git.oblomov.eu Git - linux-2.6/blob - drivers/input/gameport/gameport.c

   1 /*
   2  * Generic gameport layer
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  * Copyright (c) 2005 Dmitry Torokhov
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  */
  13
  14 #include <linux/stddef.h>
  15 #include <linux/module.h>
  16 #include <linux/ioport.h>
  17 #include <linux/init.h>
  18 #include <linux/gameport.h>
  19 #include <linux/wait.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/kthread.h>
  24 #include <linux/sched.h>        /* HZ */
  25 #include <linux/mutex.h>
  26 #include <linux/freezer.h>
  27
  28 /*#include <asm/io.h>*/
  29
  30 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  31 MODULE_DESCRIPTION("Generic gameport layer");
  32 MODULE_LICENSE("GPL");
  33
  34 EXPORT_SYMBOL(__gameport_register_port);
  35 EXPORT_SYMBOL(gameport_unregister_port);
  36 EXPORT_SYMBOL(__gameport_register_driver);
  37 EXPORT_SYMBOL(gameport_unregister_driver);
  38 EXPORT_SYMBOL(gameport_open);
  39 EXPORT_SYMBOL(gameport_close);
  40 EXPORT_SYMBOL(gameport_rescan);
  41 EXPORT_SYMBOL(gameport_cooked_read);
  42 EXPORT_SYMBOL(gameport_set_name);
  43 EXPORT_SYMBOL(gameport_set_phys);
  44 EXPORT_SYMBOL(gameport_start_polling);
  45 EXPORT_SYMBOL(gameport_stop_polling);
  46
  47 /*
  48  * gameport_mutex protects entire gameport subsystem and is taken
  49  * every time gameport port or driver registrered or unregistered.
  50  */
  51 static DEFINE_MUTEX(gameport_mutex);
  52
  53 static LIST_HEAD(gameport_list);
  54
  55 static struct bus_type gameport_bus;
  56
  57 static void gameport_add_driver(struct gameport_driver *drv);
  58 static void gameport_add_port(struct gameport *gameport);
  59 static void gameport_destroy_port(struct gameport *gameport);
  60 static void gameport_reconnect_port(struct gameport *gameport);
  61 static void gameport_disconnect_port(struct gameport *gameport);
  62
  63 #if defined(__i386__)
  64
  65 #include <asm/i8253.h>
  66
  67 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  68 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  69
  70 static unsigned int get_time_pit(void)
  71 {
  72         unsigned long flags;
  73         unsigned int count;
  74
  75         spin_lock_irqsave(&i8253_lock, flags);
  76         outb_p(0x00, 0x43);
  77         count = inb_p(0x40);
  78         count |= inb_p(0x40) << 8;
  79         spin_unlock_irqrestore(&i8253_lock, flags);
  80
  81         return count;
  82 }
  83
  84 #endif
  85
  86
  87
  88 /*
  89  * gameport_measure_speed() measures the gameport i/o speed.
  90  */
  91
  92 static int gameport_measure_speed(struct gameport *gameport)
  93 {
  94 #if defined(__i386__)
  95
  96         unsigned int i, t, t1, t2, t3, tx;
  97         unsigned long flags;
  98
  99         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 100                 return 0;
 101
 102         tx = 1 << 30;
 103
 104         for(i = 0; i < 50; i++) {
 105                 local_irq_save(flags);
 106                 GET_TIME(t1);
 107                 for (t = 0; t < 50; t++) gameport_read(gameport);
 108                 GET_TIME(t2);
 109                 GET_TIME(t3);
 110                 local_irq_restore(flags);
 111                 udelay(i * 10);
 112                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 113         }
 114
 115         gameport_close(gameport);
 116         return 59659 / (tx < 1 ? 1 : tx);
 117
 118 #elif defined (__x86_64__)
 119
 120         unsigned int i, t;
 121         unsigned long tx, t1, t2, flags;
 122
 123         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 124                 return 0;
 125
 126         tx = 1 << 30;
 127
 128         for(i = 0; i < 50; i++) {
 129                 local_irq_save(flags);
 130                 rdtscl(t1);
 131                 for (t = 0; t < 50; t++) gameport_read(gameport);
 132                 rdtscl(t2);
 133                 local_irq_restore(flags);
 134                 udelay(i * 10);
 135                 if (t2 - t1 < tx) tx = t2 - t1;
 136         }
 137
 138         gameport_close(gameport);
 139         return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 140
 141 #else
 142
 143         unsigned int j, t = 0;
 144
 145         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 146                 return 0;
 147
 148         j = jiffies; while (j == jiffies);
 149         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 150
 151         gameport_close(gameport);
 152         return t * HZ / 1000;
 153
 154 #endif
 155 }
 156
 157 void gameport_start_polling(struct gameport *gameport)
 158 {
 159         spin_lock(&gameport->timer_lock);
 160
 161         if (!gameport->poll_cnt++) {
 162                 BUG_ON(!gameport->poll_handler);
 163                 BUG_ON(!gameport->poll_interval);
 164                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 165         }
 166
 167         spin_unlock(&gameport->timer_lock);
 168 }
 169
 170 void gameport_stop_polling(struct gameport *gameport)
 171 {
 172         spin_lock(&gameport->timer_lock);
 173
 174         if (!--gameport->poll_cnt)
 175                 del_timer(&gameport->poll_timer);
 176
 177         spin_unlock(&gameport->timer_lock);
 178 }
 179
 180 static void gameport_run_poll_handler(unsigned long d)
 181 {
 182         struct gameport *gameport = (struct gameport *)d;
 183
 184         gameport->poll_handler(gameport);
 185         if (gameport->poll_cnt)
 186                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 187 }
 188
 189 /*
 190  * Basic gameport -> driver core mappings
 191  */
 192
 193 static void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 194 {
 195         int error;
 196
 197         down_write(&gameport_bus.subsys.rwsem);
 198
 199         gameport->dev.driver = &drv->driver;
 200         if (drv->connect(gameport, drv)) {
 201                 gameport->dev.driver = NULL;
 202                 goto out;
 203         }
 204
 205         error = device_bind_driver(&gameport->dev);
 206         if (error) {
 207                 printk(KERN_WARNING
 208                         "gameport: device_bind_driver() failed "
 209                         "for %s (%s) and %s, error: %d\n",
 210                         gameport->phys, gameport->name,
 211                         drv->description, error);
 212                 drv->disconnect(gameport);
 213                 gameport->dev.driver = NULL;
 214                 goto out;
 215         }
 216
 217  out:
 218         up_write(&gameport_bus.subsys.rwsem);
 219 }
 220
 221 static void gameport_release_driver(struct gameport *gameport)
 222 {
 223         down_write(&gameport_bus.subsys.rwsem);
 224         device_release_driver(&gameport->dev);
 225         up_write(&gameport_bus.subsys.rwsem);
 226 }
 227
 228 static void gameport_find_driver(struct gameport *gameport)
 229 {
 230         int error;
 231
 232         down_write(&gameport_bus.subsys.rwsem);
 233         error = device_attach(&gameport->dev);
 234         if (error < 0)
 235                 printk(KERN_WARNING
 236                         "gameport: device_attach() failed for %s (%s), error: %d\n",
 237                         gameport->phys, gameport->name, error);
 238         up_write(&gameport_bus.subsys.rwsem);
 239 }
 240
 241
 242 /*
 243  * Gameport event processing.
 244  */
 245
 246 enum gameport_event_type {
 247         GAMEPORT_RESCAN,
 248         GAMEPORT_RECONNECT,
 249         GAMEPORT_REGISTER_PORT,
 250         GAMEPORT_REGISTER_DRIVER,
 251 };
 252
 253 struct gameport_event {
 254         enum gameport_event_type type;
 255         void *object;
 256         struct module *owner;
 257         struct list_head node;
 258 };
 259
 260 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 261 static LIST_HEAD(gameport_event_list);
 262 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 263 static struct task_struct *gameport_task;
 264
 265 static void gameport_queue_event(void *object, struct module *owner,
 266                               enum gameport_event_type event_type)
 267 {
 268         unsigned long flags;
 269         struct gameport_event *event;
 270
 271         spin_lock_irqsave(&gameport_event_lock, flags);
 272
 273         /*
 274          * Scan event list for the other events for the same gameport port,
 275          * starting with the most recent one. If event is the same we
 276          * do not need add new one. If event is of different type we
 277          * need to add this event and should not look further because
 278          * we need to preseve sequence of distinct events.
 279          */
 280         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 281                 if (event->object == object) {
 282                         if (event->type == event_type)
 283                                 goto out;
 284                         break;
 285                 }
 286         }
 287
 288         if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
 289                 if (!try_module_get(owner)) {
 290                         printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
 291                         kfree(event);
 292                         goto out;
 293                 }
 294
 295                 event->type = event_type;
 296                 event->object = object;
 297                 event->owner = owner;
 298
 299                 list_add_tail(&event->node, &gameport_event_list);
 300                 wake_up(&gameport_wait);
 301         } else {
 302                 printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
 303         }
 304 out:
 305         spin_unlock_irqrestore(&gameport_event_lock, flags);
 306 }
 307
 308 static void gameport_free_event(struct gameport_event *event)
 309 {
 310         module_put(event->owner);
 311         kfree(event);
 312 }
 313
 314 static void gameport_remove_duplicate_events(struct gameport_event *event)
 315 {
 316         struct list_head *node, *next;
 317         struct gameport_event *e;
 318         unsigned long flags;
 319
 320         spin_lock_irqsave(&gameport_event_lock, flags);
 321
 322         list_for_each_safe(node, next, &gameport_event_list) {
 323                 e = list_entry(node, struct gameport_event, node);
 324                 if (event->object == e->object) {
 325                         /*
 326                          * If this event is of different type we should not
 327                          * look further - we only suppress duplicate events
 328                          * that were sent back-to-back.
 329                          */
 330                         if (event->type != e->type)
 331                                 break;
 332
 333                         list_del_init(node);
 334                         gameport_free_event(e);
 335                 }
 336         }
 337
 338         spin_unlock_irqrestore(&gameport_event_lock, flags);
 339 }
 340
 341 static struct gameport_event *gameport_get_event(void)
 342 {
 343         struct gameport_event *event;
 344         struct list_head *node;
 345         unsigned long flags;
 346
 347         spin_lock_irqsave(&gameport_event_lock, flags);
 348
 349         if (list_empty(&gameport_event_list)) {
 350                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 351                 return NULL;
 352         }
 353
 354         node = gameport_event_list.next;
 355         event = list_entry(node, struct gameport_event, node);
 356         list_del_init(node);
 357
 358         spin_unlock_irqrestore(&gameport_event_lock, flags);
 359
 360         return event;
 361 }
 362
 363 static void gameport_handle_event(void)
 364 {
 365         struct gameport_event *event;
 366
 367         mutex_lock(&gameport_mutex);
 368
 369         /*
 370          * Note that we handle only one event here to give swsusp
 371          * a chance to freeze kgameportd thread. Gameport events
 372          * should be pretty rare so we are not concerned about
 373          * taking performance hit.
 374          */
 375         if ((event = gameport_get_event())) {
 376
 377                 switch (event->type) {
 378                         case GAMEPORT_REGISTER_PORT:
 379                                 gameport_add_port(event->object);
 380                                 break;
 381
 382                         case GAMEPORT_RECONNECT:
 383                                 gameport_reconnect_port(event->object);
 384                                 break;
 385
 386                         case GAMEPORT_RESCAN:
 387                                 gameport_disconnect_port(event->object);
 388                                 gameport_find_driver(event->object);
 389                                 break;
 390
 391                         case GAMEPORT_REGISTER_DRIVER:
 392                                 gameport_add_driver(event->object);
 393                                 break;
 394
 395                         default:
 396                                 break;
 397                 }
 398
 399                 gameport_remove_duplicate_events(event);
 400                 gameport_free_event(event);
 401         }
 402
 403         mutex_unlock(&gameport_mutex);
 404 }
 405
 406 /*
 407  * Remove all events that have been submitted for a given gameport port.
 408  */
 409 static void gameport_remove_pending_events(struct gameport *gameport)
 410 {
 411         struct list_head *node, *next;
 412         struct gameport_event *event;
 413         unsigned long flags;
 414
 415         spin_lock_irqsave(&gameport_event_lock, flags);
 416
 417         list_for_each_safe(node, next, &gameport_event_list) {
 418                 event = list_entry(node, struct gameport_event, node);
 419                 if (event->object == gameport) {
 420                         list_del_init(node);
 421                         gameport_free_event(event);
 422                 }
 423         }
 424
 425         spin_unlock_irqrestore(&gameport_event_lock, flags);
 426 }
 427
 428 /*
 429  * Destroy child gameport port (if any) that has not been fully registered yet.
 430  *
 431  * Note that we rely on the fact that port can have only one child and therefore
 432  * only one child registration request can be pending. Additionally, children
 433  * are registered by driver's connect() handler so there can't be a grandchild
 434  * pending registration together with a child.
 435  */
 436 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 437 {
 438         struct gameport_event *event;
 439         struct gameport *gameport, *child = NULL;
 440         unsigned long flags;
 441
 442         spin_lock_irqsave(&gameport_event_lock, flags);
 443
 444         list_for_each_entry(event, &gameport_event_list, node) {
 445                 if (event->type == GAMEPORT_REGISTER_PORT) {
 446                         gameport = event->object;
 447                         if (gameport->parent == parent) {
 448                                 child = gameport;
 449                                 break;
 450                         }
 451                 }
 452         }
 453
 454         spin_unlock_irqrestore(&gameport_event_lock, flags);
 455         return child;
 456 }
 457
 458 static int gameport_thread(void *nothing)
 459 {
 460         do {
 461                 gameport_handle_event();
 462                 wait_event_interruptible(gameport_wait,
 463                         kthread_should_stop() || !list_empty(&gameport_event_list));
 464                 try_to_freeze();
 465         } while (!kthread_should_stop());
 466
 467         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 468         return 0;
 469 }
 470
 471
 472 /*
 473  * Gameport port operations
 474  */
 475
 476 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 477 {
 478         struct gameport *gameport = to_gameport_port(dev);
 479         return sprintf(buf, "%s\n", gameport->name);
 480 }
 481
 482 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 483 {
 484         struct gameport *gameport = to_gameport_port(dev);
 485         struct device_driver *drv;
 486         int retval;
 487
 488         retval = mutex_lock_interruptible(&gameport_mutex);
 489         if (retval)
 490                 return retval;
 491
 492         retval = count;
 493         if (!strncmp(buf, "none", count)) {
 494                 gameport_disconnect_port(gameport);
 495         } else if (!strncmp(buf, "reconnect", count)) {
 496                 gameport_reconnect_port(gameport);
 497         } else if (!strncmp(buf, "rescan", count)) {
 498                 gameport_disconnect_port(gameport);
 499                 gameport_find_driver(gameport);
 500         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 501                 gameport_disconnect_port(gameport);
 502                 gameport_bind_driver(gameport, to_gameport_driver(drv));
 503                 put_driver(drv);
 504         } else {
 505                 retval = -EINVAL;
 506         }
 507
 508         mutex_unlock(&gameport_mutex);
 509
 510         return retval;
 511 }
 512
 513 static struct device_attribute gameport_device_attrs[] = {
 514         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 515         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 516         __ATTR_NULL
 517 };
 518
 519 static void gameport_release_port(struct device *dev)
 520 {
 521         struct gameport *gameport = to_gameport_port(dev);
 522
 523         kfree(gameport);
 524         module_put(THIS_MODULE);
 525 }
 526
 527 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 528 {
 529         va_list args;
 530
 531         va_start(args, fmt);
 532         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 533         va_end(args);
 534 }
 535
 536 /*
 537  * Prepare gameport port for registration.
 538  */
 539 static void gameport_init_port(struct gameport *gameport)
 540 {
 541         static atomic_t gameport_no = ATOMIC_INIT(0);
 542
 543         __module_get(THIS_MODULE);
 544
 545         mutex_init(&gameport->drv_mutex);
 546         device_initialize(&gameport->dev);
 547         snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
 548                  "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 549         gameport->dev.bus = &gameport_bus;
 550         gameport->dev.release = gameport_release_port;
 551         if (gameport->parent)
 552                 gameport->dev.parent = &gameport->parent->dev;
 553
 554         INIT_LIST_HEAD(&gameport->node);
 555         spin_lock_init(&gameport->timer_lock);
 556         init_timer(&gameport->poll_timer);
 557         gameport->poll_timer.function = gameport_run_poll_handler;
 558         gameport->poll_timer.data = (unsigned long)gameport;
 559 }
 560
 561 /*
 562  * Complete gameport port registration.
 563  * Driver core will attempt to find appropriate driver for the port.
 564  */
 565 static void gameport_add_port(struct gameport *gameport)
 566 {
 567         int error;
 568
 569         if (gameport->parent)
 570                 gameport->parent->child = gameport;
 571
 572         gameport->speed = gameport_measure_speed(gameport);
 573
 574         list_add_tail(&gameport->node, &gameport_list);
 575
 576         if (gameport->io)
 577                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 578                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 579         else
 580                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 581                         gameport->name, gameport->phys, gameport->speed);
 582
 583         error = device_add(&gameport->dev);
 584         if (error)
 585                 printk(KERN_ERR
 586                         "gameport: device_add() failed for %s (%s), error: %d\n",
 587                         gameport->phys, gameport->name, error);
 588         else
 589                 gameport->registered = 1;
 590 }
 591
 592 /*
 593  * gameport_destroy_port() completes deregistration process and removes
 594  * port from the system
 595  */
 596 static void gameport_destroy_port(struct gameport *gameport)
 597 {
 598         struct gameport *child;
 599
 600         child = gameport_get_pending_child(gameport);
 601         if (child) {
 602                 gameport_remove_pending_events(child);
 603                 put_device(&child->dev);
 604         }
 605
 606         if (gameport->parent) {
 607                 gameport->parent->child = NULL;
 608                 gameport->parent = NULL;
 609         }
 610
 611         if (gameport->registered) {
 612                 device_del(&gameport->dev);
 613                 gameport->registered = 0;
 614         }
 615
 616         list_del_init(&gameport->node);
 617
 618         gameport_remove_pending_events(gameport);
 619         put_device(&gameport->dev);
 620 }
 621
 622 /*
 623  * Reconnect gameport port and all its children (re-initialize attached devices)
 624  */
 625 static void gameport_reconnect_port(struct gameport *gameport)
 626 {
 627         do {
 628                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 629                         gameport_disconnect_port(gameport);
 630                         gameport_find_driver(gameport);
 631                         /* Ok, old children are now gone, we are done */
 632                         break;
 633                 }
 634                 gameport = gameport->child;
 635         } while (gameport);
 636 }
 637
 638 /*
 639  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 640  * all child ports are unbound and destroyed.
 641  */
 642 static void gameport_disconnect_port(struct gameport *gameport)
 643 {
 644         struct gameport *s, *parent;
 645
 646         if (gameport->child) {
 647                 /*
 648                  * Children ports should be disconnected and destroyed
 649                  * first, staring with the leaf one, since we don't want
 650                  * to do recursion
 651                  */
 652                 for (s = gameport; s->child; s = s->child)
 653                         /* empty */;
 654
 655                 do {
 656                         parent = s->parent;
 657
 658                         gameport_release_driver(s);
 659                         gameport_destroy_port(s);
 660                 } while ((s = parent) != gameport);
 661         }
 662
 663         /*
 664          * Ok, no children left, now disconnect this port
 665          */
 666         gameport_release_driver(gameport);
 667 }
 668
 669 void gameport_rescan(struct gameport *gameport)
 670 {
 671         gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
 672 }
 673
 674 void gameport_reconnect(struct gameport *gameport)
 675 {
 676         gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
 677 }
 678
 679 /*
 680  * Submits register request to kgameportd for subsequent execution.
 681  * Note that port registration is always asynchronous.
 682  */
 683 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 684 {
 685         gameport_init_port(gameport);
 686         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 687 }
 688
 689 /*
 690  * Synchronously unregisters gameport port.
 691  */
 692 void gameport_unregister_port(struct gameport *gameport)
 693 {
 694         mutex_lock(&gameport_mutex);
 695         gameport_disconnect_port(gameport);
 696         gameport_destroy_port(gameport);
 697         mutex_unlock(&gameport_mutex);
 698 }
 699
 700
 701 /*
 702  * Gameport driver operations
 703  */
 704
 705 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 706 {
 707         struct gameport_driver *driver = to_gameport_driver(drv);
 708         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 709 }
 710
 711 static struct driver_attribute gameport_driver_attrs[] = {
 712         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 713         __ATTR_NULL
 714 };
 715
 716 static int gameport_driver_probe(struct device *dev)
 717 {
 718         struct gameport *gameport = to_gameport_port(dev);
 719         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 720
 721         drv->connect(gameport, drv);
 722         return gameport->drv ? 0 : -ENODEV;
 723 }
 724
 725 static int gameport_driver_remove(struct device *dev)
 726 {
 727         struct gameport *gameport = to_gameport_port(dev);
 728         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 729
 730         drv->disconnect(gameport);
 731         return 0;
 732 }
 733
 734 static struct bus_type gameport_bus = {
 735         .name   = "gameport",
 736         .probe  = gameport_driver_probe,
 737         .remove = gameport_driver_remove,
 738 };
 739
 740 static void gameport_add_driver(struct gameport_driver *drv)
 741 {
 742         int error;
 743
 744         error = driver_register(&drv->driver);
 745         if (error)
 746                 printk(KERN_ERR
 747                         "gameport: driver_register() failed for %s, error: %d\n",
 748                         drv->driver.name, error);
 749 }
 750
 751 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
 752 {
 753         drv->driver.bus = &gameport_bus;
 754         gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
 755 }
 756
 757 void gameport_unregister_driver(struct gameport_driver *drv)
 758 {
 759         struct gameport *gameport;
 760
 761         mutex_lock(&gameport_mutex);
 762         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 763
 764 start_over:
 765         list_for_each_entry(gameport, &gameport_list, node) {
 766                 if (gameport->drv == drv) {
 767                         gameport_disconnect_port(gameport);
 768                         gameport_find_driver(gameport);
 769                         /* we could've deleted some ports, restart */
 770                         goto start_over;
 771                 }
 772         }
 773
 774         driver_unregister(&drv->driver);
 775         mutex_unlock(&gameport_mutex);
 776 }
 777
 778 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 779 {
 780         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 781
 782         return !gameport_drv->ignore;
 783 }
 784
 785 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 786 {
 787         mutex_lock(&gameport->drv_mutex);
 788         gameport->drv = drv;
 789         mutex_unlock(&gameport->drv_mutex);
 790 }
 791
 792 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 793 {
 794
 795         if (gameport->open) {
 796                 if (gameport->open(gameport, mode)) {
 797                         return -1;
 798                 }
 799         } else {
 800                 if (mode != GAMEPORT_MODE_RAW)
 801                         return -1;
 802         }
 803
 804         gameport_set_drv(gameport, drv);
 805         return 0;
 806 }
 807
 808 void gameport_close(struct gameport *gameport)
 809 {
 810         del_timer_sync(&gameport->poll_timer);
 811         gameport->poll_handler = NULL;
 812         gameport->poll_interval = 0;
 813         gameport_set_drv(gameport, NULL);
 814         if (gameport->close)
 815                 gameport->close(gameport);
 816 }
 817
 818 static int __init gameport_init(void)
 819 {
 820         int error;
 821
 822         gameport_bus.dev_attrs = gameport_device_attrs;
 823         gameport_bus.drv_attrs = gameport_driver_attrs;
 824         gameport_bus.match = gameport_bus_match;
 825         error = bus_register(&gameport_bus);
 826         if (error) {
 827                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 828                 return error;
 829         }
 830
 831         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 832         if (IS_ERR(gameport_task)) {
 833                 bus_unregister(&gameport_bus);
 834                 error = PTR_ERR(gameport_task);
 835                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 836                 return error;
 837         }
 838
 839         return 0;
 840 }
 841
 842 static void __exit gameport_exit(void)
 843 {
 844         bus_unregister(&gameport_bus);
 845         kthread_stop(gameport_task);
 846 }
 847
 848 subsys_initcall(gameport_init);
 849 module_exit(gameport_exit);