101 MODULE_PARM_DESC(debug, "Debug enabled or not");
 102
 103 /* All interrupt in transfers are collected in a ring buffer to
 104  * avoid racing conditions and get better performance of the driver.
 105  */
 106
 107 static int ring_buffer_size = RING_BUFFER_SIZE;
 108
 109 module_param(ring_buffer_size, int, S_IRUGO);
 110 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
 111
 112 /* The write_buffer can one day contain more than one interrupt out transfer.
 113  */
 114
 115 static int write_buffer_size = WRITE_BUFFER_SIZE;
 116 module_param(write_buffer_size, int, S_IRUGO);
 117 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 118
 119 /*
 120  * Increase the interval for debugging purposes.
 121  * or set to 1 to use the standard interval from the endpoint descriptors.
 122  */
 123
 124 static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT;
 125 module_param(min_interrupt_in_interval, int, 0);
 126 MODULE_PARM_DESC(min_interrupt_in_interval,
 127                  "Minimum interrupt in interval in ms");
 128
 129 static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT;
 130 module_param(min_interrupt_out_interval, int, 0);
 131 MODULE_PARM_DESC(min_interrupt_out_interval,
 132                  "Minimum interrupt out interval in ms");
 133
 134 /* Structure to hold all of our device specific stuff */
 135
 136 struct usb_alphatrack {
 137         struct semaphore sem;   /* locks this structure */
 138         struct usb_interface *intf;     /* save off the usb interface pointer */
 139         int open_count;         /* number of times this port has been opened */
 140
 141         /* make gcc happy */
 142         struct alphatrack_icmd (*ring_buffer)[RING_BUFFER_SIZE];
 143         struct alphatrack_ocmd (*write_buffer)[WRITE_BUFFER_SIZE];
 144         unsigned int ring_head;
 145         unsigned int ring_tail;
 146
 147         wait_queue_head_t read_wait;
 148         wait_queue_head_t write_wait;
 149
 150         unsigned char *interrupt_in_buffer;
 151         unsigned char *oldi_buffer;
 152         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 153         struct urb *interrupt_in_urb;
 154         int interrupt_in_interval;
 155         size_t interrupt_in_endpoint_size;
 156         int interrupt_in_running;
 157         int interrupt_in_done;
 158
 159         char *interrupt_out_buffer;
 160         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 161         struct urb *interrupt_out_urb;
 162         int interrupt_out_interval;
 163         size_t interrupt_out_endpoint_size;
 164         int interrupt_out_busy;
 165
 166         atomic_t writes_pending;
 167         int event;              /* alternate interface to events */
 168         int fader;              /* 10 bits */
 169         int lights;             /* 23 bits */
 170         unsigned char dump_state;       /* 0 if disabled 1 if enabled */
 171         unsigned char enable;   /* 0 if disabled 1 if enabled */
 172         unsigned char offline;  /* if the device is out of range or asleep */
 173         unsigned char verbose;  /* be verbose in error reporting */
 174         unsigned char last_cmd[OUTPUT_CMD_SIZE];
 175         unsigned char screen[32];
 176 };
 177
 178 /* prevent races between open() and disconnect() */
 179 static DEFINE_MUTEX(disconnect_mutex);
 180
 181 /* forward declaration */
 182
 183 static struct usb_driver usb_alphatrack_driver;
 184
 185 /**
 186  *      usb_alphatrack_abort_transfers
 187  *      aborts transfers and frees associated data structures
 188  */
 189 static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev)
 190 {
 191         /* shutdown transfer */
 192         if (dev->interrupt_in_running) {
 193                 dev->interrupt_in_running = 0;
 194                 if (dev->intf)
 195                         usb_kill_urb(dev->interrupt_in_urb);
 196         }
 197         if (dev->interrupt_out_busy)
 198                 if (dev->intf)
 199                         usb_kill_urb(dev->interrupt_out_urb);
 200 }
 201
 202 /**
 203  *      usb_alphatrack_delete
 204  */
 205 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
 206 {
 207         usb_alphatrack_abort_transfers(dev);
 208         usb_free_urb(dev->interrupt_in_urb);
 209         usb_free_urb(dev->interrupt_out_urb);
 210         kfree(dev->ring_buffer);
 211         kfree(dev->interrupt_in_buffer);
 212         kfree(dev->interrupt_out_buffer);
 213         kfree(dev);             /* fixme oldi_buffer */
 214 }
 215
 216 /**
 217  *      usb_alphatrack_interrupt_in_callback
 218  */
 219
 220 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
 221 {
 222         struct usb_alphatrack *dev = urb->context;
 223         unsigned int next_ring_head;
 224         int retval = -1;
 225
 226         if (urb->status) {
 227                 if (urb->status == -ENOENT ||
 228                     urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) {
 229                         goto exit;
 230                 } else {
 231                         dbg_info(&dev->intf->dev,
 232                                  "%s: nonzero status received: %d\n", __func__,
 233                                  urb->status);
 234                         goto resubmit;  /* maybe we can recover */
 235                 }
 236         }
 237
 238         if (urb->actual_length != INPUT_CMD_SIZE) {
 239                 dev_warn(&dev->intf->dev,
 240                          "Urb length was %d bytes!!"
 241                          "Do something intelligent \n", urb->actual_length);
 242         } else {
 243                 alphatrack_ocmd_info(&dev->intf->dev,
 244                                      &(*dev->ring_buffer)[dev->ring_tail].cmd,
 245                                      "%s", "bla");
 246                 if (memcmp
 247                     (dev->interrupt_in_buffer, dev->oldi_buffer,
 248                      INPUT_CMD_SIZE) == 0) {
 249                         goto resubmit;
 250                 }
 251                 memcpy(dev->oldi_buffer, dev->interrupt_in_buffer,
 252                        INPUT_CMD_SIZE);
 253
 254 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 255                 if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
 256                         goto resubmit;
 257                 if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
 258                         dev->offline = 2;
 259                         goto resubmit;
 260                 }
 261 /* Always pass one offline event up the stack */
 262                 if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
 263                         dev->offline = 0;
 264                 if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
 265                         dev->offline = 1;
 266 #endif
 267                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 268                          __func__, dev->ring_head, dev->ring_tail);
 269                 next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
 270
 271                 if (next_ring_head != dev->ring_tail) {
 272                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 273                                dev->interrupt_in_buffer, urb->actual_length);
 274                         dev->ring_head = next_ring_head;
 275                         retval = 0;
 276                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 277                 } else {
 278                         dev_warn(&dev->intf->dev,
 279                                  "Ring buffer overflow, %d bytes dropped\n",
 280                                  urb->actual_length);
 281                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 282                 }
 283         }
 284
 285 resubmit:
 286         /* resubmit if we're still running */
 287         if (dev->interrupt_in_running && dev->intf) {
 288                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 289                 if (retval)
 290                         dev_err(&dev->intf->dev,
 291                                 "usb_submit_urb failed (%d)\n", retval);
 292         }
 293
 294 exit:
 295         dev->interrupt_in_done = 1;
 296         wake_up_interruptible(&dev->read_wait);
 297 }
 298
 299 /**
 300  *      usb_alphatrack_interrupt_out_callback
 301  */
 302 static void usb_alphatrack_interrupt_out_callback(struct urb *urb)
 303 {
 304         struct usb_alphatrack *dev = urb->context;
 305
 306         /* sync/async unlink faults aren't errors */
 307         if (urb->status && !(urb->status == -ENOENT ||
 308                              urb->status == -ECONNRESET ||
 309                              urb->status == -ESHUTDOWN))
 310                 dbg_info(&dev->intf->dev,
 311                          "%s - nonzero write interrupt status received: %d\n",
 312                          __func__, urb->status);
 313         atomic_dec(&dev->writes_pending);
 314         dev->interrupt_out_busy = 0;
 315         wake_up_interruptible(&dev->write_wait);
 316 }
 317
 318 /**
 319  *      usb_alphatrack_open
 320  */
 321 static int usb_alphatrack_open(struct inode *inode, struct file *file)
 322 {
 323         struct usb_alphatrack *dev;
 324         int subminor;
 325         int retval = 0;
 326         struct usb_interface *interface;
 327
 328         nonseekable_open(inode, file);
 329         subminor = iminor(inode);
 330
 331         mutex_lock(&disconnect_mutex);
 332
 333         interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 334
 335         if (!interface) {
 336                 err("%s - error, can't find device for minor %d\n",
 337                     __func__, subminor);
 338                 retval = -ENODEV;
 339                 goto unlock_disconnect_exit;
 340         }
 341
 342         dev = usb_get_intfdata(interface);
 343
 344         if (!dev) {
 345                 retval = -ENODEV;
 346                 goto unlock_disconnect_exit;
 347         }
 348
 349         /* lock this device */
 350         if (down_interruptible(&dev->sem)) {
 351                 retval = -ERESTARTSYS;
 352                 goto unlock_disconnect_exit;
 353         }
 354
 355         /* allow opening only once */
 356         if (dev->open_count) {
 357                 retval = -EBUSY;
 358                 goto unlock_exit;
 359         }
 360         dev->open_count = 1;
 361
 362         /* initialize in direction */
 363         dev->ring_head = 0;
 364         dev->ring_tail = 0;
 365         usb_fill_int_urb(dev->interrupt_in_urb,
 366                          interface_to_usbdev(interface),
 367                          usb_rcvintpipe(interface_to_usbdev(interface),
 368                                         dev->interrupt_in_endpoint->
 369                                         bEndpointAddress),
 370                          dev->interrupt_in_buffer,
 371                          dev->interrupt_in_endpoint_size,
 372                          usb_alphatrack_interrupt_in_callback, dev,
 373                          dev->interrupt_in_interval);
 374
 375         dev->interrupt_in_running = 1;
 376         dev->interrupt_in_done = 0;
 377         dev->enable = 1;
 378         dev->offline = 0;
 379
 380         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 381         if (retval) {
 382                 dev_err(&interface->dev,
 383                         "Couldn't submit interrupt_in_urb %d\n", retval);
 384                 dev->interrupt_in_running = 0;
 385                 dev->open_count = 0;
 386                 goto unlock_exit;
 387         }
 388
 389         /* save device in the file's private structure */
 390         file->private_data = dev;
 391
 392 unlock_exit:
 393         up(&dev->sem);
 394
 395 unlock_disconnect_exit:
 396         mutex_unlock(&disconnect_mutex);
 397
 398         return retval;
 399 }
 400
 401 /**
 402  *      usb_alphatrack_release
 403  */
 404 static int usb_alphatrack_release(struct inode *inode, struct file *file)
 405 {
 406         struct usb_alphatrack *dev;
 407         int retval = 0;
 408
 409         dev = file->private_data;
 410
 411         if (dev == NULL) {
 412                 retval = -ENODEV;
 413                 goto exit;
 414         }
 415
 416         if (down_interruptible(&dev->sem)) {
 417                 retval = -ERESTARTSYS;
 418                 goto exit;
 419         }
 420
 421         if (dev->open_count != 1) {
 422                 retval = -ENODEV;
 423                 goto unlock_exit;
 424         }
 425
 426         if (dev->intf == NULL) {
 427                 /* the device was unplugged before the file was released */
 428                 up(&dev->sem);
 429                 /* unlock here as usb_alphatrack_delete frees dev */
 430                 usb_alphatrack_delete(dev);
 431                 retval = -ENODEV;
 432                 goto exit;
 433         }
 434
 435         /* wait until write transfer is finished */
 436         if (dev->interrupt_out_busy)
 437                 wait_event_interruptible_timeout(dev->write_wait,
 438                                                  !dev->interrupt_out_busy,
 439                                                  2 * HZ);
 440         usb_alphatrack_abort_transfers(dev);
 441         dev->open_count = 0;
 442
 443 unlock_exit:
 444         up(&dev->sem);
 445
 446 exit:
 447         return retval;
 448 }
 449
 450 /**
 451  *      usb_alphatrack_poll
 452  */
 453 static unsigned int usb_alphatrack_poll(struct file *file, poll_table * wait)
 454 {
 455         struct usb_alphatrack *dev;
 456         unsigned int mask = 0;
 457
 458         dev = file->private_data;
 459
 460         poll_wait(file, &dev->read_wait, wait);
 461         poll_wait(file, &dev->write_wait, wait);
 462
 463         if (dev->ring_head != dev->ring_tail)
 464                 mask |= POLLIN | POLLRDNORM;
 465         if (!dev->interrupt_out_busy)
 466                 mask |= POLLOUT | POLLWRNORM;
 467
 468         return mask;
 469 }
 470
 471 /**
 472  *      usb_alphatrack_read
 473  */
 474 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer,
 475                                    size_t count, loff_t *ppos)
 476 {
 477         struct usb_alphatrack *dev;
 478         int retval = 0;
 479
 480         int c = 0;
 481
 482         dev = file->private_data;
 483
 484         /* verify that we actually have some data to read */
 485         if (count == 0)
 486                 goto exit;
 487
 488         /* lock this object */
 489         if (down_interruptible(&dev->sem)) {
 490                 retval = -ERESTARTSYS;
 491                 goto exit;
 492         }
 493
 494         /* verify that the device wasn't unplugged */
 495         if (dev->intf == NULL) {
 496                 retval = -ENODEV;
 497                 err("No device or device unplugged %d\n", retval);
 498                 goto unlock_exit;
 499         }
 500
 501         while (dev->ring_head == dev->ring_tail) {
 502                 if (file->f_flags & O_NONBLOCK) {
 503                         retval = -EAGAIN;
 504                         goto unlock_exit;
 505                 }
 506                 dev->interrupt_in_done = 0;
 507                 retval =
 508                     wait_event_interruptible(dev->read_wait,
 509                                              dev->interrupt_in_done);
 510                 if (retval < 0)
 511                         goto unlock_exit;
 512         }
 513
 514         alphatrack_ocmd_info(&dev->intf->dev,
 515                              &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s",
 516                              ": copying to userspace");
 517
 518         c = 0;
 519         while ((c < count) && (dev->ring_tail != dev->ring_head)) {
 520                 if (copy_to_user
 521                     (&buffer[c], &(*dev->ring_buffer)[dev->ring_tail],
 522                      INPUT_CMD_SIZE)) {
 523                         retval = -EFAULT;
 524                         goto unlock_exit;
 525                 }
 526                 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 527                 c += INPUT_CMD_SIZE;
 528                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 529                          __func__, dev->ring_head, dev->ring_tail);
 530         }
 531         retval = c;
 532
 533 unlock_exit:
 534         /* unlock the device */
 535         up(&dev->sem);
 536
 537 exit:
 538         return retval;
 539 }
 540
 541 /**
 542  *      usb_alphatrack_write
 543  */
 544 static ssize_t usb_alphatrack_write(struct file *file,
 545                                     const char __user *buffer, size_t count,
 546                                     loff_t *ppos)
 547 {
 548         struct usb_alphatrack *dev;
 549         size_t bytes_to_write;
 550         int retval = 0;
 551
 552         dev = file->private_data;
 553
 554         /* verify that we actually have some data to write */
 555         if (count == 0)
 556                 goto exit;
 557
 558         /* lock this object */
 559         if (down_interruptible(&dev->sem)) {
 560                 retval = -ERESTARTSYS;
 561                 goto exit;
 562         }
 563
 564         /* verify that the device wasn't unplugged */
 565         if (dev->intf == NULL) {
 566                 retval = -ENODEV;
 567                 err("No device or device unplugged %d\n", retval);
 568                 goto unlock_exit;
 569         }
 570
 571         /* wait until previous transfer is finished */
 572         if (dev->interrupt_out_busy) {
 573                 if (file->f_flags & O_NONBLOCK) {
 574                         retval = -EAGAIN;
 575                         goto unlock_exit;
 576                 }
 577                 retval =
 578                     wait_event_interruptible(dev->write_wait,
 579                                              !dev->interrupt_out_busy);
 580                 if (retval < 0)
 581                         goto unlock_exit;
 582         }
 583
 584         /* write the data into interrupt_out_buffer from userspace */
 585         /* FIXME - if you write more than 12 bytes this breaks */
 586         bytes_to_write =
 587             min(count, write_buffer_size * dev->interrupt_out_endpoint_size);
 588         if (bytes_to_write < count)
 589                 dev_warn(&dev->intf->dev,
 590                          "Write buffer overflow, %zd bytes dropped\n",
 591                          count - bytes_to_write);
 592
 593         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 594                  __func__, count, bytes_to_write);
 595
 596         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 597                 retval = -EFAULT;
 598                 goto unlock_exit;
 599         }
 600
 601         if (dev->interrupt_out_endpoint == NULL) {
 602                 err("Endpoint should not be be null! \n");
 603                 goto unlock_exit;
 604         }
 605
 606         /* send off the urb */
 607         usb_fill_int_urb(dev->interrupt_out_urb,
 608                          interface_to_usbdev(dev->intf),
 609                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 610                                         dev->interrupt_out_endpoint->
 611                                         bEndpointAddress),
 612                          dev->interrupt_out_buffer, bytes_to_write,
 613                          usb_alphatrack_interrupt_out_callback, dev,
 614                          dev->interrupt_out_interval);
 615         dev->interrupt_out_busy = 1;
 616         atomic_inc(&dev->writes_pending);
 617         wmb();
 618
 619         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 620         if (retval) {
 621                 dev->interrupt_out_busy = 0;
 622                 err("Couldn't submit interrupt_out_urb %d\n", retval);
 623                 atomic_dec(&dev->writes_pending);
 624                 goto unlock_exit;
 625         }
 626         retval = bytes_to_write;
 627
 628 unlock_exit:
 629         /* unlock the device */
 630         up(&dev->sem);
 631
 632 exit:
 633         return retval;
 634 }
 635
 636 /* file operations needed when we register this driver */
 637 static const struct file_operations usb_alphatrack_fops = {
 638         .owner = THIS_MODULE,
 639         .read = usb_alphatrack_read,
 640         .write = usb_alphatrack_write,
 641         .open = usb_alphatrack_open,
 642         .release = usb_alphatrack_release,
 643         .poll = usb_alphatrack_poll,
 644 };
 645
 646 /*
 647  * usb class driver info in order to get a minor number from the usb core,
 648  * and to have the device registered with the driver core
 649  */
 650
 651 static struct usb_class_driver usb_alphatrack_class = {
 652         .name = "alphatrack%d",
 653         .fops = &usb_alphatrack_fops,
 654         .minor_base = USB_ALPHATRACK_MINOR_BASE,
 655 };
 656
 657 /**
 658  *      usb_alphatrack_probe
 659  *
 660  *      Called by the usb core when a new device is connected that it thinks
 661  *      this driver might be interested in.
 662  */
 663 static int usb_alphatrack_probe(struct usb_interface *intf,
 664                                 const struct usb_device_id *id)
 665 {
 666         struct usb_device *udev = interface_to_usbdev(intf);
 667         struct usb_alphatrack *dev = NULL;
 668         struct usb_host_interface *iface_desc;
 669         struct usb_endpoint_descriptor *endpoint;
 670         int i;
 671         int true_size;
 672         int retval = -ENOMEM;
 673
 674         /* allocate memory for our device state and intialize it */
 675
 676         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 677         if (dev == NULL) {
 678                 dev_err(&intf->dev, "Out of memory\n");
 679                 goto exit;
 680         }
 681         init_MUTEX(&dev->sem);
 682         dev->intf = intf;
 683         init_waitqueue_head(&dev->read_wait);
 684         init_waitqueue_head(&dev->write_wait);
 685
 686         iface_desc = intf->cur_altsetting;
 687
 688         /* set up the endpoint information */
 689         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 690                 endpoint = &iface_desc->endpoint[i].desc;
 691
 692                 if (usb_endpoint_is_int_in(endpoint))
 693                         dev->interrupt_in_endpoint = endpoint;
 694
 695                 if (usb_endpoint_is_int_out(endpoint))
 696                         dev->interrupt_out_endpoint = endpoint;
 697         }
 698         if (dev->interrupt_in_endpoint == NULL) {
 699                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 700                 goto error;
 701         }
 702         if (dev->interrupt_out_endpoint == NULL)
 703                 dev_warn(&intf->dev,
 704                          "Interrupt out endpoint not found"
 705                          "(using control endpoint instead)\n");
 706
 707         dev->interrupt_in_endpoint_size =
 708             le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 709
 710         if (dev->interrupt_in_endpoint_size != 64)
 711                 dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
 712
 713         if (ring_buffer_size == 0)
 714                 ring_buffer_size = RING_BUFFER_SIZE;
 715
 716         true_size = min(ring_buffer_size, RING_BUFFER_SIZE);
 717
 718         /* FIXME - there are more usb_alloc routines for dma correctness.
 719            Needed? */
 720         dev->ring_buffer =
 721             kmalloc((true_size * sizeof(struct alphatrack_icmd)), GFP_KERNEL);
 722
 723         if (!dev->ring_buffer) {
 724                 dev_err(&intf->dev,
 725                         "Couldn't allocate input ring_buffer of size %d\n",
 726                         true_size);
 727                 goto error;
 728         }
 729
 730         dev->interrupt_in_buffer =
 731             kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 732
 733         if (!dev->interrupt_in_buffer) {
 734                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 735                 goto error;
 736         }
 737         dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 738         if (!dev->oldi_buffer) {
 739                 dev_err(&intf->dev, "Couldn't allocate old buffer\n");
 740                 goto error;
 741         }
 742         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 743         if (!dev->interrupt_in_urb) {
 744                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 745                 goto error;
 746         }
 747
 748         dev->interrupt_out_endpoint_size =
 749             dev->interrupt_out_endpoint ? le16_to_cpu(dev->
 750                                                       interrupt_out_endpoint->
 751                                                       wMaxPacketSize) : udev->
 752             descriptor.bMaxPacketSize0;
 753
 754         if (dev->interrupt_out_endpoint_size != 64)
 755                 dev_warn(&intf->dev,
 756                          "Interrupt out endpoint size is not 64!)\n");
 757
 758         if (write_buffer_size == 0)
 759                 write_buffer_size = WRITE_BUFFER_SIZE;
 760         true_size = min(write_buffer_size, WRITE_BUFFER_SIZE);
 761
 762         dev->interrupt_out_buffer =
 763             kmalloc(true_size * dev->interrupt_out_endpoint_size, GFP_KERNEL);
 764
 765         if (!dev->interrupt_out_buffer) {
 766                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 767                 goto error;
 768         }
 769
 770         dev->write_buffer =
 771             kmalloc(sizeof(struct alphatrack_ocmd) * true_size, GFP_KERNEL);
 772
 773         if (!dev->write_buffer) {
 774                 dev_err(&intf->dev, "Couldn't allocate write_buffer \n");
 775                 goto error;
 776         }
 777
 778         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 779         if (!dev->interrupt_out_urb) {
 780                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 781                 goto error;
 782         }
 783         dev->interrupt_in_interval =
 784             min_interrupt_in_interval >
 785             dev->interrupt_in_endpoint->
 786             bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->
 787             bInterval;
 788         if (dev->interrupt_out_endpoint)
 789                 dev->interrupt_out_interval =
 790                     min_interrupt_out_interval >
 791                     dev->interrupt_out_endpoint->
 792                     bInterval ? min_interrupt_out_interval : dev->
 793                     interrupt_out_endpoint->bInterval;
 794
 795         /* we can register the device now, as it is ready */
 796         usb_set_intfdata(intf, dev);
 797
 798         atomic_set(&dev->writes_pending, 0);
 799         retval = usb_register_dev(intf, &usb_alphatrack_class);
 800         if (retval) {
 801                 /* something prevented us from registering this driver */
 802                 dev_err(&intf->dev,
 803                         "Not able to get a minor for this device.\n");
 804                 usb_set_intfdata(intf, NULL);
 805                 goto error;
 806         }
 807
 808         /* let the user know what node this device is now attached to */
 809         dev_info(&intf->dev,
 810                  "Alphatrack Device #%d now attached to major %d minor %d\n",
 811                  (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR,
 812                  intf->minor);
 813
 814 exit:
 815         return retval;
 816
 817 error:
 818         usb_alphatrack_delete(dev);
 819
 820         return retval;
 821 }
 822
 823 /**
 824  *      usb_alphatrack_disconnect
 825  *
 826  *      Called by the usb core when the device is removed from the system.
 827  */
 828 static void usb_alphatrack_disconnect(struct usb_interface *intf)
 829 {
 830         struct usb_alphatrack *dev;
 831         int minor;
 832
 833         mutex_lock(&disconnect_mutex);
 834
 835         dev = usb_get_intfdata(intf);
 836         usb_set_intfdata(intf, NULL);
 837
 838         down(&dev->sem);
 839
 840         minor = intf->minor;
 841
 842         /* give back our minor */
 843         usb_deregister_dev(intf, &usb_alphatrack_class);
 844
 845         /* if the device is not opened, then we clean up right now */
 846         if (!dev->open_count) {
 847                 up(&dev->sem);
 848                 usb_alphatrack_delete(dev);
 849         } else {
 850                 dev->intf = NULL;
 851                 up(&dev->sem);
 852         }
 853
 854         atomic_set(&dev->writes_pending, 0);
 855         mutex_unlock(&disconnect_mutex);
 856
 857         dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
 858                  (minor - USB_ALPHATRACK_MINOR_BASE));
 859 }
 860
 861 /* usb specific object needed to register this driver with the usb subsystem */
 862 static struct usb_driver usb_alphatrack_driver = {
 863         .name = "alphatrack",
 864         .probe = usb_alphatrack_probe,
 865         .disconnect = usb_alphatrack_disconnect,
 866         .id_table = usb_alphatrack_table,
 867 };
 868
 869 /**
 870  *      usb_alphatrack_init
 871  */
 872 static int __init usb_alphatrack_init(void)
 873 {
 874         int retval;
 875
 876         /* register this driver with the USB subsystem */
 877         retval = usb_register(&usb_alphatrack_driver);
 878         if (retval)
 879                 err("usb_register failed for the " __FILE__
 880                     " driver. Error number %d\n", retval);
 881
 882         return retval;
 883 }
 884
 885 /**
 886  *      usb_alphatrack_exit
 887  */
 888 static void __exit usb_alphatrack_exit(void)
 889 {
 890         /* deregister this driver with the USB subsystem */
 891         usb_deregister(&usb_alphatrack_driver);
 892 }
 893
 894 module_init(usb_alphatrack_init);
 895 module_exit(usb_alphatrack_exit);