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