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 /*
  34  * gameport_mutex protects entire gameport subsystem and is taken
  35  * every time gameport port or driver registrered or unregistered.
  36  */
  37 static DEFINE_MUTEX(gameport_mutex);
  38
  39 static LIST_HEAD(gameport_list);
  40
  41 static struct bus_type gameport_bus;
  42
  43 static void gameport_add_port(struct gameport *gameport);
  44 static void gameport_attach_driver(struct gameport_driver *drv);
  45 static void gameport_reconnect_port(struct gameport *gameport);
  46 static void gameport_disconnect_port(struct gameport *gameport);
  47
  48 #if defined(__i386__)
  49
  50 #include <asm/i8253.h>
  51
  52 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  53 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  54
  55 static unsigned int get_time_pit(void)
  56 {
  57         unsigned long flags;
  58         unsigned int count;
  59
  60         spin_lock_irqsave(&i8253_lock, flags);
  61         outb_p(0x00, 0x43);
  62         count = inb_p(0x40);
  63         count |= inb_p(0x40) << 8;
  64         spin_unlock_irqrestore(&i8253_lock, flags);
  65
  66         return count;
  67 }
  68
  69 #endif
  70
  71
  72
  73 /*
  74  * gameport_measure_speed() measures the gameport i/o speed.
  75  */
  76
  77 static int gameport_measure_speed(struct gameport *gameport)
  78 {
  79 #if defined(__i386__)
  80
  81         unsigned int i, t, t1, t2, t3, tx;
  82         unsigned long flags;
  83
  84         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  85                 return 0;
  86
  87         tx = 1 << 30;
  88
  89         for(i = 0; i < 50; i++) {
  90                 local_irq_save(flags);
  91                 GET_TIME(t1);
  92                 for (t = 0; t < 50; t++) gameport_read(gameport);
  93                 GET_TIME(t2);
  94                 GET_TIME(t3);
  95                 local_irq_restore(flags);
  96                 udelay(i * 10);
  97                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
  98         }
  99
 100         gameport_close(gameport);
 101         return 59659 / (tx < 1 ? 1 : tx);
 102
 103 #elif defined (__x86_64__)
 104
 105         unsigned int i, t;
 106         unsigned long tx, t1, t2, flags;
 107
 108         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 109                 return 0;
 110
 111         tx = 1 << 30;
 112
 113         for(i = 0; i < 50; i++) {
 114                 local_irq_save(flags);
 115                 rdtscl(t1);
 116                 for (t = 0; t < 50; t++) gameport_read(gameport);
 117                 rdtscl(t2);
 118                 local_irq_restore(flags);
 119                 udelay(i * 10);
 120                 if (t2 - t1 < tx) tx = t2 - t1;
 121         }
 122
 123         gameport_close(gameport);
 124         return (cpu_data(raw_smp_processor_id()).loops_per_jiffy *
 125                 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 126
 127 #else
 128
 129         unsigned int j, t = 0;
 130
 131         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 132                 return 0;
 133
 134         j = jiffies; while (j == jiffies);
 135         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 136
 137         gameport_close(gameport);
 138         return t * HZ / 1000;
 139
 140 #endif
 141 }
 142
 143 void gameport_start_polling(struct gameport *gameport)
 144 {
 145         spin_lock(&gameport->timer_lock);
 146
 147         if (!gameport->poll_cnt++) {
 148                 BUG_ON(!gameport->poll_handler);
 149                 BUG_ON(!gameport->poll_interval);
 150                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 151         }
 152
 153         spin_unlock(&gameport->timer_lock);
 154 }
 155 EXPORT_SYMBOL(gameport_start_polling);
 156
 157 void gameport_stop_polling(struct gameport *gameport)
 158 {
 159         spin_lock(&gameport->timer_lock);
 160
 161         if (!--gameport->poll_cnt)
 162                 del_timer(&gameport->poll_timer);
 163
 164         spin_unlock(&gameport->timer_lock);
 165 }
 166 EXPORT_SYMBOL(gameport_stop_polling);
 167
 168 static void gameport_run_poll_handler(unsigned long d)
 169 {
 170         struct gameport *gameport = (struct gameport *)d;
 171
 172         gameport->poll_handler(gameport);
 173         if (gameport->poll_cnt)
 174                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 175 }
 176
 177 /*
 178  * Basic gameport -> driver core mappings
 179  */
 180
 181 static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 182 {
 183         int error;
 184
 185         gameport->dev.driver = &drv->driver;
 186         if (drv->connect(gameport, drv)) {
 187                 gameport->dev.driver = NULL;
 188                 return -ENODEV;
 189         }
 190
 191         error = device_bind_driver(&gameport->dev);
 192         if (error) {
 193                 printk(KERN_WARNING
 194                         "gameport: device_bind_driver() failed "
 195                         "for %s (%s) and %s, error: %d\n",
 196                         gameport->phys, gameport->name,
 197                         drv->description, error);
 198                 drv->disconnect(gameport);
 199                 gameport->dev.driver = NULL;
 200                 return error;
 201         }
 202
 203         return 0;
 204 }
 205
 206 static void gameport_find_driver(struct gameport *gameport)
 207 {
 208         int error;
 209
 210         error = device_attach(&gameport->dev);
 211         if (error < 0)
 212                 printk(KERN_WARNING
 213                         "gameport: device_attach() failed for %s (%s), error: %d\n",
 214                         gameport->phys, gameport->name, error);
 215 }
 216
 217
 218 /*
 219  * Gameport event processing.
 220  */
 221
 222 enum gameport_event_type {
 223         GAMEPORT_REGISTER_PORT,
 224         GAMEPORT_ATTACH_DRIVER,
 225 };
 226
 227 struct gameport_event {
 228         enum gameport_event_type type;
 229         void *object;
 230         struct module *owner;
 231         struct list_head node;
 232 };
 233
 234 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 235 static LIST_HEAD(gameport_event_list);
 236 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 237 static struct task_struct *gameport_task;
 238
 239 static int gameport_queue_event(void *object, struct module *owner,
 240                                 enum gameport_event_type event_type)
 241 {
 242         unsigned long flags;
 243         struct gameport_event *event;
 244         int retval = 0;
 245
 246         spin_lock_irqsave(&gameport_event_lock, flags);
 247
 248         /*
 249          * Scan event list for the other events for the same gameport port,
 250          * starting with the most recent one. If event is the same we
 251          * do not need add new one. If event is of different type we
 252          * need to add this event and should not look further because
 253          * we need to preseve sequence of distinct events.
 254          */
 255         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 256                 if (event->object == object) {
 257                         if (event->type == event_type)
 258                                 goto out;
 259                         break;
 260                 }
 261         }
 262
 263         event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
 264         if (!event) {
 265                 printk(KERN_ERR
 266                         "gameport: Not enough memory to queue event %d\n",
 267                         event_type);
 268                 retval = -ENOMEM;
 269                 goto out;
 270         }
 271
 272         if (!try_module_get(owner)) {
 273                 printk(KERN_WARNING
 274                         "gameport: Can't get module reference, dropping event %d\n",
 275                         event_type);
 276                 kfree(event);
 277                 retval = -EINVAL;
 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
 288 out:
 289         spin_unlock_irqrestore(&gameport_event_lock, flags);
 290         return retval;
 291 }
 292
 293 static void gameport_free_event(struct gameport_event *event)
 294 {
 295         module_put(event->owner);
 296         kfree(event);
 297 }
 298
 299 static void gameport_remove_duplicate_events(struct gameport_event *event)
 300 {
 301         struct list_head *node, *next;
 302         struct gameport_event *e;
 303         unsigned long flags;
 304
 305         spin_lock_irqsave(&gameport_event_lock, flags);
 306
 307         list_for_each_safe(node, next, &gameport_event_list) {
 308                 e = list_entry(node, struct gameport_event, node);
 309                 if (event->object == e->object) {
 310                         /*
 311                          * If this event is of different type we should not
 312                          * look further - we only suppress duplicate events
 313                          * that were sent back-to-back.
 314                          */
 315                         if (event->type != e->type)
 316                                 break;
 317
 318                         list_del_init(node);
 319                         gameport_free_event(e);
 320                 }
 321         }
 322
 323         spin_unlock_irqrestore(&gameport_event_lock, flags);
 324 }
 325
 326 static struct gameport_event *gameport_get_event(void)
 327 {
 328         struct gameport_event *event;
 329         struct list_head *node;
 330         unsigned long flags;
 331
 332         spin_lock_irqsave(&gameport_event_lock, flags);
 333
 334         if (list_empty(&gameport_event_list)) {
 335                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 336                 return NULL;
 337         }
 338
 339         node = gameport_event_list.next;
 340         event = list_entry(node, struct gameport_event, node);
 341         list_del_init(node);
 342
 343         spin_unlock_irqrestore(&gameport_event_lock, flags);
 344
 345         return event;
 346 }
 347
 348 static void gameport_handle_event(void)
 349 {
 350         struct gameport_event *event;
 351
 352         mutex_lock(&gameport_mutex);
 353
 354         /*
 355          * Note that we handle only one event here to give swsusp
 356          * a chance to freeze kgameportd thread. Gameport events
 357          * should be pretty rare so we are not concerned about
 358          * taking performance hit.
 359          */
 360         if ((event = gameport_get_event())) {
 361
 362                 switch (event->type) {
 363                         case GAMEPORT_REGISTER_PORT:
 364                                 gameport_add_port(event->object);
 365                                 break;
 366
 367                         case GAMEPORT_ATTACH_DRIVER:
 368                                 gameport_attach_driver(event->object);
 369                                 break;
 370
 371                         default:
 372                                 break;
 373                 }
 374
 375                 gameport_remove_duplicate_events(event);
 376                 gameport_free_event(event);
 377         }
 378
 379         mutex_unlock(&gameport_mutex);
 380 }
 381
 382 /*
 383  * Remove all events that have been submitted for a given object,
 384  * be it a gameport port or a driver.
 385  */
 386 static void gameport_remove_pending_events(void *object)
 387 {
 388         struct list_head *node, *next;
 389         struct gameport_event *event;
 390         unsigned long flags;
 391
 392         spin_lock_irqsave(&gameport_event_lock, flags);
 393
 394         list_for_each_safe(node, next, &gameport_event_list) {
 395                 event = list_entry(node, struct gameport_event, node);
 396                 if (event->object == object) {
 397                         list_del_init(node);
 398                         gameport_free_event(event);
 399                 }
 400         }
 401
 402         spin_unlock_irqrestore(&gameport_event_lock, flags);
 403 }
 404
 405 /*
 406  * Destroy child gameport port (if any) that has not been fully registered yet.
 407  *
 408  * Note that we rely on the fact that port can have only one child and therefore
 409  * only one child registration request can be pending. Additionally, children
 410  * are registered by driver's connect() handler so there can't be a grandchild
 411  * pending registration together with a child.
 412  */
 413 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 414 {
 415         struct gameport_event *event;
 416         struct gameport *gameport, *child = NULL;
 417         unsigned long flags;
 418
 419         spin_lock_irqsave(&gameport_event_lock, flags);
 420
 421         list_for_each_entry(event, &gameport_event_list, node) {
 422                 if (event->type == GAMEPORT_REGISTER_PORT) {
 423                         gameport = event->object;
 424                         if (gameport->parent == parent) {
 425                                 child = gameport;
 426                                 break;
 427                         }
 428                 }
 429         }
 430
 431         spin_unlock_irqrestore(&gameport_event_lock, flags);
 432         return child;
 433 }
 434
 435 static int gameport_thread(void *nothing)
 436 {
 437         set_freezable();
 438         do {
 439                 gameport_handle_event();
 440                 wait_event_freezable(gameport_wait,
 441                         kthread_should_stop() || !list_empty(&gameport_event_list));
 442         } while (!kthread_should_stop());
 443
 444         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 445         return 0;
 446 }
 447
 448
 449 /*
 450  * Gameport port operations
 451  */
 452
 453 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 454 {
 455         struct gameport *gameport = to_gameport_port(dev);
 456         return sprintf(buf, "%s\n", gameport->name);
 457 }
 458
 459 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 460 {
 461         struct gameport *gameport = to_gameport_port(dev);
 462         struct device_driver *drv;
 463         int error;
 464
 465         error = mutex_lock_interruptible(&gameport_mutex);
 466         if (error)
 467                 return error;
 468
 469         if (!strncmp(buf, "none", count)) {
 470                 gameport_disconnect_port(gameport);
 471         } else if (!strncmp(buf, "reconnect", count)) {
 472                 gameport_reconnect_port(gameport);
 473         } else if (!strncmp(buf, "rescan", count)) {
 474                 gameport_disconnect_port(gameport);
 475                 gameport_find_driver(gameport);
 476         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 477                 gameport_disconnect_port(gameport);
 478                 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
 479                 put_driver(drv);
 480         } else {
 481                 error = -EINVAL;
 482         }
 483
 484         mutex_unlock(&gameport_mutex);
 485
 486         return error ? error : count;
 487 }
 488
 489 static struct device_attribute gameport_device_attrs[] = {
 490         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 491         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 492         __ATTR_NULL
 493 };
 494
 495 static void gameport_release_port(struct device *dev)
 496 {
 497         struct gameport *gameport = to_gameport_port(dev);
 498
 499         kfree(gameport);
 500         module_put(THIS_MODULE);
 501 }
 502
 503 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 504 {
 505         va_list args;
 506
 507         va_start(args, fmt);
 508         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 509         va_end(args);
 510 }
 511 EXPORT_SYMBOL(gameport_set_phys);
 512
 513 /*
 514  * Prepare gameport port for registration.
 515  */
 516 static void gameport_init_port(struct gameport *gameport)
 517 {
 518         static atomic_t gameport_no = ATOMIC_INIT(0);
 519
 520         __module_get(THIS_MODULE);
 521
 522         mutex_init(&gameport->drv_mutex);
 523         device_initialize(&gameport->dev);
 524         dev_set_name(&gameport->dev, "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 525         gameport->dev.bus = &gameport_bus;
 526         gameport->dev.release = gameport_release_port;
 527         if (gameport->parent)
 528                 gameport->dev.parent = &gameport->parent->dev;
 529
 530         INIT_LIST_HEAD(&gameport->node);
 531         spin_lock_init(&gameport->timer_lock);
 532         init_timer(&gameport->poll_timer);
 533         gameport->poll_timer.function = gameport_run_poll_handler;
 534         gameport->poll_timer.data = (unsigned long)gameport;
 535 }
 536
 537 /*
 538  * Complete gameport port registration.
 539  * Driver core will attempt to find appropriate driver for the port.
 540  */
 541 static void gameport_add_port(struct gameport *gameport)
 542 {
 543         int error;
 544
 545         if (gameport->parent)
 546                 gameport->parent->child = gameport;
 547
 548         gameport->speed = gameport_measure_speed(gameport);
 549
 550         list_add_tail(&gameport->node, &gameport_list);
 551
 552         if (gameport->io)
 553                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 554                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 555         else
 556                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 557                         gameport->name, gameport->phys, gameport->speed);
 558
 559         error = device_add(&gameport->dev);
 560         if (error)
 561                 printk(KERN_ERR
 562                         "gameport: device_add() failed for %s (%s), error: %d\n",
 563                         gameport->phys, gameport->name, error);
 564         else
 565                 gameport->registered = 1;
 566 }
 567
 568 /*
 569  * gameport_destroy_port() completes deregistration process and removes
 570  * port from the system
 571  */
 572 static void gameport_destroy_port(struct gameport *gameport)
 573 {
 574         struct gameport *child;
 575
 576         child = gameport_get_pending_child(gameport);
 577         if (child) {
 578                 gameport_remove_pending_events(child);
 579                 put_device(&child->dev);
 580         }
 581
 582         if (gameport->parent) {
 583                 gameport->parent->child = NULL;
 584                 gameport->parent = NULL;
 585         }
 586
 587         if (gameport->registered) {
 588                 device_del(&gameport->dev);
 589                 gameport->registered = 0;
 590         }
 591
 592         list_del_init(&gameport->node);
 593
 594         gameport_remove_pending_events(gameport);
 595         put_device(&gameport->dev);
 596 }
 597
 598 /*
 599  * Reconnect gameport port and all its children (re-initialize attached devices)
 600  */
 601 static void gameport_reconnect_port(struct gameport *gameport)
 602 {
 603         do {
 604                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 605                         gameport_disconnect_port(gameport);
 606                         gameport_find_driver(gameport);
 607                         /* Ok, old children are now gone, we are done */
 608                         break;
 609                 }
 610                 gameport = gameport->child;
 611         } while (gameport);
 612 }
 613
 614 /*
 615  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 616  * all child ports are unbound and destroyed.
 617  */
 618 static void gameport_disconnect_port(struct gameport *gameport)
 619 {
 620         struct gameport *s, *parent;
 621
 622         if (gameport->child) {
 623                 /*
 624                  * Children ports should be disconnected and destroyed
 625                  * first, staring with the leaf one, since we don't want
 626                  * to do recursion
 627                  */
 628                 for (s = gameport; s->child; s = s->child)
 629                         /* empty */;
 630
 631                 do {
 632                         parent = s->parent;
 633
 634                         device_release_driver(&s->dev);
 635                         gameport_destroy_port(s);
 636                 } while ((s = parent) != gameport);
 637         }
 638
 639         /*
 640          * Ok, no children left, now disconnect this port
 641          */
 642         device_release_driver(&gameport->dev);
 643 }
 644
 645 /*
 646  * Submits register request to kgameportd for subsequent execution.
 647  * Note that port registration is always asynchronous.
 648  */
 649 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 650 {
 651         gameport_init_port(gameport);
 652         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 653 }
 654 EXPORT_SYMBOL(__gameport_register_port);
 655
 656 /*
 657  * Synchronously unregisters gameport port.
 658  */
 659 void gameport_unregister_port(struct gameport *gameport)
 660 {
 661         mutex_lock(&gameport_mutex);
 662         gameport_disconnect_port(gameport);
 663         gameport_destroy_port(gameport);
 664         mutex_unlock(&gameport_mutex);
 665 }
 666 EXPORT_SYMBOL(gameport_unregister_port);
 667
 668
 669 /*
 670  * Gameport driver operations
 671  */
 672
 673 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 674 {
 675         struct gameport_driver *driver = to_gameport_driver(drv);
 676         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 677 }
 678
 679 static struct driver_attribute gameport_driver_attrs[] = {
 680         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 681         __ATTR_NULL
 682 };
 683
 684 static int gameport_driver_probe(struct device *dev)
 685 {
 686         struct gameport *gameport = to_gameport_port(dev);
 687         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 688
 689         drv->connect(gameport, drv);
 690         return gameport->drv ? 0 : -ENODEV;
 691 }
 692
 693 static int gameport_driver_remove(struct device *dev)
 694 {
 695         struct gameport *gameport = to_gameport_port(dev);
 696         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 697
 698         drv->disconnect(gameport);
 699         return 0;
 700 }
 701
 702 static void gameport_attach_driver(struct gameport_driver *drv)
 703 {
 704         int error;
 705
 706         error = driver_attach(&drv->driver);
 707         if (error)
 708                 printk(KERN_ERR
 709                         "gameport: driver_attach() failed for %s, error: %d\n",
 710                         drv->driver.name, error);
 711 }
 712
 713 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
 714                                 const char *mod_name)
 715 {
 716         int error;
 717
 718         drv->driver.bus = &gameport_bus;
 719         drv->driver.owner = owner;
 720         drv->driver.mod_name = mod_name;
 721
 722         /*
 723          * Temporarily disable automatic binding because probing
 724          * takes long time and we are better off doing it in kgameportd
 725          */
 726         drv->ignore = true;
 727
 728         error = driver_register(&drv->driver);
 729         if (error) {
 730                 printk(KERN_ERR
 731                         "gameport: driver_register() failed for %s, error: %d\n",
 732                         drv->driver.name, error);
 733                 return error;
 734         }
 735
 736         /*
 737          * Reset ignore flag and let kgameportd bind the driver to free ports
 738          */
 739         drv->ignore = false;
 740         error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
 741         if (error) {
 742                 driver_unregister(&drv->driver);
 743                 return error;
 744         }
 745
 746         return 0;
 747 }
 748 EXPORT_SYMBOL(__gameport_register_driver);
 749
 750 void gameport_unregister_driver(struct gameport_driver *drv)
 751 {
 752         struct gameport *gameport;
 753
 754         mutex_lock(&gameport_mutex);
 755
 756         drv->ignore = true;     /* so gameport_find_driver ignores it */
 757         gameport_remove_pending_events(drv);
 758
 759 start_over:
 760         list_for_each_entry(gameport, &gameport_list, node) {
 761                 if (gameport->drv == drv) {
 762                         gameport_disconnect_port(gameport);
 763                         gameport_find_driver(gameport);
 764                         /* we could've deleted some ports, restart */
 765                         goto start_over;
 766                 }
 767         }
 768
 769         driver_unregister(&drv->driver);
 770
 771         mutex_unlock(&gameport_mutex);
 772 }
 773 EXPORT_SYMBOL(gameport_unregister_driver);
 774
 775 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 776 {
 777         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 778
 779         return !gameport_drv->ignore;
 780 }
 781
 782 static struct bus_type gameport_bus = {
 783         .name           = "gameport",
 784         .dev_attrs      = gameport_device_attrs,
 785         .drv_attrs      = gameport_driver_attrs,
 786         .match          = gameport_bus_match,
 787         .probe          = gameport_driver_probe,
 788         .remove         = gameport_driver_remove,
 789 };
 790
 791 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 792 {
 793         mutex_lock(&gameport->drv_mutex);
 794         gameport->drv = drv;
 795         mutex_unlock(&gameport->drv_mutex);
 796 }
 797
 798 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 799 {
 800         if (gameport->open) {
 801                 if (gameport->open(gameport, mode)) {
 802                         return -1;
 803                 }
 804         } else {
 805                 if (mode != GAMEPORT_MODE_RAW)
 806                         return -1;
 807         }
 808
 809         gameport_set_drv(gameport, drv);
 810         return 0;
 811 }
 812 EXPORT_SYMBOL(gameport_open);
 813
 814 void gameport_close(struct gameport *gameport)
 815 {
 816         del_timer_sync(&gameport->poll_timer);
 817         gameport->poll_handler = NULL;
 818         gameport->poll_interval = 0;
 819         gameport_set_drv(gameport, NULL);
 820         if (gameport->close)
 821                 gameport->close(gameport);
 822 }
 823 EXPORT_SYMBOL(gameport_close);
 824
 825 static int __init gameport_init(void)
 826 {
 827         int error;
 828
 829         error = bus_register(&gameport_bus);
 830         if (error) {
 831                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 832                 return error;
 833         }
 834
 835         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 836         if (IS_ERR(gameport_task)) {
 837                 bus_unregister(&gameport_bus);
 838                 error = PTR_ERR(gameport_task);
 839                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 840                 return error;
 841         }
 842
 843         return 0;
 844 }
 845
 846 static void __exit gameport_exit(void)
 847 {
 848         bus_unregister(&gameport_bus);
 849         kthread_stop(gameport_task);
 850 }
 851
 852 subsys_initcall(gameport_init);
 853 module_exit(gameport_exit);