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