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 #include <linux/version.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <linux/input.h>
  46 #include <linux/usb.h>
  47 #include <linux/poll.h>
  48
  49 #include "surface_sysfs.h"
  50
  51 /* make this work on older kernel versions */
  52
  53 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19)
  54 #include "frontier_compat.h"
  55 #endif /* older kernel versions */
  56
  57 #include "alphatrack.h"
  58
  59 #define VENDOR_ID       0x165b
  60 #define PRODUCT_ID      0xfad1
  61
  62 #ifdef CONFIG_USB_DYNAMIC_MINORS
  63 #define USB_ALPHATRACK_MINOR_BASE       0
  64 #else
  65 // FIXME 176 - is another driver's minor - apply for that
  66 // #define USB_ALPHATRACK_MINOR_BASE    177
  67 #define USB_ALPHATRACK_MINOR_BASE       176
  68 #endif
  69
  70 /* table of devices that work with this driver */
  71 static struct usb_device_id usb_alphatrack_table [] = {
  72         { USB_DEVICE(VENDOR_ID, PRODUCT_ID) },
  73         { }                                     /* Terminating entry */
  74 };
  75
  76 MODULE_DEVICE_TABLE(usb, usb_alphatrack_table);
  77 MODULE_VERSION("0.40");
  78 MODULE_AUTHOR("Mike Taht <m@taht.net>");
  79 MODULE_DESCRIPTION("Alphatrack USB Driver");
  80 MODULE_LICENSE("GPL");
  81 MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface");
  82
  83 /* These aren't done yet */
  84
  85 #define SUPPRESS_EXTRA_ONLINE_EVENTS 0
  86 #define BUFFERED_WRITES 0
  87 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0
  88 #define COMPRESS_FADER_EVENTS 0
  89
  90 #define BUFFERED_READS 1
  91 #define RING_BUFFER_SIZE 512
  92 #define WRITE_BUFFER_SIZE 34
  93 #define ALPHATRACK_USB_TIMEOUT 10
  94 #define OUTPUT_CMD_SIZE 8
  95 #define INPUT_CMD_SIZE 12
  96
  97
  98 static int debug = 0;
  99
 100 /* Use our own dbg macro */
 101 #define dbg_info(dev, format, arg...) do { if (debug) dev_info(dev , format , ## arg); } while (0)
 102
 103 #define alphatrack_ocmd_info(dev, cmd, format, arg...)
 104
 105 #define alphatrack_icmd_info(dev, cmd, format, arg...)
 106
 107
 108 /* Module parameters */
 109
 110 module_param(debug, int, S_IRUGO | S_IWUSR);
 111 MODULE_PARM_DESC(debug, "Debug enabled or not");
 112
 113 /* All interrupt in transfers are collected in a ring buffer to
 114  * avoid racing conditions and get better performance of the driver.
 115  */
 116
 117 static int ring_buffer_size = RING_BUFFER_SIZE;
 118
 119 module_param(ring_buffer_size, int,  S_IRUGO);
 120 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
 121
 122 /* The write_buffer can one day contain more than one interrupt out transfer.
 123  */
 124
 125 static int write_buffer_size = WRITE_BUFFER_SIZE;
 126 module_param(write_buffer_size, int,  S_IRUGO);
 127 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 128
 129 /*
 130  * Increase the interval for debugging purposes.
 131  * or set to 1 to use the standard interval from the endpoint descriptors.
 132  */
 133
 134 static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT;
 135 module_param(min_interrupt_in_interval, int, 0);
 136 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 137
 138 static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT;
 139 module_param(min_interrupt_out_interval, int, 0);
 140 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 141
 142
 143
 144 /* Structure to hold all of our device specific stuff */
 145
 146 struct usb_alphatrack {
 147         struct semaphore        sem;            /* locks this structure */
 148         struct usb_interface*   intf;           /* save off the usb interface pointer */
 149         int                     open_count;     /* number of times this port has been opened */
 150
 151         struct alphatrack_icmd  (*ring_buffer)[RING_BUFFER_SIZE]; /* just make c happy */
 152         struct alphatrack_ocmd  (*write_buffer)[WRITE_BUFFER_SIZE]; /* just make c happy */
 153         unsigned int            ring_head;
 154         unsigned int            ring_tail;
 155
 156         wait_queue_head_t       read_wait;
 157         wait_queue_head_t       write_wait;
 158
 159         unsigned char*          interrupt_in_buffer;
 160         unsigned char*          oldi_buffer;
 161         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 162         struct urb*             interrupt_in_urb;
 163         int                     interrupt_in_interval;
 164         size_t                  interrupt_in_endpoint_size;
 165         int                     interrupt_in_running;
 166         int                     interrupt_in_done;
 167
 168         char*                   interrupt_out_buffer;
 169         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 170         struct urb*             interrupt_out_urb;
 171         int                     interrupt_out_interval;
 172         size_t                  interrupt_out_endpoint_size;
 173         int                     interrupt_out_busy;
 174
 175         atomic_t writes_pending;
 176         int event; /* alternate interface to events */
 177         int fader; /* 10 bits */
 178         int lights; /* 23 bits */
 179         unsigned char dump_state; /* 0 if disabled 1 if enabled */
 180         unsigned char enable; /* 0 if disabled 1 if enabled */
 181         unsigned char offline; /* if the device is out of range or asleep */
 182         unsigned char verbose; /* be verbose in error reporting */
 183         unsigned char  last_cmd[OUTPUT_CMD_SIZE];
 184         unsigned char  screen[32];
 185 };
 186
 187 /* prevent races between open() and disconnect() */
 188 static DEFINE_MUTEX(disconnect_mutex);
 189
 190 /* forward declaration */
 191
 192 static struct usb_driver usb_alphatrack_driver;
 193
 194 /**
 195  *      usb_alphatrack_abort_transfers
 196  *      aborts transfers and frees associated data structures
 197  */
 198 static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev)
 199 {
 200         /* shutdown transfer */
 201         if (dev->interrupt_in_running) {
 202                 dev->interrupt_in_running = 0;
 203                 if (dev->intf)
 204                         usb_kill_urb(dev->interrupt_in_urb);
 205         }
 206         if (dev->interrupt_out_busy)
 207                 if (dev->intf)
 208                         usb_kill_urb(dev->interrupt_out_urb);
 209 }
 210
 211 /**
 212  *      usb_alphatrack_delete
 213  */
 214 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
 215 {
 216         usb_alphatrack_abort_transfers(dev);
 217         usb_free_urb(dev->interrupt_in_urb);
 218         usb_free_urb(dev->interrupt_out_urb);
 219         kfree(dev->ring_buffer);
 220         kfree(dev->interrupt_in_buffer);
 221         kfree(dev->interrupt_out_buffer);
 222         kfree(dev); // fixme oldi_buffer
 223 }
 224
 225 /**
 226  *      usb_alphatrack_interrupt_in_callback
 227  */
 228
 229 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
 230 {
 231         struct usb_alphatrack *dev = urb->context;
 232         unsigned int next_ring_head;
 233         int retval = -1;
 234
 235         if (urb->status) {
 236                 if (urb->status == -ENOENT ||
 237                     urb->status == -ECONNRESET ||
 238                     urb->status == -ESHUTDOWN) {
 239                         goto exit;
 240                 } else {
 241                         dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
 242                                  __FUNCTION__, urb->status);
 243                         goto resubmit; /* maybe we can recover */
 244                 }
 245         }
 246
 247         if (urb->actual_length != INPUT_CMD_SIZE) {
 248                 dev_warn(&dev->intf->dev,
 249                          "Urb length was %d bytes!! Do something intelligent \n", urb->actual_length);
 250         } else {
 251                  alphatrack_ocmd_info(&dev->intf->dev,&(*dev->ring_buffer)[dev->ring_tail].cmd,"%s", "bla");
 252                  if(memcmp(dev->interrupt_in_buffer,dev->oldi_buffer,INPUT_CMD_SIZE)==0) {
 253                                                 goto resubmit;
 254                 }
 255                 memcpy(dev->oldi_buffer,dev->interrupt_in_buffer,INPUT_CMD_SIZE);
 256
 257 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 258         if(dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff) { goto resubmit; }
 259                 if(dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) { dev->offline = 2; goto resubmit; }
 260 /* Always pass one offline event up the stack */
 261                 if(dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff) { dev->offline = 0; }
 262                 if(dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff) { dev->offline = 1; }
 263 #endif
 264                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __FUNCTION__,dev->ring_head,dev->ring_tail);
 265                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 266
 267                 if (next_ring_head != dev->ring_tail) {
 268                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 269                                                  dev->interrupt_in_buffer, urb->actual_length);
 270                         dev->ring_head = next_ring_head;
 271                         retval = 0;
 272                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 273                 } else {
 274                         dev_warn(&dev->intf->dev,
 275                                  "Ring buffer overflow, %d bytes dropped\n",
 276                                  urb->actual_length);
 277                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 278                 }
 279         }
 280
 281 resubmit:
 282         /* resubmit if we're still running */
 283         if (dev->interrupt_in_running && dev->intf) {
 284                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 285                 if (retval)
 286                         dev_err(&dev->intf->dev,
 287                                 "usb_submit_urb failed (%d)\n", retval);
 288         }
 289
 290 exit:
 291         dev->interrupt_in_done = 1;
 292         wake_up_interruptible(&dev->read_wait);
 293 }
 294
 295 /**
 296  *      usb_alphatrack_interrupt_out_callback
 297  */
 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                          __FUNCTION__, urb->status);
 309         atomic_dec(&dev->writes_pending);
 310         dev->interrupt_out_busy = 0;
 311         wake_up_interruptible(&dev->write_wait);
 312 }
 313
 314 /**
 315  *      usb_alphatrack_open
 316  */
 317 static int usb_alphatrack_open(struct inode *inode, struct file *file)
 318 {
 319         struct usb_alphatrack *dev;
 320         int subminor;
 321         int retval = 0;
 322         struct usb_interface *interface;
 323
 324         nonseekable_open(inode, file);
 325         subminor = iminor(inode);
 326
 327         mutex_lock(&disconnect_mutex);
 328
 329         interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 330
 331         if (!interface) {
 332                 err("%s - error, can't find device for minor %d\n",
 333                      __FUNCTION__, subminor);
 334                 retval = -ENODEV;
 335                 goto unlock_disconnect_exit;
 336         }
 337
 338         dev = usb_get_intfdata(interface);
 339
 340         if (!dev) {
 341                 retval = -ENODEV;
 342                 goto unlock_disconnect_exit;
 343         }
 344
 345         /* lock this device */
 346         if (down_interruptible(&dev->sem)) {
 347                 retval = -ERESTARTSYS;
 348                 goto unlock_disconnect_exit;
 349         }
 350
 351         /* allow opening only once */
 352         if (dev->open_count) {
 353                 retval = -EBUSY;
 354                 goto unlock_exit;
 355         }
 356         dev->open_count = 1;
 357
 358         /* initialize in direction */
 359         dev->ring_head = 0;
 360         dev->ring_tail = 0;
 361         usb_fill_int_urb(dev->interrupt_in_urb,
 362                          interface_to_usbdev(interface),
 363                          usb_rcvintpipe(interface_to_usbdev(interface),
 364                                         dev->interrupt_in_endpoint->bEndpointAddress),
 365                          dev->interrupt_in_buffer,
 366                          dev->interrupt_in_endpoint_size,
 367                          usb_alphatrack_interrupt_in_callback,
 368                          dev,
 369                          dev->interrupt_in_interval);
 370
 371         dev->interrupt_in_running = 1;
 372         dev->interrupt_in_done = 0;
 373         dev->enable = 1;
 374         dev->offline = 0;
 375
 376         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 377         if (retval) {
 378                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 379                 dev->interrupt_in_running = 0;
 380                 dev->open_count = 0;
 381                 goto unlock_exit;
 382         }
 383
 384         /* save device in the file's private structure */
 385         file->private_data = dev;
 386
 387
 388 unlock_exit:
 389         up(&dev->sem);
 390
 391 unlock_disconnect_exit:
 392         mutex_unlock(&disconnect_mutex);
 393
 394         return retval;
 395 }
 396
 397 /**
 398  *      usb_alphatrack_release
 399  */
 400 static int usb_alphatrack_release(struct inode *inode, struct file *file)
 401 {
 402         struct usb_alphatrack *dev;
 403         int retval = 0;
 404
 405         dev = file->private_data;
 406
 407         if (dev == NULL) {
 408                 retval = -ENODEV;
 409                 goto exit;
 410         }
 411
 412         if (down_interruptible(&dev->sem)) {
 413                 retval = -ERESTARTSYS;
 414                 goto exit;
 415         }
 416
 417         if (dev->open_count != 1) {
 418                 retval = -ENODEV;
 419                 goto unlock_exit;
 420         }
 421
 422         if (dev->intf == NULL) {
 423                 /* the device was unplugged before the file was released */
 424                 up(&dev->sem);
 425                 /* unlock here as usb_alphatrack_delete frees dev */
 426                 usb_alphatrack_delete(dev);
 427                 retval = -ENODEV;
 428                 goto exit;
 429         }
 430
 431         /* wait until write transfer is finished */
 432         if (dev->interrupt_out_busy)
 433                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 434         usb_alphatrack_abort_transfers(dev);
 435         dev->open_count = 0;
 436
 437 unlock_exit:
 438         up(&dev->sem);
 439
 440 exit:
 441         return retval;
 442 }
 443
 444 /**
 445  *      usb_alphatrack_poll
 446  */
 447 static unsigned int usb_alphatrack_poll(struct file *file, poll_table *wait)
 448 {
 449         struct usb_alphatrack *dev;
 450         unsigned int mask = 0;
 451
 452         dev = file->private_data;
 453
 454         poll_wait(file, &dev->read_wait, wait);
 455         poll_wait(file, &dev->write_wait, wait);
 456
 457         if (dev->ring_head != dev->ring_tail)
 458                 mask |= POLLIN | POLLRDNORM;
 459         if (!dev->interrupt_out_busy)
 460                 mask |= POLLOUT | POLLWRNORM;
 461
 462         return mask;
 463 }
 464
 465 /**
 466  *      usb_alphatrack_read
 467  */
 468 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer, size_t count,
 469                            loff_t *ppos)
 470 {
 471         struct usb_alphatrack *dev;
 472         int retval = 0;
 473
 474         int c = 0;
 475
 476         dev = file->private_data;
 477
 478         /* verify that we actually have some data to read */
 479         if (count == 0)
 480                 goto exit;
 481
 482         /* lock this object */
 483         if (down_interruptible(&dev->sem)) {
 484                 retval = -ERESTARTSYS;
 485                 goto exit;
 486         }
 487
 488         /* verify that the device wasn't unplugged */
 489         if (dev->intf == NULL) {
 490                 retval = -ENODEV;
 491                 err("No device or device unplugged %d\n", retval);
 492                 goto unlock_exit;
 493         }
 494
 495         while (dev->ring_head == dev->ring_tail) {
 496                                         if (file->f_flags & O_NONBLOCK) {
 497                                                                         retval = -EAGAIN;
 498                                                                         goto unlock_exit;
 499                                         }
 500                                         dev->interrupt_in_done = 0 ;
 501                                         retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 502                                         if (retval < 0) {
 503                                                                         goto unlock_exit;
 504                                         }
 505         }
 506
 507         alphatrack_ocmd_info(&dev->intf->dev, &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s", ": copying to userspace");
 508
 509            c = 0;
 510            while((c < count) && (dev->ring_tail != dev->ring_head)) {
 511                                                  if (copy_to_user(&buffer[c], &(*dev->ring_buffer)[dev->ring_tail], 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", __FUNCTION__,dev->ring_head,dev->ring_tail);
 518            }
 519            retval = c;
 520
 521 unlock_exit:
 522         /* unlock the device */
 523         up(&dev->sem);
 524
 525 exit:
 526         return retval;
 527 }
 528
 529 /**
 530  *      usb_alphatrack_write
 531  */
 532 static ssize_t usb_alphatrack_write(struct file *file, const char __user *buffer,
 533                             size_t count, 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 (down_interruptible(&dev->sem)) {
 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                 err("No device or device unplugged %d\n", retval);
 555                 goto unlock_exit;
 556         }
 557
 558         /* wait until previous transfer is finished */
 559         if (dev->interrupt_out_busy) {
 560                 if (file->f_flags & O_NONBLOCK) {
 561                         retval = -EAGAIN;
 562                         goto unlock_exit;
 563                 }
 564                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 565                 if (retval < 0) {
 566                         goto unlock_exit;
 567                 }
 568         }
 569
 570         /* write the data into interrupt_out_buffer from userspace */
 571   /* FIXME - if you write more than 12 bytes this breaks */
 572         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 573         if (bytes_to_write < count)
 574                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
 575
 576         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n", __FUNCTION__, count, bytes_to_write);
 577
 578         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 579                 retval = -EFAULT;
 580                 goto unlock_exit;
 581         }
 582
 583         if (dev->interrupt_out_endpoint == NULL) {
 584                 err("Endpoint should not be be null! \n");
 585                 goto unlock_exit;
 586         }
 587
 588         /* send off the urb */
 589         usb_fill_int_urb(dev->interrupt_out_urb,
 590                          interface_to_usbdev(dev->intf),
 591                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 592                                         dev->interrupt_out_endpoint->bEndpointAddress),
 593                          dev->interrupt_out_buffer,
 594                          bytes_to_write,
 595                          usb_alphatrack_interrupt_out_callback,
 596                          dev,
 597                          dev->interrupt_out_interval);
 598         dev->interrupt_out_busy = 1;
 599         atomic_inc(&dev->writes_pending);
 600         wmb();
 601
 602         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 603         if (retval) {
 604                 dev->interrupt_out_busy = 0;
 605                 err("Couldn't submit interrupt_out_urb %d\n", retval);
 606                 atomic_dec(&dev->writes_pending);
 607                 goto unlock_exit;
 608         }
 609         retval = bytes_to_write;
 610
 611 unlock_exit:
 612         /* unlock the device */
 613         up(&dev->sem);
 614
 615 exit:
 616         return retval;
 617 }
 618
 619 /* file operations needed when we register this driver */
 620 static const struct file_operations usb_alphatrack_fops = {
 621         .owner =        THIS_MODULE,
 622         .read  =        usb_alphatrack_read,
 623         .write =        usb_alphatrack_write,
 624         .open =         usb_alphatrack_open,
 625         .release =      usb_alphatrack_release,
 626         .poll =         usb_alphatrack_poll,
 627 };
 628
 629 /*
 630  * usb class driver info in order to get a minor number from the usb core,
 631  * and to have the device registered with the driver core
 632  */
 633
 634 static struct usb_class_driver usb_alphatrack_class = {
 635         .name =         "alphatrack%d",
 636         .fops =         &usb_alphatrack_fops,
 637         .minor_base =   USB_ALPHATRACK_MINOR_BASE,
 638 };
 639
 640
 641 /**
 642  *      usb_alphatrack_probe
 643  *
 644  *      Called by the usb core when a new device is connected that it thinks
 645  *      this driver might be interested in.
 646  */
 647 static int usb_alphatrack_probe(struct usb_interface *intf, const struct usb_device_id *id)
 648 {
 649         struct usb_device *udev = interface_to_usbdev(intf);
 650         struct usb_alphatrack *dev = NULL;
 651         struct usb_host_interface *iface_desc;
 652         struct usb_endpoint_descriptor *endpoint;
 653         int i;
 654         int true_size;
 655         int retval = -ENOMEM;
 656
 657         /* allocate memory for our device state and intialize it */
 658
 659         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 660         if (dev == NULL) {
 661                 dev_err(&intf->dev, "Out of memory\n");
 662                 goto exit;
 663         }
 664         init_MUTEX(&dev->sem);
 665         dev->intf = intf;
 666         init_waitqueue_head(&dev->read_wait);
 667         init_waitqueue_head(&dev->write_wait);
 668
 669         iface_desc = intf->cur_altsetting;
 670
 671         /* set up the endpoint information */
 672         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 673                 endpoint = &iface_desc->endpoint[i].desc;
 674
 675                 if (usb_endpoint_is_int_in(endpoint))
 676                         dev->interrupt_in_endpoint = endpoint;
 677
 678                 if (usb_endpoint_is_int_out(endpoint))
 679                         dev->interrupt_out_endpoint = endpoint;
 680         }
 681         if (dev->interrupt_in_endpoint == NULL) {
 682                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 683                 goto error;
 684         }
 685         if (dev->interrupt_out_endpoint == NULL)
 686                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 687
 688         dev->interrupt_in_endpoint_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 689
 690         if (dev->interrupt_in_endpoint_size != 64)
 691             dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
 692
 693         if(ring_buffer_size == 0) { ring_buffer_size = RING_BUFFER_SIZE; }
 694
 695         true_size = min(ring_buffer_size,RING_BUFFER_SIZE);
 696
 697         /* FIXME - there are more usb_alloc routines for dma correctness. Needed? */
 698
 699 //      dev->ring_buffer = kmalloc((true_size*sizeof(struct alphatrack_icmd))+12, GFP_KERNEL);
 700         dev->ring_buffer = kmalloc((true_size*sizeof(struct alphatrack_icmd)), GFP_KERNEL);
 701
 702         if (!dev->ring_buffer) {
 703                 dev_err(&intf->dev, "Couldn't allocate input ring_buffer of size %d\n",true_size);
 704                 goto error;
 705         }
 706
 707         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 708
 709         if (!dev->interrupt_in_buffer) {
 710                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 711                 goto error;
 712         }
 713         dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 714         if (!dev->oldi_buffer) {
 715                 dev_err(&intf->dev, "Couldn't allocate old buffer\n");
 716                 goto error;
 717         }
 718         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 719         if (!dev->interrupt_in_urb) {
 720                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 721                 goto error;
 722         }
 723
 724         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize) :
 725                                                                          udev->descriptor.bMaxPacketSize0;
 726
 727         if (dev->interrupt_out_endpoint_size !=64)
 728                 dev_warn(&intf->dev, "Interrupt out endpoint size is not 64!)\n");
 729
 730         if(write_buffer_size == 0) { write_buffer_size = WRITE_BUFFER_SIZE; }
 731         true_size = min(write_buffer_size,WRITE_BUFFER_SIZE);
 732
 733         dev->interrupt_out_buffer = kmalloc(true_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 734
 735         if (!dev->interrupt_out_buffer) {
 736                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 737                 goto error;
 738         }
 739
 740         dev->write_buffer = kmalloc(sizeof(struct alphatrack_ocmd)*true_size, GFP_KERNEL);
 741
 742         if (!dev->write_buffer) {
 743                 dev_err(&intf->dev, "Couldn't allocate write_buffer \n");
 744                 goto error;
 745         }
 746
 747         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 748         if (!dev->interrupt_out_urb) {
 749                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 750                 goto error;
 751         }
 752         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 753         if (dev->interrupt_out_endpoint)
 754                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 755
 756         /* we can register the device now, as it is ready */
 757         usb_set_intfdata(intf, dev);
 758
 759         atomic_set(&dev->writes_pending,0);
 760         retval = usb_register_dev(intf, &usb_alphatrack_class);
 761         if (retval) {
 762                 /* something prevented us from registering this driver */
 763                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 764                 usb_set_intfdata(intf, NULL);
 765                 goto error;
 766         }
 767
 768         /* let the user know what node this device is now attached to */
 769         dev_info(&intf->dev, "Alphatrack Device #%d now attached to major %d minor %d\n",
 770                 (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR, intf->minor);
 771
 772 exit:
 773         return retval;
 774
 775 error:
 776         usb_alphatrack_delete(dev);
 777
 778         return retval;
 779 }
 780
 781 /**
 782  *      usb_alphatrack_disconnect
 783  *
 784  *      Called by the usb core when the device is removed from the system.
 785  */
 786 static void usb_alphatrack_disconnect(struct usb_interface *intf)
 787 {
 788         struct usb_alphatrack *dev;
 789         int minor;
 790
 791         mutex_lock(&disconnect_mutex);
 792
 793         dev = usb_get_intfdata(intf);
 794         usb_set_intfdata(intf, NULL);
 795
 796         down(&dev->sem);
 797
 798         minor = intf->minor;
 799
 800         /* give back our minor */
 801         usb_deregister_dev(intf, &usb_alphatrack_class);
 802
 803         /* if the device is not opened, then we clean up right now */
 804         if (!dev->open_count) {
 805                 up(&dev->sem);
 806                 usb_alphatrack_delete(dev);
 807         } else {
 808                 dev->intf = NULL;
 809                 up(&dev->sem);
 810         }
 811
 812         atomic_set(&dev->writes_pending,0);
 813         mutex_unlock(&disconnect_mutex);
 814
 815         dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
 816                  (minor - USB_ALPHATRACK_MINOR_BASE));
 817 }
 818
 819 /* usb specific object needed to register this driver with the usb subsystem */
 820 static struct usb_driver usb_alphatrack_driver = {
 821         .name =         "alphatrack",
 822         .probe =        usb_alphatrack_probe,
 823         .disconnect =   usb_alphatrack_disconnect,
 824         .id_table =     usb_alphatrack_table,
 825 };
 826
 827 /**
 828  *      usb_alphatrack_init
 829  */
 830 static int __init usb_alphatrack_init(void)
 831 {
 832         int retval;
 833
 834         /* register this driver with the USB subsystem */
 835         retval = usb_register(&usb_alphatrack_driver);
 836         if (retval)
 837                 err("usb_register failed for the "__FILE__" driver. Error number %d\n", retval);
 838
 839         return retval;
 840 }
 841
 842 /**
 843  *      usb_alphatrack_exit
 844  */
 845 static void __exit usb_alphatrack_exit(void)
 846 {
 847         /* deregister this driver with the USB subsystem */
 848         usb_deregister(&usb_alphatrack_driver);
 849 }
 850
 851 module_init(usb_alphatrack_init);
 852 module_exit(usb_alphatrack_exit);
 853