git.oblomov.eu Git - linux-2.6/blob - drivers/input/gameport/gameport.c

   1 /*
   2  * Generic gameport layer
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  * Copyright (c) 2005 Dmitry Torokhov
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  */
  13
  14 #include <linux/stddef.h>
  15 #include <linux/module.h>
  16 #include <linux/ioport.h>
  17 #include <linux/init.h>
  18 #include <linux/gameport.h>
  19 #include <linux/wait.h>
  20 #include <linux/slab.h>
  21 #include <linux/delay.h>
  22 #include <linux/kthread.h>
  23 #include <linux/sched.h>        /* HZ */
  24 #include <linux/mutex.h>
  25 #include <linux/freezer.h>
  26
  27 /*#include <asm/io.h>*/
  28
  29 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  30 MODULE_DESCRIPTION("Generic gameport layer");
  31 MODULE_LICENSE("GPL");
  32
  33 EXPORT_SYMBOL(__gameport_register_port);
  34 EXPORT_SYMBOL(gameport_unregister_port);
  35 EXPORT_SYMBOL(__gameport_register_driver);
  36 EXPORT_SYMBOL(gameport_unregister_driver);
  37 EXPORT_SYMBOL(gameport_open);
  38 EXPORT_SYMBOL(gameport_close);
  39 EXPORT_SYMBOL(gameport_set_phys);
  40 EXPORT_SYMBOL(gameport_start_polling);
  41 EXPORT_SYMBOL(gameport_stop_polling);
  42
  43 /*
  44  * gameport_mutex protects entire gameport subsystem and is taken
  45  * every time gameport port or driver registrered or unregistered.
  46  */
  47 static DEFINE_MUTEX(gameport_mutex);
  48
  49 static LIST_HEAD(gameport_list);
  50
  51 static struct bus_type gameport_bus;
  52
  53 static void gameport_add_driver(struct gameport_driver *drv);
  54 static void gameport_add_port(struct gameport *gameport);
  55 static void gameport_destroy_port(struct gameport *gameport);
  56 static void gameport_reconnect_port(struct gameport *gameport);
  57 static void gameport_disconnect_port(struct gameport *gameport);
  58
  59 #if defined(__i386__)
  60
  61 #include <asm/i8253.h>
  62
  63 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  64 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  65
  66 static unsigned int get_time_pit(void)
  67 {
  68         unsigned long flags;
  69         unsigned int count;
  70
  71         spin_lock_irqsave(&i8253_lock, flags);
  72         outb_p(0x00, 0x43);
  73         count = inb_p(0x40);
  74         count |= inb_p(0x40) << 8;
  75         spin_unlock_irqrestore(&i8253_lock, flags);
  76
  77         return count;
  78 }
  79
  80 #endif
  81
  82
  83
  84 /*
  85  * gameport_measure_speed() measures the gameport i/o speed.
  86  */
  87
  88 static int gameport_measure_speed(struct gameport *gameport)
  89 {
  90 #if defined(__i386__)
  91
  92         unsigned int i, t, t1, t2, t3, tx;
  93         unsigned long flags;
  94
  95         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  96                 return 0;
  97
  98         tx = 1 << 30;
  99
 100         for(i = 0; i < 50; i++) {
 101                 local_irq_save(flags);
 102                 GET_TIME(t1);
 103                 for (t = 0; t < 50; t++) gameport_read(gameport);
 104                 GET_TIME(t2);
 105                 GET_TIME(t3);
 106                 local_irq_restore(flags);
 107                 udelay(i * 10);
 108                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 109         }
 110
 111         gameport_close(gameport);
 112         return 59659 / (tx < 1 ? 1 : tx);
 113
 114 #elif defined (__x86_64__)
 115
 116         unsigned int i, t;
 117         unsigned long tx, t1, t2, flags;
 118
 119         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 120                 return 0;
 121
 122         tx = 1 << 30;
 123
 124         for(i = 0; i < 50; i++) {
 125                 local_irq_save(flags);
 126                 rdtscl(t1);
 127                 for (t = 0; t < 50; t++) gameport_read(gameport);
 128                 rdtscl(t2);
 129                 local_irq_restore(flags);
 130                 udelay(i * 10);
 131                 if (t2 - t1 < tx) tx = t2 - t1;
 132         }
 133
 134         gameport_close(gameport);
 135         return (cpu_data(raw_smp_processor_id()).loops_per_jiffy *
 136                 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 137
 138 #else
 139
 140         unsigned int j, t = 0;
 141
 142         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 143                 return 0;
 144
 145         j = jiffies; while (j == jiffies);
 146         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 147
 148         gameport_close(gameport);
 149         return t * HZ / 1000;
 150
 151 #endif
 152 }
 153
 154 void gameport_start_polling(struct gameport *gameport)
 155 {
 156         spin_lock(&gameport->timer_lock);
 157
 158         if (!gameport->poll_cnt++) {
 159                 BUG_ON(!gameport->poll_handler);
 160                 BUG_ON(!gameport->poll_interval);
 161                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 162         }
 163
 164         spin_unlock(&gameport->timer_lock);
 165 }
 166
 167 void gameport_stop_polling(struct gameport *gameport)
 168 {
 169         spin_lock(&gameport->timer_lock);
 170
 171         if (!--gameport->poll_cnt)
 172                 del_timer(&gameport->poll_timer);
 173
 174         spin_unlock(&gameport->timer_lock);
 175 }
 176
 177 static void gameport_run_poll_handler(unsigned long d)
 178 {
 179         struct gameport *gameport = (struct gameport *)d;
 180
 181         gameport->poll_handler(gameport);
 182         if (gameport->poll_cnt)
 183                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 184 }
 185
 186 /*
 187  * Basic gameport -> driver core mappings
 188  */
 189
 190 static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 191 {
 192         int error;
 193
 194         gameport->dev.driver = &drv->driver;
 195         if (drv->connect(gameport, drv)) {
 196                 gameport->dev.driver = NULL;
 197                 return -ENODEV;
 198         }
 199
 200         error = device_bind_driver(&gameport->dev);
 201         if (error) {
 202                 printk(KERN_WARNING
 203                         "gameport: device_bind_driver() failed "
 204                         "for %s (%s) and %s, error: %d\n",
 205                         gameport->phys, gameport->name,
 206                         drv->description, error);
 207                 drv->disconnect(gameport);
 208                 gameport->dev.driver = NULL;
 209                 return error;
 210         }
 211
 212         return 0;
 213 }
 214
 215 static void gameport_find_driver(struct gameport *gameport)
 216 {
 217         int error;
 218
 219         error = device_attach(&gameport->dev);
 220         if (error < 0)
 221                 printk(KERN_WARNING
 222                         "gameport: device_attach() failed for %s (%s), error: %d\n",
 223                         gameport->phys, gameport->name, error);
 224 }
 225
 226
 227 /*
 228  * Gameport event processing.
 229  */
 230
 231 enum gameport_event_type {
 232         GAMEPORT_REGISTER_PORT,
 233         GAMEPORT_REGISTER_DRIVER,
 234         GAMEPORT_ATTACH_DRIVER,
 235 };
 236
 237 struct gameport_event {
 238         enum gameport_event_type type;
 239         void *object;
 240         struct module *owner;
 241         struct list_head node;
 242 };
 243
 244 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 245 static LIST_HEAD(gameport_event_list);
 246 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 247 static struct task_struct *gameport_task;
 248
 249 static int gameport_queue_event(void *object, struct module *owner,
 250                                 enum gameport_event_type event_type)
 251 {
 252         unsigned long flags;
 253         struct gameport_event *event;
 254         int retval = 0;
 255
 256         spin_lock_irqsave(&gameport_event_lock, flags);
 257
 258         /*
 259          * Scan event list for the other events for the same gameport port,
 260          * starting with the most recent one. If event is the same we
 261          * do not need add new one. If event is of different type we
 262          * need to add this event and should not look further because
 263          * we need to preseve sequence of distinct events.
 264          */
 265         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 266                 if (event->object == object) {
 267                         if (event->type == event_type)
 268                                 goto out;
 269                         break;
 270                 }
 271         }
 272
 273         event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
 274         if (!event) {
 275                 printk(KERN_ERR
 276                         "gameport: Not enough memory to queue event %d\n",
 277                         event_type);
 278                 retval = -ENOMEM;
 279                 goto out;
 280         }
 281
 282         if (!try_module_get(owner)) {
 283                 printk(KERN_WARNING
 284                         "gameport: Can't get module reference, dropping event %d\n",
 285                         event_type);
 286                 kfree(event);
 287                 retval = -EINVAL;
 288                 goto out;
 289         }
 290
 291         event->type = event_type;
 292         event->object = object;
 293         event->owner = owner;
 294
 295         list_add_tail(&event->node, &gameport_event_list);
 296         wake_up(&gameport_wait);
 297
 298 out:
 299         spin_unlock_irqrestore(&gameport_event_lock, flags);
 300         return retval;
 301 }
 302
 303 static void gameport_free_event(struct gameport_event *event)
 304 {
 305         module_put(event->owner);
 306         kfree(event);
 307 }
 308
 309 static void gameport_remove_duplicate_events(struct gameport_event *event)
 310 {
 311         struct list_head *node, *next;
 312         struct gameport_event *e;
 313         unsigned long flags;
 314
 315         spin_lock_irqsave(&gameport_event_lock, flags);
 316
 317         list_for_each_safe(node, next, &gameport_event_list) {
 318                 e = list_entry(node, struct gameport_event, node);
 319                 if (event->object == e->object) {
 320                         /*
 321                          * If this event is of different type we should not
 322                          * look further - we only suppress duplicate events
 323                          * that were sent back-to-back.
 324                          */
 325                         if (event->type != e->type)
 326                                 break;
 327
 328                         list_del_init(node);
 329                         gameport_free_event(e);
 330                 }
 331         }
 332
 333         spin_unlock_irqrestore(&gameport_event_lock, flags);
 334 }
 335
 336 static struct gameport_event *gameport_get_event(void)
 337 {
 338         struct gameport_event *event;
 339         struct list_head *node;
 340         unsigned long flags;
 341
 342         spin_lock_irqsave(&gameport_event_lock, flags);
 343
 344         if (list_empty(&gameport_event_list)) {
 345                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 346                 return NULL;
 347         }
 348
 349         node = gameport_event_list.next;
 350         event = list_entry(node, struct gameport_event, node);
 351         list_del_init(node);
 352
 353         spin_unlock_irqrestore(&gameport_event_lock, flags);
 354
 355         return event;
 356 }
 357
 358 static void gameport_handle_event(void)
 359 {
 360         struct gameport_event *event;
 361
 362         mutex_lock(&gameport_mutex);
 363
 364         /*
 365          * Note that we handle only one event here to give swsusp
 366          * a chance to freeze kgameportd thread. Gameport events
 367          * should be pretty rare so we are not concerned about
 368          * taking performance hit.
 369          */
 370         if ((event = gameport_get_event())) {
 371
 372                 switch (event->type) {
 373                         case GAMEPORT_REGISTER_PORT:
 374                                 gameport_add_port(event->object);
 375                                 break;
 376
 377                         case GAMEPORT_REGISTER_DRIVER:
 378                                 gameport_add_driver(event->object);
 379                                 break;
 380
 381                         default:
 382                                 break;
 383                 }
 384
 385                 gameport_remove_duplicate_events(event);
 386                 gameport_free_event(event);
 387         }
 388
 389         mutex_unlock(&gameport_mutex);
 390 }
 391
 392 /*
 393  * Remove all events that have been submitted for a given object,
 394  * be it a gameport port or a driver.
 395  */
 396 static void gameport_remove_pending_events(void *object)
 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 == object) {
 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 /*
 656  * Submits register request to kgameportd for subsequent execution.
 657  * Note that port registration is always asynchronous.
 658  */
 659 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 660 {
 661         gameport_init_port(gameport);
 662         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 663 }
 664
 665 /*
 666  * Synchronously unregisters gameport port.
 667  */
 668 void gameport_unregister_port(struct gameport *gameport)
 669 {
 670         mutex_lock(&gameport_mutex);
 671         gameport_disconnect_port(gameport);
 672         gameport_destroy_port(gameport);
 673         mutex_unlock(&gameport_mutex);
 674 }
 675
 676
 677 /*
 678  * Gameport driver operations
 679  */
 680
 681 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 682 {
 683         struct gameport_driver *driver = to_gameport_driver(drv);
 684         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 685 }
 686
 687 static struct driver_attribute gameport_driver_attrs[] = {
 688         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 689         __ATTR_NULL
 690 };
 691
 692 static int gameport_driver_probe(struct device *dev)
 693 {
 694         struct gameport *gameport = to_gameport_port(dev);
 695         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 696
 697         drv->connect(gameport, drv);
 698         return gameport->drv ? 0 : -ENODEV;
 699 }
 700
 701 static int gameport_driver_remove(struct device *dev)
 702 {
 703         struct gameport *gameport = to_gameport_port(dev);
 704         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 705
 706         drv->disconnect(gameport);
 707         return 0;
 708 }
 709
 710 static void gameport_add_driver(struct gameport_driver *drv)
 711 {
 712         int error;
 713
 714         error = driver_register(&drv->driver);
 715         if (error)
 716                 printk(KERN_ERR
 717                         "gameport: driver_register() failed for %s, error: %d\n",
 718                         drv->driver.name, error);
 719 }
 720
 721 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
 722                                 const char *mod_name)
 723 {
 724         int error;
 725
 726         drv->driver.bus = &gameport_bus;
 727         drv->driver.owner = owner;
 728         drv->driver.mod_name = mod_name;
 729
 730         /*
 731          * Temporarily disable automatic binding because probing
 732          * takes long time and we are better off doing it in kgameportd
 733          */
 734         drv->ignore = 1;
 735
 736         error = driver_register(&drv->driver);
 737         if (error) {
 738                 printk(KERN_ERR
 739                         "gameport: driver_register() failed for %s, error: %d\n",
 740                         drv->driver.name, error);
 741                 return error;
 742         }
 743
 744         /*
 745          * Reset ignore flag and let kgameportd bind the driver to free ports
 746          */
 747         drv->ignore = 0;
 748         error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
 749         if (error) {
 750                 driver_unregister(&drv->driver);
 751                 return error;
 752         }
 753
 754         return 0;
 755 }
 756
 757 void gameport_unregister_driver(struct gameport_driver *drv)
 758 {
 759         struct gameport *gameport;
 760
 761         mutex_lock(&gameport_mutex);
 762
 763         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 764         gameport_remove_pending_events(drv);
 765
 766 start_over:
 767         list_for_each_entry(gameport, &gameport_list, node) {
 768                 if (gameport->drv == drv) {
 769                         gameport_disconnect_port(gameport);
 770                         gameport_find_driver(gameport);
 771                         /* we could've deleted some ports, restart */
 772                         goto start_over;
 773                 }
 774         }
 775
 776         driver_unregister(&drv->driver);
 777
 778         mutex_unlock(&gameport_mutex);
 779 }
 780
 781 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 782 {
 783         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 784
 785         return !gameport_drv->ignore;
 786 }
 787
 788 static struct bus_type gameport_bus = {
 789         .name           = "gameport",
 790         .dev_attrs      = gameport_device_attrs,
 791         .drv_attrs      = gameport_driver_attrs,
 792         .match          = gameport_bus_match,
 793         .probe          = gameport_driver_probe,
 794         .remove         = gameport_driver_remove,
 795 };
 796
 797 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 798 {
 799         mutex_lock(&gameport->drv_mutex);
 800         gameport->drv = drv;
 801         mutex_unlock(&gameport->drv_mutex);
 802 }
 803
 804 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 805 {
 806         if (gameport->open) {
 807                 if (gameport->open(gameport, mode)) {
 808                         return -1;
 809                 }
 810         } else {
 811                 if (mode != GAMEPORT_MODE_RAW)
 812                         return -1;
 813         }
 814
 815         gameport_set_drv(gameport, drv);
 816         return 0;
 817 }
 818
 819 void gameport_close(struct gameport *gameport)
 820 {
 821         del_timer_sync(&gameport->poll_timer);
 822         gameport->poll_handler = NULL;
 823         gameport->poll_interval = 0;
 824         gameport_set_drv(gameport, NULL);
 825         if (gameport->close)
 826                 gameport->close(gameport);
 827 }
 828
 829 static int __init gameport_init(void)
 830 {
 831         int error;
 832
 833         error = bus_register(&gameport_bus);
 834         if (error) {
 835                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 836                 return error;
 837         }
 838
 839         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 840         if (IS_ERR(gameport_task)) {
 841                 bus_unregister(&gameport_bus);
 842                 error = PTR_ERR(gameport_task);
 843                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 844                 return error;
 845         }
 846
 847         return 0;
 848 }
 849
 850 static void __exit gameport_exit(void)
 851 {
 852         bus_unregister(&gameport_bus);
 853         kthread_stop(gameport_task);
 854 }
 855
 856 subsys_initcall(gameport_init);
 857 module_exit(gameport_exit);