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