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 /*
  28  * Note: this currently uses a dumb ringbuffer for reads and writes.
  29  * A more optimal driver would cache and kill off outstanding urbs that are
  30  * now invalid, and ignore ones that already were in the queue but valid
  31  * as we only have 30 commands for the alphatrack. In particular this is
  32  * key for getting lights to flash in time as otherwise many commands
  33  * can be buffered up before the light change makes it to the interface.
  34  */
  35
  36 #include <linux/kernel.h>
  37 #include <linux/errno.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 const 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 /*
 104  * All interrupt in transfers are collected in a ring buffer to
 105  * avoid racing conditions and get better performance of the driver.
 106  */
 107
 108 static int ring_buffer_size = RING_BUFFER_SIZE;
 109
 110 module_param(ring_buffer_size, int, S_IRUGO);
 111 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
 112
 113 /* The write_buffer can one day contain more than one interrupt out transfer.*/
 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 mutex mtx;       /* 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 /** usb_alphatrack_delete */
 203 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
 204 {
 205         usb_alphatrack_abort_transfers(dev);
 206         usb_free_urb(dev->interrupt_in_urb);
 207         usb_free_urb(dev->interrupt_out_urb);
 208         kfree(dev->ring_buffer);
 209         kfree(dev->interrupt_in_buffer);
 210         kfree(dev->interrupt_out_buffer);
 211         kfree(dev->oldi_buffer);
 212         kfree(dev->write_buffer);
 213         kfree(dev);
 214 }
 215
 216 /** usb_alphatrack_interrupt_in_callback */
 217
 218 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
 219 {
 220         struct usb_alphatrack *dev = urb->context;
 221         unsigned int next_ring_head;
 222         int retval = -1;
 223
 224         if (urb->status) {
 225                 if (urb->status == -ENOENT ||
 226                     urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) {
 227                         goto exit;
 228                 } else {
 229                         dbg_info(&dev->intf->dev,
 230                                  "%s: nonzero status received: %d\n", __func__,
 231                                  urb->status);
 232                         goto resubmit;  /* maybe we can recover */
 233                 }
 234         }
 235
 236         if (urb->actual_length != INPUT_CMD_SIZE) {
 237                 dev_warn(&dev->intf->dev,
 238                          "Urb length was %d bytes!! Do something intelligent\n",
 239                          urb->actual_length);
 240         } else {
 241                 alphatrack_ocmd_info(&dev->intf->dev,
 242                                      &(*dev->ring_buffer)[dev->ring_tail].cmd,
 243                                      "%s", "bla");
 244                 if (memcmp
 245                     (dev->interrupt_in_buffer, dev->oldi_buffer,
 246                      INPUT_CMD_SIZE) == 0) {
 247                         goto resubmit;
 248                 }
 249                 memcpy(dev->oldi_buffer, dev->interrupt_in_buffer,
 250                        INPUT_CMD_SIZE);
 251
 252 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 253                 if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
 254                         goto resubmit;
 255                 if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
 256                         dev->offline = 2;
 257                         goto resubmit;
 258                 }
 259 /* Always pass one offline event up the stack */
 260                 if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
 261                         dev->offline = 0;
 262                 if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
 263                         dev->offline = 1;
 264 #endif
 265                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 266                          __func__, dev->ring_head, dev->ring_tail);
 267                 next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
 268
 269                 if (next_ring_head != dev->ring_tail) {
 270                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 271                                dev->interrupt_in_buffer, urb->actual_length);
 272                         dev->ring_head = next_ring_head;
 273                         retval = 0;
 274                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 275                 } else {
 276                         dev_warn(&dev->intf->dev,
 277                                  "Ring buffer overflow, %d bytes dropped\n",
 278                                  urb->actual_length);
 279                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 280                 }
 281         }
 282
 283 resubmit:
 284         /* resubmit if we're still running */
 285         if (dev->interrupt_in_running && dev->intf) {
 286                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 287                 if (retval)
 288                         dev_err(&dev->intf->dev,
 289                                 "usb_submit_urb failed (%d)\n", retval);
 290         }
 291
 292 exit:
 293         dev->interrupt_in_done = 1;
 294         wake_up_interruptible(&dev->read_wait);
 295 }
 296
 297 /** usb_alphatrack_interrupt_out_callback */
 298 static void usb_alphatrack_interrupt_out_callback(struct urb *urb)
 299 {
 300         struct usb_alphatrack *dev = urb->context;
 301
 302         /* sync/async unlink faults aren't errors */
 303         if (urb->status && !(urb->status == -ENOENT ||
 304                              urb->status == -ECONNRESET ||
 305                              urb->status == -ESHUTDOWN))
 306                 dbg_info(&dev->intf->dev,
 307                          "%s - nonzero write interrupt status received: %d\n",
 308                          __func__, urb->status);
 309         atomic_dec(&dev->writes_pending);
 310         dev->interrupt_out_busy = 0;
 311         wake_up_interruptible(&dev->write_wait);
 312 }
 313
 314 /** usb_alphatrack_open */
 315 static int usb_alphatrack_open(struct inode *inode, struct file *file)
 316 {
 317         struct usb_alphatrack *dev;
 318         int subminor;
 319         int retval = 0;
 320         struct usb_interface *interface;
 321
 322         nonseekable_open(inode, file);
 323         subminor = iminor(inode);
 324
 325         mutex_lock(&disconnect_mutex);
 326
 327         interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 328
 329         if (!interface) {
 330                 pr_err("%s - error, can't find device for minor %d\n",
 331                        __func__, subminor);
 332                 retval = -ENODEV;
 333                 goto unlock_disconnect_exit;
 334         }
 335
 336         dev = usb_get_intfdata(interface);
 337
 338         if (!dev) {
 339                 retval = -ENODEV;
 340                 goto unlock_disconnect_exit;
 341         }
 342
 343         /* lock this device */
 344         if (mutex_lock_interruptible(&dev->mtx)) {
 345                 retval = -ERESTARTSYS;
 346                 goto unlock_disconnect_exit;
 347         }
 348
 349         /* allow opening only once */
 350         if (dev->open_count) {
 351                 retval = -EBUSY;
 352                 goto unlock_exit;
 353         }
 354         dev->open_count = 1;
 355
 356         /* initialize in direction */
 357         dev->ring_head = 0;
 358         dev->ring_tail = 0;
 359         usb_fill_int_urb(dev->interrupt_in_urb,
 360                          interface_to_usbdev(interface),
 361                          usb_rcvintpipe(interface_to_usbdev(interface),
 362                                         dev->interrupt_in_endpoint->
 363                                         bEndpointAddress),
 364                          dev->interrupt_in_buffer,
 365                          dev->interrupt_in_endpoint_size,
 366                          usb_alphatrack_interrupt_in_callback, dev,
 367                          dev->interrupt_in_interval);
 368
 369         dev->interrupt_in_running = 1;
 370         dev->interrupt_in_done = 0;
 371         dev->enable = 1;
 372         dev->offline = 0;
 373
 374         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 375         if (retval) {
 376                 dev_err(&interface->dev,
 377                         "Couldn't submit interrupt_in_urb %d\n", retval);
 378                 dev->interrupt_in_running = 0;
 379                 dev->open_count = 0;
 380                 goto unlock_exit;
 381         }
 382
 383         /* save device in the file's private structure */
 384         file->private_data = dev;
 385
 386 unlock_exit:
 387         mutex_unlock(&dev->mtx);
 388
 389 unlock_disconnect_exit:
 390         mutex_unlock(&disconnect_mutex);
 391
 392         return retval;
 393 }
 394
 395 /** usb_alphatrack_release */
 396 static int usb_alphatrack_release(struct inode *inode, struct file *file)
 397 {
 398         struct usb_alphatrack *dev;
 399         int retval = 0;
 400
 401         dev = file->private_data;
 402
 403         if (dev == NULL) {
 404                 retval = -ENODEV;
 405                 goto exit;
 406         }
 407
 408         if (mutex_lock_interruptible(&dev->mtx)) {
 409                 retval = -ERESTARTSYS;
 410                 goto exit;
 411         }
 412
 413         if (dev->open_count != 1) {
 414                 retval = -ENODEV;
 415                 goto unlock_exit;
 416         }
 417
 418         if (dev->intf == NULL) {
 419                 /* the device was unplugged before the file was released */
 420                 mutex_unlock(&dev->mtx);
 421                 /* unlock here as usb_alphatrack_delete frees dev */
 422                 usb_alphatrack_delete(dev);
 423                 retval = -ENODEV;
 424                 goto exit;
 425         }
 426
 427         /* wait until write transfer is finished */
 428         if (dev->interrupt_out_busy)
 429                 wait_event_interruptible_timeout(dev->write_wait,
 430                                                  !dev->interrupt_out_busy,
 431                                                  2 * HZ);
 432         usb_alphatrack_abort_transfers(dev);
 433         dev->open_count = 0;
 434
 435 unlock_exit:
 436         mutex_unlock(&dev->mtx);
 437
 438 exit:
 439         return retval;
 440 }
 441
 442 /** usb_alphatrack_poll */
 443 static unsigned int usb_alphatrack_poll(struct file *file, poll_table *wait)
 444 {
 445         struct usb_alphatrack *dev;
 446         unsigned int mask = 0;
 447
 448         dev = file->private_data;
 449
 450         poll_wait(file, &dev->read_wait, wait);
 451         poll_wait(file, &dev->write_wait, wait);
 452
 453         if (dev->ring_head != dev->ring_tail)
 454                 mask |= POLLIN | POLLRDNORM;
 455         if (!dev->interrupt_out_busy)
 456                 mask |= POLLOUT | POLLWRNORM;
 457
 458         return mask;
 459 }
 460
 461 /** usb_alphatrack_read */
 462 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer,
 463                                    size_t count, loff_t *ppos)
 464 {
 465         struct usb_alphatrack *dev;
 466         int retval = 0;
 467
 468         int c = 0;
 469
 470         dev = file->private_data;
 471
 472         /* verify that we actually have some data to read */
 473         if (count == 0)
 474                 goto exit;
 475
 476         /* lock this object */
 477         if (mutex_lock_interruptible(&dev->mtx)) {
 478                 retval = -ERESTARTSYS;
 479                 goto exit;
 480         }
 481
 482         /* verify that the device wasn't unplugged */
 483         if (dev->intf == NULL) {
 484                 retval = -ENODEV;
 485                 pr_err("%s: No device or device unplugged %d\n",
 486                        __func__, retval);
 487                 goto unlock_exit;
 488         }
 489
 490         while (dev->ring_head == dev->ring_tail) {
 491                 if (file->f_flags & O_NONBLOCK) {
 492                         retval = -EAGAIN;
 493                         goto unlock_exit;
 494                 }
 495                 dev->interrupt_in_done = 0;
 496                 retval =
 497                     wait_event_interruptible(dev->read_wait,
 498                                              dev->interrupt_in_done);
 499                 if (retval < 0)
 500                         goto unlock_exit;
 501         }
 502
 503         alphatrack_ocmd_info(&dev->intf->dev,
 504                              &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s",
 505                              ": copying to userspace");
 506
 507         c = 0;
 508         while ((c < count) && (dev->ring_tail != dev->ring_head)) {
 509                 if (copy_to_user
 510                     (&buffer[c], &(*dev->ring_buffer)[dev->ring_tail],
 511                      INPUT_CMD_SIZE)) {
 512                         retval = -EFAULT;
 513                         goto unlock_exit;
 514                 }
 515                 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 516                 c += INPUT_CMD_SIZE;
 517                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 518                          __func__, dev->ring_head, dev->ring_tail);
 519         }
 520         retval = c;
 521
 522 unlock_exit:
 523         /* unlock the device */
 524         mutex_unlock(&dev->mtx);
 525
 526 exit:
 527         return retval;
 528 }
 529
 530 /** usb_alphatrack_write */
 531 static ssize_t usb_alphatrack_write(struct file *file,
 532                                     const char __user *buffer, size_t count,
 533                                     loff_t *ppos)
 534 {
 535         struct usb_alphatrack *dev;
 536         size_t bytes_to_write;
 537         int retval = 0;
 538
 539         dev = file->private_data;
 540
 541         /* verify that we actually have some data to write */
 542         if (count == 0)
 543                 goto exit;
 544
 545         /* lock this object */
 546         if (mutex_lock_interruptible(&dev->mtx)) {
 547                 retval = -ERESTARTSYS;
 548                 goto exit;
 549         }
 550
 551         /* verify that the device wasn't unplugged */
 552         if (dev->intf == NULL) {
 553                 retval = -ENODEV;
 554                 pr_err("%s: No device or device unplugged %d\n",
 555                        __func__, retval);
 556                 goto unlock_exit;
 557         }
 558
 559         /* wait until previous transfer is finished */
 560         if (dev->interrupt_out_busy) {
 561                 if (file->f_flags & O_NONBLOCK) {
 562                         retval = -EAGAIN;
 563                         goto unlock_exit;
 564                 }
 565                 retval =
 566                     wait_event_interruptible(dev->write_wait,
 567                                              !dev->interrupt_out_busy);
 568                 if (retval < 0)
 569                         goto unlock_exit;
 570         }
 571
 572         /* write the data into interrupt_out_buffer from userspace */
 573         /* FIXME - if you write more than 12 bytes this breaks */
 574         bytes_to_write =
 575             min(count, write_buffer_size * dev->interrupt_out_endpoint_size);
 576         if (bytes_to_write < count)
 577                 dev_warn(&dev->intf->dev,
 578                          "Write buffer overflow, %zd bytes dropped\n",
 579                          count - bytes_to_write);
 580
 581         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 582                  __func__, count, bytes_to_write);
 583
 584         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 585                 retval = -EFAULT;
 586                 goto unlock_exit;
 587         }
 588
 589         if (dev->interrupt_out_endpoint == NULL) {
 590                 dev_err(&dev->intf->dev, "Endpoint should not be null!\n");
 591                 goto unlock_exit;
 592         }
 593
 594         /* send off the urb */
 595         usb_fill_int_urb(dev->interrupt_out_urb,
 596                          interface_to_usbdev(dev->intf),
 597                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 598                                         dev->interrupt_out_endpoint->
 599                                         bEndpointAddress),
 600                          dev->interrupt_out_buffer, bytes_to_write,
 601                          usb_alphatrack_interrupt_out_callback, dev,
 602                          dev->interrupt_out_interval);
 603         dev->interrupt_out_busy = 1;
 604         atomic_inc(&dev->writes_pending);
 605         wmb();
 606
 607         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 608         if (retval) {
 609                 dev->interrupt_out_busy = 0;
 610                 dev_err(&dev->intf->dev,
 611                         "Couldn't submit interrupt_out_urb %d\n", retval);
 612                 atomic_dec(&dev->writes_pending);
 613                 goto unlock_exit;
 614         }
 615         retval = bytes_to_write;
 616
 617 unlock_exit:
 618         /* unlock the device */
 619         mutex_unlock(&dev->mtx);
 620
 621 exit:
 622         return retval;
 623 }
 624
 625 /* file operations needed when we register this driver */
 626 static const struct file_operations usb_alphatrack_fops = {
 627         .owner = THIS_MODULE,
 628         .read = usb_alphatrack_read,
 629         .write = usb_alphatrack_write,
 630         .open = usb_alphatrack_open,
 631         .release = usb_alphatrack_release,
 632         .poll = usb_alphatrack_poll,
 633         .llseek = no_llseek,
 634 };
 635
 636 /*
 637  * usb class driver info in order to get a minor number from the usb core,
 638  * and to have the device registered with the driver core
 639  */
 640
 641 static struct usb_class_driver usb_alphatrack_class = {
 642         .name = "alphatrack%d",
 643         .fops = &usb_alphatrack_fops,
 644         .minor_base = USB_ALPHATRACK_MINOR_BASE,
 645 };
 646
 647 /**
 648  *      usb_alphatrack_probe
 649  *
 650  *      Called by the usb core when a new device is connected that it thinks
 651  *      this driver might be interested in.
 652  */
 653 static int usb_alphatrack_probe(struct usb_interface *intf,
 654                                 const struct usb_device_id *id)
 655 {
 656         struct usb_device *udev = interface_to_usbdev(intf);
 657         struct usb_alphatrack *dev = NULL;
 658         struct usb_host_interface *iface_desc;
 659         struct usb_endpoint_descriptor *endpoint;
 660         int i;
 661         int true_size;
 662         int retval = -ENOMEM;
 663
 664         /* allocate memory for our device state and initialize it */
 665
 666         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 667         if (dev == NULL)
 668                 goto exit;
 669
 670         mutex_init(&dev->mtx);
 671         dev->intf = intf;
 672         init_waitqueue_head(&dev->read_wait);
 673         init_waitqueue_head(&dev->write_wait);
 674
 675         iface_desc = intf->cur_altsetting;
 676
 677         /* set up the endpoint information */
 678         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 679                 endpoint = &iface_desc->endpoint[i].desc;
 680
 681                 if (usb_endpoint_is_int_in(endpoint))
 682                         dev->interrupt_in_endpoint = endpoint;
 683
 684                 if (usb_endpoint_is_int_out(endpoint))
 685                         dev->interrupt_out_endpoint = endpoint;
 686         }
 687         if (dev->interrupt_in_endpoint == NULL) {
 688                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 689                 goto error;
 690         }
 691         if (dev->interrupt_out_endpoint == NULL)
 692                 dev_warn(&intf->dev,
 693                          "Interrupt out endpoint not found (using control endpoint instead)\n");
 694
 695         dev->interrupt_in_endpoint_size =
 696             le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 697
 698         if (dev->interrupt_in_endpoint_size != 64)
 699                 dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
 700
 701         if (ring_buffer_size == 0)
 702                 ring_buffer_size = RING_BUFFER_SIZE;
 703
 704         true_size = min(ring_buffer_size, RING_BUFFER_SIZE);
 705
 706         /*
 707          * FIXME - there are more usb_alloc routines for dma correctness.
 708          * Needed?
 709          */
 710         dev->ring_buffer = kmalloc_array(true_size,
 711                                          sizeof(struct alphatrack_icmd),
 712                                          GFP_KERNEL);
 713         if (!dev->ring_buffer)
 714                 goto error;
 715
 716         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size,
 717                                            GFP_KERNEL);
 718         if (!dev->interrupt_in_buffer)
 719                 goto error;
 720
 721         dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 722         if (!dev->oldi_buffer)
 723                 goto error;
 724
 725         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 726         if (!dev->interrupt_in_urb) {
 727                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 728                 goto error;
 729         }
 730
 731         dev->interrupt_out_endpoint_size =
 732             dev->interrupt_out_endpoint ? le16_to_cpu(dev->
 733                                                       interrupt_out_endpoint->
 734                                                       wMaxPacketSize) : udev->
 735             descriptor.bMaxPacketSize0;
 736
 737         if (dev->interrupt_out_endpoint_size != 64)
 738                 dev_warn(&intf->dev,
 739                          "Interrupt out endpoint size is not 64!)\n");
 740
 741         if (write_buffer_size == 0)
 742                 write_buffer_size = WRITE_BUFFER_SIZE;
 743         true_size = min(write_buffer_size, WRITE_BUFFER_SIZE);
 744
 745         dev->interrupt_out_buffer =
 746                 kmalloc_array(true_size,
 747                               dev->interrupt_out_endpoint_size,
 748                               GFP_KERNEL);
 749         if (!dev->interrupt_out_buffer)
 750                 goto error;
 751
 752         dev->write_buffer = kmalloc_array(true_size,
 753                                           sizeof(struct alphatrack_ocmd),
 754                                           GFP_KERNEL);
 755         if (!dev->write_buffer)
 756                 goto error;
 757
 758         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 759         if (!dev->interrupt_out_urb) {
 760                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 761                 goto error;
 762         }
 763         dev->interrupt_in_interval =
 764             min_interrupt_in_interval >
 765             dev->interrupt_in_endpoint->
 766             bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->
 767             bInterval;
 768         if (dev->interrupt_out_endpoint)
 769                 dev->interrupt_out_interval =
 770                     min_interrupt_out_interval >
 771                     dev->interrupt_out_endpoint->
 772                     bInterval ? min_interrupt_out_interval : dev->
 773                     interrupt_out_endpoint->bInterval;
 774
 775         /* we can register the device now, as it is ready */
 776         usb_set_intfdata(intf, dev);
 777
 778         atomic_set(&dev->writes_pending, 0);
 779         retval = usb_register_dev(intf, &usb_alphatrack_class);
 780         if (retval) {
 781                 /* something prevented us from registering this driver */
 782                 dev_err(&intf->dev,
 783                         "Not able to get a minor for this device.\n");
 784                 usb_set_intfdata(intf, NULL);
 785                 goto error;
 786         }
 787
 788         /* let the user know what node this device is now attached to */
 789         dev_info(&intf->dev,
 790                  "Alphatrack Device #%d now attached to major %d minor %d\n",
 791                  (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR,
 792                  intf->minor);
 793
 794 exit:
 795         return retval;
 796
 797 error:
 798         usb_alphatrack_delete(dev);
 799
 800         return retval;
 801 }
 802
 803 /**
 804  *      usb_alphatrack_disconnect
 805  *
 806  *      Called by the usb core when the device is removed from the system.
 807  */
 808 static void usb_alphatrack_disconnect(struct usb_interface *intf)
 809 {
 810         struct usb_alphatrack *dev;
 811         int minor;
 812
 813         mutex_lock(&disconnect_mutex);
 814
 815         dev = usb_get_intfdata(intf);
 816         usb_set_intfdata(intf, NULL);
 817
 818         mutex_lock(&dev->mtx);
 819
 820         minor = intf->minor;
 821
 822         /* give back our minor */
 823         usb_deregister_dev(intf, &usb_alphatrack_class);
 824
 825         /* if the device is not opened, then we clean up right now */
 826         if (!dev->open_count) {
 827                 mutex_unlock(&dev->mtx);
 828                 usb_alphatrack_delete(dev);
 829         } else {
 830                 atomic_set(&dev->writes_pending, 0);
 831                 dev->intf = NULL;
 832                 mutex_unlock(&dev->mtx);
 833         }
 834
 835         mutex_unlock(&disconnect_mutex);
 836
 837         dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
 838                  (minor - USB_ALPHATRACK_MINOR_BASE));
 839 }
 840
 841 /* usb specific object needed to register this driver with the usb subsystem */
 842 static struct usb_driver usb_alphatrack_driver = {
 843         .name = "alphatrack",
 844         .probe = usb_alphatrack_probe,
 845         .disconnect = usb_alphatrack_disconnect,
 846         .id_table = usb_alphatrack_table,
 847 };
 848
 849 module_usb_driver(usb_alphatrack_driver);