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/interrupt.h>
  24 #include <linux/sched.h>        /* HZ */
  25 #include <linux/mutex.h>
  26 #include <linux/freezer.h>
  27
  28 /*#include <asm/io.h>*/
  29
  30 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  31 MODULE_DESCRIPTION("Generic gameport layer");
  32 MODULE_LICENSE("GPL");
  33
  34 EXPORT_SYMBOL(__gameport_register_port);
  35 EXPORT_SYMBOL(gameport_unregister_port);
  36 EXPORT_SYMBOL(__gameport_register_driver);
  37 EXPORT_SYMBOL(gameport_unregister_driver);
  38 EXPORT_SYMBOL(gameport_open);
  39 EXPORT_SYMBOL(gameport_close);
  40 EXPORT_SYMBOL(gameport_set_phys);
  41 EXPORT_SYMBOL(gameport_start_polling);
  42 EXPORT_SYMBOL(gameport_stop_polling);
  43
  44 /*
  45  * gameport_mutex protects entire gameport subsystem and is taken
  46  * every time gameport port or driver registrered or unregistered.
  47  */
  48 static DEFINE_MUTEX(gameport_mutex);
  49
  50 static LIST_HEAD(gameport_list);
  51
  52 static struct bus_type gameport_bus;
  53
  54 static void gameport_add_port(struct gameport *gameport);
  55 static void gameport_attach_driver(struct gameport_driver *drv);
  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_nort(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_nort(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_nort(flags);
 126                 rdtscl(t1);
 127                 for (t = 0; t < 50; t++) gameport_read(gameport);
 128                 rdtscl(t2);
 129                 local_irq_restore_nort(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_ATTACH_DRIVER,
 234 };
 235
 236 struct gameport_event {
 237         enum gameport_event_type type;
 238         void *object;
 239         struct module *owner;
 240         struct list_head node;
 241 };
 242
 243 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 244 static LIST_HEAD(gameport_event_list);
 245 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 246 static struct task_struct *gameport_task;
 247
 248 static int gameport_queue_event(void *object, struct module *owner,
 249                                 enum gameport_event_type event_type)
 250 {
 251         unsigned long flags;
 252         struct gameport_event *event;
 253         int retval = 0;
 254
 255         spin_lock_irqsave(&gameport_event_lock, flags);
 256
 257         /*
 258          * Scan event list for the other events for the same gameport port,
 259          * starting with the most recent one. If event is the same we
 260          * do not need add new one. If event is of different type we
 261          * need to add this event and should not look further because
 262          * we need to preseve sequence of distinct events.
 263          */
 264         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 265                 if (event->object == object) {
 266                         if (event->type == event_type)
 267                                 goto out;
 268                         break;
 269                 }
 270         }
 271
 272         event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
 273         if (!event) {
 274                 printk(KERN_ERR
 275                         "gameport: Not enough memory to queue event %d\n",
 276                         event_type);
 277                 retval = -ENOMEM;
 278                 goto out;
 279         }
 280
 281         if (!try_module_get(owner)) {
 282                 printk(KERN_WARNING
 283                         "gameport: Can't get module reference, dropping event %d\n",
 284                         event_type);
 285                 kfree(event);
 286                 retval = -EINVAL;
 287                 goto out;
 288         }
 289
 290         event->type = event_type;
 291         event->object = object;
 292         event->owner = owner;
 293
 294         list_add_tail(&event->node, &gameport_event_list);
 295         wake_up(&gameport_wait);
 296
 297 out:
 298         spin_unlock_irqrestore(&gameport_event_lock, flags);
 299         return retval;
 300 }
 301
 302 static void gameport_free_event(struct gameport_event *event)
 303 {
 304         module_put(event->owner);
 305         kfree(event);
 306 }
 307
 308 static void gameport_remove_duplicate_events(struct gameport_event *event)
 309 {
 310         struct list_head *node, *next;
 311         struct gameport_event *e;
 312         unsigned long flags;
 313
 314         spin_lock_irqsave(&gameport_event_lock, flags);
 315
 316         list_for_each_safe(node, next, &gameport_event_list) {
 317                 e = list_entry(node, struct gameport_event, node);
 318                 if (event->object == e->object) {
 319                         /*
 320                          * If this event is of different type we should not
 321                          * look further - we only suppress duplicate events
 322                          * that were sent back-to-back.
 323                          */
 324                         if (event->type != e->type)
 325                                 break;
 326
 327                         list_del_init(node);
 328                         gameport_free_event(e);
 329                 }
 330         }
 331
 332         spin_unlock_irqrestore(&gameport_event_lock, flags);
 333 }
 334
 335 static struct gameport_event *gameport_get_event(void)
 336 {
 337         struct gameport_event *event;
 338         struct list_head *node;
 339         unsigned long flags;
 340
 341         spin_lock_irqsave(&gameport_event_lock, flags);
 342
 343         if (list_empty(&gameport_event_list)) {
 344                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 345                 return NULL;
 346         }
 347
 348         node = gameport_event_list.next;
 349         event = list_entry(node, struct gameport_event, node);
 350         list_del_init(node);
 351
 352         spin_unlock_irqrestore(&gameport_event_lock, flags);
 353
 354         return event;
 355 }
 356
 357 static void gameport_handle_event(void)
 358 {
 359         struct gameport_event *event;
 360
 361         mutex_lock(&gameport_mutex);
 362
 363         /*
 364          * Note that we handle only one event here to give swsusp
 365          * a chance to freeze kgameportd thread. Gameport events
 366          * should be pretty rare so we are not concerned about
 367          * taking performance hit.
 368          */
 369         if ((event = gameport_get_event())) {
 370
 371                 switch (event->type) {
 372                         case GAMEPORT_REGISTER_PORT:
 373                                 gameport_add_port(event->object);
 374                                 break;
 375
 376                         case GAMEPORT_ATTACH_DRIVER:
 377                                 gameport_attach_driver(event->object);
 378                                 break;
 379
 380                         default:
 381                                 break;
 382                 }
 383
 384                 gameport_remove_duplicate_events(event);
 385                 gameport_free_event(event);
 386         }
 387
 388         mutex_unlock(&gameport_mutex);
 389 }
 390
 391 /*
 392  * Remove all events that have been submitted for a given object,
 393  * be it a gameport port or a driver.
 394  */
 395 static void gameport_remove_pending_events(void *object)
 396 {
 397         struct list_head *node, *next;
 398         struct gameport_event *event;
 399         unsigned long flags;
 400
 401         spin_lock_irqsave(&gameport_event_lock, flags);
 402
 403         list_for_each_safe(node, next, &gameport_event_list) {
 404                 event = list_entry(node, struct gameport_event, node);
 405                 if (event->object == object) {
 406                         list_del_init(node);
 407                         gameport_free_event(event);
 408                 }
 409         }
 410
 411         spin_unlock_irqrestore(&gameport_event_lock, flags);
 412 }
 413
 414 /*
 415  * Destroy child gameport port (if any) that has not been fully registered yet.
 416  *
 417  * Note that we rely on the fact that port can have only one child and therefore
 418  * only one child registration request can be pending. Additionally, children
 419  * are registered by driver's connect() handler so there can't be a grandchild
 420  * pending registration together with a child.
 421  */
 422 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 423 {
 424         struct gameport_event *event;
 425         struct gameport *gameport, *child = NULL;
 426         unsigned long flags;
 427
 428         spin_lock_irqsave(&gameport_event_lock, flags);
 429
 430         list_for_each_entry(event, &gameport_event_list, node) {
 431                 if (event->type == GAMEPORT_REGISTER_PORT) {
 432                         gameport = event->object;
 433                         if (gameport->parent == parent) {
 434                                 child = gameport;
 435                                 break;
 436                         }
 437                 }
 438         }
 439
 440         spin_unlock_irqrestore(&gameport_event_lock, flags);
 441         return child;
 442 }
 443
 444 static int gameport_thread(void *nothing)
 445 {
 446         set_freezable();
 447         do {
 448                 gameport_handle_event();
 449                 wait_event_freezable(gameport_wait,
 450                         kthread_should_stop() || !list_empty(&gameport_event_list));
 451         } while (!kthread_should_stop());
 452
 453         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 454         return 0;
 455 }
 456
 457
 458 /*
 459  * Gameport port operations
 460  */
 461
 462 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 463 {
 464         struct gameport *gameport = to_gameport_port(dev);
 465         return sprintf(buf, "%s\n", gameport->name);
 466 }
 467
 468 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 469 {
 470         struct gameport *gameport = to_gameport_port(dev);
 471         struct device_driver *drv;
 472         int error;
 473
 474         error = mutex_lock_interruptible(&gameport_mutex);
 475         if (error)
 476                 return error;
 477
 478         if (!strncmp(buf, "none", count)) {
 479                 gameport_disconnect_port(gameport);
 480         } else if (!strncmp(buf, "reconnect", count)) {
 481                 gameport_reconnect_port(gameport);
 482         } else if (!strncmp(buf, "rescan", count)) {
 483                 gameport_disconnect_port(gameport);
 484                 gameport_find_driver(gameport);
 485         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 486                 gameport_disconnect_port(gameport);
 487                 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
 488                 put_driver(drv);
 489         } else {
 490                 error = -EINVAL;
 491         }
 492
 493         mutex_unlock(&gameport_mutex);
 494
 495         return error ? error : count;
 496 }
 497
 498 static struct device_attribute gameport_device_attrs[] = {
 499         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 500         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 501         __ATTR_NULL
 502 };
 503
 504 static void gameport_release_port(struct device *dev)
 505 {
 506         struct gameport *gameport = to_gameport_port(dev);
 507
 508         kfree(gameport);
 509         module_put(THIS_MODULE);
 510 }
 511
 512 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 513 {
 514         va_list args;
 515
 516         va_start(args, fmt);
 517         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 518         va_end(args);
 519 }
 520
 521 /*
 522  * Prepare gameport port for registration.
 523  */
 524 static void gameport_init_port(struct gameport *gameport)
 525 {
 526         static atomic_t gameport_no = ATOMIC_INIT(0);
 527
 528         __module_get(THIS_MODULE);
 529
 530         mutex_init(&gameport->drv_mutex);
 531         device_initialize(&gameport->dev);
 532         dev_set_name(&gameport->dev, "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 533         gameport->dev.bus = &gameport_bus;
 534         gameport->dev.release = gameport_release_port;
 535         if (gameport->parent)
 536                 gameport->dev.parent = &gameport->parent->dev;
 537
 538         INIT_LIST_HEAD(&gameport->node);
 539         spin_lock_init(&gameport->timer_lock);
 540         init_timer(&gameport->poll_timer);
 541         gameport->poll_timer.function = gameport_run_poll_handler;
 542         gameport->poll_timer.data = (unsigned long)gameport;
 543 }
 544
 545 /*
 546  * Complete gameport port registration.
 547  * Driver core will attempt to find appropriate driver for the port.
 548  */
 549 static void gameport_add_port(struct gameport *gameport)
 550 {
 551         int error;
 552
 553         if (gameport->parent)
 554                 gameport->parent->child = gameport;
 555
 556         gameport->speed = gameport_measure_speed(gameport);
 557
 558         list_add_tail(&gameport->node, &gameport_list);
 559
 560         if (gameport->io)
 561                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 562                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 563         else
 564                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 565                         gameport->name, gameport->phys, gameport->speed);
 566
 567         error = device_add(&gameport->dev);
 568         if (error)
 569                 printk(KERN_ERR
 570                         "gameport: device_add() failed for %s (%s), error: %d\n",
 571                         gameport->phys, gameport->name, error);
 572         else
 573                 gameport->registered = 1;
 574 }
 575
 576 /*
 577  * gameport_destroy_port() completes deregistration process and removes
 578  * port from the system
 579  */
 580 static void gameport_destroy_port(struct gameport *gameport)
 581 {
 582         struct gameport *child;
 583
 584         child = gameport_get_pending_child(gameport);
 585         if (child) {
 586                 gameport_remove_pending_events(child);
 587                 put_device(&child->dev);
 588         }
 589
 590         if (gameport->parent) {
 591                 gameport->parent->child = NULL;
 592                 gameport->parent = NULL;
 593         }
 594
 595         if (gameport->registered) {
 596                 device_del(&gameport->dev);
 597                 gameport->registered = 0;
 598         }
 599
 600         list_del_init(&gameport->node);
 601
 602         gameport_remove_pending_events(gameport);
 603         put_device(&gameport->dev);
 604 }
 605
 606 /*
 607  * Reconnect gameport port and all its children (re-initialize attached devices)
 608  */
 609 static void gameport_reconnect_port(struct gameport *gameport)
 610 {
 611         do {
 612                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 613                         gameport_disconnect_port(gameport);
 614                         gameport_find_driver(gameport);
 615                         /* Ok, old children are now gone, we are done */
 616                         break;
 617                 }
 618                 gameport = gameport->child;
 619         } while (gameport);
 620 }
 621
 622 /*
 623  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 624  * all child ports are unbound and destroyed.
 625  */
 626 static void gameport_disconnect_port(struct gameport *gameport)
 627 {
 628         struct gameport *s, *parent;
 629
 630         if (gameport->child) {
 631                 /*
 632                  * Children ports should be disconnected and destroyed
 633                  * first, staring with the leaf one, since we don't want
 634                  * to do recursion
 635                  */
 636                 for (s = gameport; s->child; s = s->child)
 637                         /* empty */;
 638
 639                 do {
 640                         parent = s->parent;
 641
 642                         device_release_driver(&s->dev);
 643                         gameport_destroy_port(s);
 644                 } while ((s = parent) != gameport);
 645         }
 646
 647         /*
 648          * Ok, no children left, now disconnect this port
 649          */
 650         device_release_driver(&gameport->dev);
 651 }
 652
 653 /*
 654  * Submits register request to kgameportd for subsequent execution.
 655  * Note that port registration is always asynchronous.
 656  */
 657 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 658 {
 659         gameport_init_port(gameport);
 660         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 661 }
 662
 663 /*
 664  * Synchronously unregisters gameport port.
 665  */
 666 void gameport_unregister_port(struct gameport *gameport)
 667 {
 668         mutex_lock(&gameport_mutex);
 669         gameport_disconnect_port(gameport);
 670         gameport_destroy_port(gameport);
 671         mutex_unlock(&gameport_mutex);
 672 }
 673
 674
 675 /*
 676  * Gameport driver operations
 677  */
 678
 679 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 680 {
 681         struct gameport_driver *driver = to_gameport_driver(drv);
 682         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 683 }
 684
 685 static struct driver_attribute gameport_driver_attrs[] = {
 686         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 687         __ATTR_NULL
 688 };
 689
 690 static int gameport_driver_probe(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->connect(gameport, drv);
 696         return gameport->drv ? 0 : -ENODEV;
 697 }
 698
 699 static int gameport_driver_remove(struct device *dev)
 700 {
 701         struct gameport *gameport = to_gameport_port(dev);
 702         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 703
 704         drv->disconnect(gameport);
 705         return 0;
 706 }
 707
 708 static void gameport_attach_driver(struct gameport_driver *drv)
 709 {
 710         int error;
 711
 712         error = driver_attach(&drv->driver);
 713         if (error)
 714                 printk(KERN_ERR
 715                         "gameport: driver_attach() failed for %s, error: %d\n",
 716                         drv->driver.name, error);
 717 }
 718
 719 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
 720                                 const char *mod_name)
 721 {
 722         int error;
 723
 724         drv->driver.bus = &gameport_bus;
 725         drv->driver.owner = owner;
 726         drv->driver.mod_name = mod_name;
 727
 728         /*
 729          * Temporarily disable automatic binding because probing
 730          * takes long time and we are better off doing it in kgameportd
 731          */
 732         drv->ignore = 1;
 733
 734         error = driver_register(&drv->driver);
 735         if (error) {
 736                 printk(KERN_ERR
 737                         "gameport: driver_register() failed for %s, error: %d\n",
 738                         drv->driver.name, error);
 739                 return error;
 740         }
 741
 742         /*
 743          * Reset ignore flag and let kgameportd bind the driver to free ports
 744          */
 745         drv->ignore = 0;
 746         error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
 747         if (error) {
 748                 driver_unregister(&drv->driver);
 749                 return error;
 750         }
 751
 752         return 0;
 753 }
 754
 755 void gameport_unregister_driver(struct gameport_driver *drv)
 756 {
 757         struct gameport *gameport;
 758
 759         mutex_lock(&gameport_mutex);
 760
 761         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 762         gameport_remove_pending_events(drv);
 763
 764 start_over:
 765         list_for_each_entry(gameport, &gameport_list, node) {
 766                 if (gameport->drv == drv) {
 767                         gameport_disconnect_port(gameport);
 768                         gameport_find_driver(gameport);
 769                         /* we could've deleted some ports, restart */
 770                         goto start_over;
 771                 }
 772         }
 773
 774         driver_unregister(&drv->driver);
 775
 776         mutex_unlock(&gameport_mutex);
 777 }
 778
 779 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 780 {
 781         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 782
 783         return !gameport_drv->ignore;
 784 }
 785
 786 static struct bus_type gameport_bus = {
 787         .name           = "gameport",
 788         .dev_attrs      = gameport_device_attrs,
 789         .drv_attrs      = gameport_driver_attrs,
 790         .match          = gameport_bus_match,
 791         .probe          = gameport_driver_probe,
 792         .remove         = gameport_driver_remove,
 793 };
 794
 795 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 796 {
 797         mutex_lock(&gameport->drv_mutex);
 798         gameport->drv = drv;
 799         mutex_unlock(&gameport->drv_mutex);
 800 }
 801
 802 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 803 {
 804         if (gameport->open) {
 805                 if (gameport->open(gameport, mode)) {
 806                         return -1;
 807                 }
 808         } else {
 809                 if (mode != GAMEPORT_MODE_RAW)
 810                         return -1;
 811         }
 812
 813         gameport_set_drv(gameport, drv);
 814         return 0;
 815 }
 816
 817 void gameport_close(struct gameport *gameport)
 818 {
 819         del_timer_sync(&gameport->poll_timer);
 820         gameport->poll_handler = NULL;
 821         gameport->poll_interval = 0;
 822         gameport_set_drv(gameport, NULL);
 823         if (gameport->close)
 824                 gameport->close(gameport);
 825 }
 826
 827 static int __init gameport_init(void)
 828 {
 829         int error;
 830
 831         error = bus_register(&gameport_bus);
 832         if (error) {
 833                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 834                 return error;
 835         }
 836
 837         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 838         if (IS_ERR(gameport_task)) {
 839                 bus_unregister(&gameport_bus);
 840                 error = PTR_ERR(gameport_task);
 841                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 842                 return error;
 843         }
 844
 845         return 0;
 846 }
 847
 848 static void __exit gameport_exit(void)
 849 {
 850         bus_unregister(&gameport_bus);
 851         kthread_stop(gameport_task);
 852 }
 853
 854 subsys_initcall(gameport_init);
 855 module_exit(gameport_exit);