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