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
  25 /*#include <asm/io.h>*/
  26
  27 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  28 MODULE_DESCRIPTION("Generic gameport layer");
  29 MODULE_LICENSE("GPL");
  30
  31 EXPORT_SYMBOL(__gameport_register_port);
  32 EXPORT_SYMBOL(gameport_unregister_port);
  33 EXPORT_SYMBOL(__gameport_register_driver);
  34 EXPORT_SYMBOL(gameport_unregister_driver);
  35 EXPORT_SYMBOL(gameport_open);
  36 EXPORT_SYMBOL(gameport_close);
  37 EXPORT_SYMBOL(gameport_rescan);
  38 EXPORT_SYMBOL(gameport_cooked_read);
  39 EXPORT_SYMBOL(gameport_set_name);
  40 EXPORT_SYMBOL(gameport_set_phys);
  41 EXPORT_SYMBOL(gameport_start_polling);
  42 EXPORT_SYMBOL(gameport_stop_polling);
  43
  44 /*
  45  * gameport_sem protects entire gameport subsystem and is taken
  46  * every time gameport port or driver registrered or unregistered.
  47  */
  48 static DECLARE_MUTEX(gameport_sem);
  49
  50 static LIST_HEAD(gameport_list);
  51
  52 static struct bus_type gameport_bus = {
  53         .name = "gameport",
  54 };
  55
  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 * (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 void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 192 {
 193         down_write(&gameport_bus.subsys.rwsem);
 194
 195         gameport->dev.driver = &drv->driver;
 196         if (drv->connect(gameport, drv)) {
 197                 gameport->dev.driver = NULL;
 198                 goto out;
 199         }
 200         device_bind_driver(&gameport->dev);
 201 out:
 202         up_write(&gameport_bus.subsys.rwsem);
 203 }
 204
 205 static void gameport_release_driver(struct gameport *gameport)
 206 {
 207         down_write(&gameport_bus.subsys.rwsem);
 208         device_release_driver(&gameport->dev);
 209         up_write(&gameport_bus.subsys.rwsem);
 210 }
 211
 212 static void gameport_find_driver(struct gameport *gameport)
 213 {
 214         down_write(&gameport_bus.subsys.rwsem);
 215         device_attach(&gameport->dev);
 216         up_write(&gameport_bus.subsys.rwsem);
 217 }
 218
 219
 220 /*
 221  * Gameport event processing.
 222  */
 223
 224 enum gameport_event_type {
 225         GAMEPORT_RESCAN,
 226         GAMEPORT_RECONNECT,
 227         GAMEPORT_REGISTER_PORT,
 228         GAMEPORT_REGISTER_DRIVER,
 229 };
 230
 231 struct gameport_event {
 232         enum gameport_event_type type;
 233         void *object;
 234         struct module *owner;
 235         struct list_head node;
 236 };
 237
 238 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 239 static LIST_HEAD(gameport_event_list);
 240 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 241 static struct task_struct *gameport_task;
 242
 243 static void gameport_queue_event(void *object, struct module *owner,
 244                               enum gameport_event_type event_type)
 245 {
 246         unsigned long flags;
 247         struct gameport_event *event;
 248
 249         spin_lock_irqsave(&gameport_event_lock, flags);
 250
 251         /*
 252          * Scan event list for the other events for the same gameport port,
 253          * starting with the most recent one. If event is the same we
 254          * do not need add new one. If event is of different type we
 255          * need to add this event and should not look further because
 256          * we need to preseve sequence of distinct events.
 257          */
 258         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 259                 if (event->object == object) {
 260                         if (event->type == event_type)
 261                                 goto out;
 262                         break;
 263                 }
 264         }
 265
 266         if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
 267                 if (!try_module_get(owner)) {
 268                         printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
 269                         goto out;
 270                 }
 271
 272                 event->type = event_type;
 273                 event->object = object;
 274                 event->owner = owner;
 275
 276                 list_add_tail(&event->node, &gameport_event_list);
 277                 wake_up(&gameport_wait);
 278         } else {
 279                 printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
 280         }
 281 out:
 282         spin_unlock_irqrestore(&gameport_event_lock, flags);
 283 }
 284
 285 static void gameport_free_event(struct gameport_event *event)
 286 {
 287         module_put(event->owner);
 288         kfree(event);
 289 }
 290
 291 static void gameport_remove_duplicate_events(struct gameport_event *event)
 292 {
 293         struct list_head *node, *next;
 294         struct gameport_event *e;
 295         unsigned long flags;
 296
 297         spin_lock_irqsave(&gameport_event_lock, flags);
 298
 299         list_for_each_safe(node, next, &gameport_event_list) {
 300                 e = list_entry(node, struct gameport_event, node);
 301                 if (event->object == e->object) {
 302                         /*
 303                          * If this event is of different type we should not
 304                          * look further - we only suppress duplicate events
 305                          * that were sent back-to-back.
 306                          */
 307                         if (event->type != e->type)
 308                                 break;
 309
 310                         list_del_init(node);
 311                         gameport_free_event(e);
 312                 }
 313         }
 314
 315         spin_unlock_irqrestore(&gameport_event_lock, flags);
 316 }
 317
 318
 319 static struct gameport_event *gameport_get_event(void)
 320 {
 321         struct gameport_event *event;
 322         struct list_head *node;
 323         unsigned long flags;
 324
 325         spin_lock_irqsave(&gameport_event_lock, flags);
 326
 327         if (list_empty(&gameport_event_list)) {
 328                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 329                 return NULL;
 330         }
 331
 332         node = gameport_event_list.next;
 333         event = list_entry(node, struct gameport_event, node);
 334         list_del_init(node);
 335
 336         spin_unlock_irqrestore(&gameport_event_lock, flags);
 337
 338         return event;
 339 }
 340
 341 static void gameport_handle_events(void)
 342 {
 343         struct gameport_event *event;
 344         struct gameport_driver *gameport_drv;
 345
 346         down(&gameport_sem);
 347
 348         while ((event = gameport_get_event())) {
 349
 350                 switch (event->type) {
 351                         case GAMEPORT_REGISTER_PORT:
 352                                 gameport_add_port(event->object);
 353                                 break;
 354
 355                         case GAMEPORT_RECONNECT:
 356                                 gameport_reconnect_port(event->object);
 357                                 break;
 358
 359                         case GAMEPORT_RESCAN:
 360                                 gameport_disconnect_port(event->object);
 361                                 gameport_find_driver(event->object);
 362                                 break;
 363
 364                         case GAMEPORT_REGISTER_DRIVER:
 365                                 gameport_drv = event->object;
 366                                 driver_register(&gameport_drv->driver);
 367                                 break;
 368
 369                         default:
 370                                 break;
 371                 }
 372
 373                 gameport_remove_duplicate_events(event);
 374                 gameport_free_event(event);
 375         }
 376
 377         up(&gameport_sem);
 378 }
 379
 380 /*
 381  * Remove all events that have been submitted for a given gameport port.
 382  */
 383 static void gameport_remove_pending_events(struct gameport *gameport)
 384 {
 385         struct list_head *node, *next;
 386         struct gameport_event *event;
 387         unsigned long flags;
 388
 389         spin_lock_irqsave(&gameport_event_lock, flags);
 390
 391         list_for_each_safe(node, next, &gameport_event_list) {
 392                 event = list_entry(node, struct gameport_event, node);
 393                 if (event->object == gameport) {
 394                         list_del_init(node);
 395                         gameport_free_event(event);
 396                 }
 397         }
 398
 399         spin_unlock_irqrestore(&gameport_event_lock, flags);
 400 }
 401
 402 /*
 403  * Destroy child gameport port (if any) that has not been fully registered yet.
 404  *
 405  * Note that we rely on the fact that port can have only one child and therefore
 406  * only one child registration request can be pending. Additionally, children
 407  * are registered by driver's connect() handler so there can't be a grandchild
 408  * pending registration together with a child.
 409  */
 410 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 411 {
 412         struct gameport_event *event;
 413         struct gameport *gameport, *child = NULL;
 414         unsigned long flags;
 415
 416         spin_lock_irqsave(&gameport_event_lock, flags);
 417
 418         list_for_each_entry(event, &gameport_event_list, node) {
 419                 if (event->type == GAMEPORT_REGISTER_PORT) {
 420                         gameport = event->object;
 421                         if (gameport->parent == parent) {
 422                                 child = gameport;
 423                                 break;
 424                         }
 425                 }
 426         }
 427
 428         spin_unlock_irqrestore(&gameport_event_lock, flags);
 429         return child;
 430 }
 431
 432 static int gameport_thread(void *nothing)
 433 {
 434         do {
 435                 gameport_handle_events();
 436                 wait_event_interruptible(gameport_wait,
 437                         kthread_should_stop() || !list_empty(&gameport_event_list));
 438                 try_to_freeze();
 439         } while (!kthread_should_stop());
 440
 441         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 442         return 0;
 443 }
 444
 445
 446 /*
 447  * Gameport port operations
 448  */
 449
 450 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 451 {
 452         struct gameport *gameport = to_gameport_port(dev);
 453         return sprintf(buf, "%s\n", gameport->name);
 454 }
 455
 456 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 457 {
 458         struct gameport *gameport = to_gameport_port(dev);
 459         struct device_driver *drv;
 460         int retval;
 461
 462         retval = down_interruptible(&gameport_sem);
 463         if (retval)
 464                 return retval;
 465
 466         retval = count;
 467         if (!strncmp(buf, "none", count)) {
 468                 gameport_disconnect_port(gameport);
 469         } else if (!strncmp(buf, "reconnect", count)) {
 470                 gameport_reconnect_port(gameport);
 471         } else if (!strncmp(buf, "rescan", count)) {
 472                 gameport_disconnect_port(gameport);
 473                 gameport_find_driver(gameport);
 474         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 475                 gameport_disconnect_port(gameport);
 476                 gameport_bind_driver(gameport, to_gameport_driver(drv));
 477                 put_driver(drv);
 478         } else {
 479                 retval = -EINVAL;
 480         }
 481
 482         up(&gameport_sem);
 483
 484         return retval;
 485 }
 486
 487 static struct device_attribute gameport_device_attrs[] = {
 488         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 489         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 490         __ATTR_NULL
 491 };
 492
 493 static void gameport_release_port(struct device *dev)
 494 {
 495         struct gameport *gameport = to_gameport_port(dev);
 496
 497         kfree(gameport);
 498         module_put(THIS_MODULE);
 499 }
 500
 501 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 502 {
 503         va_list args;
 504
 505         va_start(args, fmt);
 506         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 507         va_end(args);
 508 }
 509
 510 /*
 511  * Prepare gameport port for registration.
 512  */
 513 static void gameport_init_port(struct gameport *gameport)
 514 {
 515         static atomic_t gameport_no = ATOMIC_INIT(0);
 516
 517         __module_get(THIS_MODULE);
 518
 519         init_MUTEX(&gameport->drv_sem);
 520         device_initialize(&gameport->dev);
 521         snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
 522                  "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 523         gameport->dev.bus = &gameport_bus;
 524         gameport->dev.release = gameport_release_port;
 525         if (gameport->parent)
 526                 gameport->dev.parent = &gameport->parent->dev;
 527
 528         spin_lock_init(&gameport->timer_lock);
 529         init_timer(&gameport->poll_timer);
 530         gameport->poll_timer.function = gameport_run_poll_handler;
 531         gameport->poll_timer.data = (unsigned long)gameport;
 532 }
 533
 534 /*
 535  * Complete gameport port registration.
 536  * Driver core will attempt to find appropriate driver for the port.
 537  */
 538 static void gameport_add_port(struct gameport *gameport)
 539 {
 540         if (gameport->parent)
 541                 gameport->parent->child = gameport;
 542
 543         gameport->speed = gameport_measure_speed(gameport);
 544
 545         list_add_tail(&gameport->node, &gameport_list);
 546
 547         if (gameport->io)
 548                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 549                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 550         else
 551                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 552                         gameport->name, gameport->phys, gameport->speed);
 553
 554         device_add(&gameport->dev);
 555         gameport->registered = 1;
 556 }
 557
 558 /*
 559  * gameport_destroy_port() completes deregistration process and removes
 560  * port from the system
 561  */
 562 static void gameport_destroy_port(struct gameport *gameport)
 563 {
 564         struct gameport *child;
 565
 566         child = gameport_get_pending_child(gameport);
 567         if (child) {
 568                 gameport_remove_pending_events(child);
 569                 put_device(&child->dev);
 570         }
 571
 572         if (gameport->parent) {
 573                 gameport->parent->child = NULL;
 574                 gameport->parent = NULL;
 575         }
 576
 577         if (gameport->registered) {
 578                 device_del(&gameport->dev);
 579                 list_del_init(&gameport->node);
 580                 gameport->registered = 0;
 581         }
 582
 583         gameport_remove_pending_events(gameport);
 584         put_device(&gameport->dev);
 585 }
 586
 587 /*
 588  * Reconnect gameport port and all its children (re-initialize attached devices)
 589  */
 590 static void gameport_reconnect_port(struct gameport *gameport)
 591 {
 592         do {
 593                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 594                         gameport_disconnect_port(gameport);
 595                         gameport_find_driver(gameport);
 596                         /* Ok, old children are now gone, we are done */
 597                         break;
 598                 }
 599                 gameport = gameport->child;
 600         } while (gameport);
 601 }
 602
 603 /*
 604  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 605  * all child ports are unbound and destroyed.
 606  */
 607 static void gameport_disconnect_port(struct gameport *gameport)
 608 {
 609         struct gameport *s, *parent;
 610
 611         if (gameport->child) {
 612                 /*
 613                  * Children ports should be disconnected and destroyed
 614                  * first, staring with the leaf one, since we don't want
 615                  * to do recursion
 616                  */
 617                 for (s = gameport; s->child; s = s->child)
 618                         /* empty */;
 619
 620                 do {
 621                         parent = s->parent;
 622
 623                         gameport_release_driver(s);
 624                         gameport_destroy_port(s);
 625                 } while ((s = parent) != gameport);
 626         }
 627
 628         /*
 629          * Ok, no children left, now disconnect this port
 630          */
 631         gameport_release_driver(gameport);
 632 }
 633
 634 void gameport_rescan(struct gameport *gameport)
 635 {
 636         gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
 637 }
 638
 639 void gameport_reconnect(struct gameport *gameport)
 640 {
 641         gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
 642 }
 643
 644 /*
 645  * Submits register request to kgameportd for subsequent execution.
 646  * Note that port registration is always asynchronous.
 647  */
 648 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 649 {
 650         gameport_init_port(gameport);
 651         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 652 }
 653
 654 /*
 655  * Synchronously unregisters gameport port.
 656  */
 657 void gameport_unregister_port(struct gameport *gameport)
 658 {
 659         down(&gameport_sem);
 660         gameport_disconnect_port(gameport);
 661         gameport_destroy_port(gameport);
 662         up(&gameport_sem);
 663 }
 664
 665
 666 /*
 667  * Gameport driver operations
 668  */
 669
 670 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 671 {
 672         struct gameport_driver *driver = to_gameport_driver(drv);
 673         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 674 }
 675
 676 static struct driver_attribute gameport_driver_attrs[] = {
 677         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 678         __ATTR_NULL
 679 };
 680
 681 static int gameport_driver_probe(struct device *dev)
 682 {
 683         struct gameport *gameport = to_gameport_port(dev);
 684         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 685
 686         drv->connect(gameport, drv);
 687         return gameport->drv ? 0 : -ENODEV;
 688 }
 689
 690 static int gameport_driver_remove(struct device *dev)
 691 {
 692         struct gameport *gameport = to_gameport_port(dev);
 693         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 694
 695         drv->disconnect(gameport);
 696         return 0;
 697 }
 698
 699 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
 700 {
 701         drv->driver.bus = &gameport_bus;
 702         drv->driver.probe = gameport_driver_probe;
 703         drv->driver.remove = gameport_driver_remove;
 704         gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
 705 }
 706
 707 void gameport_unregister_driver(struct gameport_driver *drv)
 708 {
 709         struct gameport *gameport;
 710
 711         down(&gameport_sem);
 712         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 713
 714 start_over:
 715         list_for_each_entry(gameport, &gameport_list, node) {
 716                 if (gameport->drv == drv) {
 717                         gameport_disconnect_port(gameport);
 718                         gameport_find_driver(gameport);
 719                         /* we could've deleted some ports, restart */
 720                         goto start_over;
 721                 }
 722         }
 723
 724         driver_unregister(&drv->driver);
 725         up(&gameport_sem);
 726 }
 727
 728 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 729 {
 730         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 731
 732         return !gameport_drv->ignore;
 733 }
 734
 735 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 736 {
 737         down(&gameport->drv_sem);
 738         gameport->drv = drv;
 739         up(&gameport->drv_sem);
 740 }
 741
 742 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 743 {
 744
 745         if (gameport->open) {
 746                 if (gameport->open(gameport, mode)) {
 747                         return -1;
 748                 }
 749         } else {
 750                 if (mode != GAMEPORT_MODE_RAW)
 751                         return -1;
 752         }
 753
 754         gameport_set_drv(gameport, drv);
 755         return 0;
 756 }
 757
 758 void gameport_close(struct gameport *gameport)
 759 {
 760         del_timer_sync(&gameport->poll_timer);
 761         gameport->poll_handler = NULL;
 762         gameport->poll_interval = 0;
 763         gameport_set_drv(gameport, NULL);
 764         if (gameport->close)
 765                 gameport->close(gameport);
 766 }
 767
 768 static int __init gameport_init(void)
 769 {
 770         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 771         if (IS_ERR(gameport_task)) {
 772                 printk(KERN_ERR "gameport: Failed to start kgameportd\n");
 773                 return PTR_ERR(gameport_task);
 774         }
 775
 776         gameport_bus.dev_attrs = gameport_device_attrs;
 777         gameport_bus.drv_attrs = gameport_driver_attrs;
 778         gameport_bus.match = gameport_bus_match;
 779         bus_register(&gameport_bus);
 780
 781         return 0;
 782 }
 783
 784 static void __exit gameport_exit(void)
 785 {
 786         bus_unregister(&gameport_bus);
 787         kthread_stop(gameport_task);
 788 }
 789
 790 module_init(gameport_init);
 791 module_exit(gameport_exit);