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