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