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_port(struct gameport *gameport);
  54 static void gameport_attach_driver(struct gameport_driver *drv);
  55 static void gameport_reconnect_port(struct gameport *gameport);
  56 static void gameport_disconnect_port(struct gameport *gameport);
  57
  58 #if defined(__i386__)
  59
  60 #include <asm/i8253.h>
  61
  62 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  63 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  64
  65 static unsigned int get_time_pit(void)
  66 {
  67         unsigned long flags;
  68         unsigned int count;
  69
  70         spin_lock_irqsave(&i8253_lock, flags);
  71         outb_p(0x00, 0x43);
  72         count = inb_p(0x40);
  73         count |= inb_p(0x40) << 8;
  74         spin_unlock_irqrestore(&i8253_lock, flags);
  75
  76         return count;
  77 }
  78
  79 #endif
  80
  81
  82
  83 /*
  84  * gameport_measure_speed() measures the gameport i/o speed.
  85  */
  86
  87 static int gameport_measure_speed(struct gameport *gameport)
  88 {
  89 #if defined(__i386__)
  90
  91         unsigned int i, t, t1, t2, t3, tx;
  92         unsigned long flags;
  93
  94         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  95                 return 0;
  96
  97         tx = 1 << 30;
  98
  99         for(i = 0; i < 50; i++) {
 100                 local_irq_save(flags);
 101                 GET_TIME(t1);
 102                 for (t = 0; t < 50; t++) gameport_read(gameport);
 103                 GET_TIME(t2);
 104                 GET_TIME(t3);
 105                 local_irq_restore(flags);
 106                 udelay(i * 10);
 107                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 108         }
 109
 110         gameport_close(gameport);
 111         return 59659 / (tx < 1 ? 1 : tx);
 112
 113 #elif defined (__x86_64__)
 114
 115         unsigned int i, t;
 116         unsigned long tx, t1, t2, flags;
 117
 118         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 119                 return 0;
 120
 121         tx = 1 << 30;
 122
 123         for(i = 0; i < 50; i++) {
 124                 local_irq_save(flags);
 125                 rdtscl(t1);
 126                 for (t = 0; t < 50; t++) gameport_read(gameport);
 127                 rdtscl(t2);
 128                 local_irq_restore(flags);
 129                 udelay(i * 10);
 130                 if (t2 - t1 < tx) tx = t2 - t1;
 131         }
 132
 133         gameport_close(gameport);
 134         return (cpu_data(raw_smp_processor_id()).loops_per_jiffy *
 135                 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 136
 137 #else
 138
 139         unsigned int j, t = 0;
 140
 141         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 142                 return 0;
 143
 144         j = jiffies; while (j == jiffies);
 145         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 146
 147         gameport_close(gameport);
 148         return t * HZ / 1000;
 149
 150 #endif
 151 }
 152
 153 void gameport_start_polling(struct gameport *gameport)
 154 {
 155         spin_lock(&gameport->timer_lock);
 156
 157         if (!gameport->poll_cnt++) {
 158                 BUG_ON(!gameport->poll_handler);
 159                 BUG_ON(!gameport->poll_interval);
 160                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 161         }
 162
 163         spin_unlock(&gameport->timer_lock);
 164 }
 165
 166 void gameport_stop_polling(struct gameport *gameport)
 167 {
 168         spin_lock(&gameport->timer_lock);
 169
 170         if (!--gameport->poll_cnt)
 171                 del_timer(&gameport->poll_timer);
 172
 173         spin_unlock(&gameport->timer_lock);
 174 }
 175
 176 static void gameport_run_poll_handler(unsigned long d)
 177 {
 178         struct gameport *gameport = (struct gameport *)d;
 179
 180         gameport->poll_handler(gameport);
 181         if (gameport->poll_cnt)
 182                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 183 }
 184
 185 /*
 186  * Basic gameport -> driver core mappings
 187  */
 188
 189 static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 190 {
 191         int error;
 192
 193         gameport->dev.driver = &drv->driver;
 194         if (drv->connect(gameport, drv)) {
 195                 gameport->dev.driver = NULL;
 196                 return -ENODEV;
 197         }
 198
 199         error = device_bind_driver(&gameport->dev);
 200         if (error) {
 201                 printk(KERN_WARNING
 202                         "gameport: device_bind_driver() failed "
 203                         "for %s (%s) and %s, error: %d\n",
 204                         gameport->phys, gameport->name,
 205                         drv->description, error);
 206                 drv->disconnect(gameport);
 207                 gameport->dev.driver = NULL;
 208                 return error;
 209         }
 210
 211         return 0;
 212 }
 213
 214 static void gameport_find_driver(struct gameport *gameport)
 215 {
 216         int error;
 217
 218         error = device_attach(&gameport->dev);
 219         if (error < 0)
 220                 printk(KERN_WARNING
 221                         "gameport: device_attach() failed for %s (%s), error: %d\n",
 222                         gameport->phys, gameport->name, error);
 223 }
 224
 225
 226 /*
 227  * Gameport event processing.
 228  */
 229
 230 enum gameport_event_type {
 231         GAMEPORT_REGISTER_PORT,
 232         GAMEPORT_ATTACH_DRIVER,
 233 };
 234
 235 struct gameport_event {
 236         enum gameport_event_type type;
 237         void *object;
 238         struct module *owner;
 239         struct list_head node;
 240 };
 241
 242 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 243 static LIST_HEAD(gameport_event_list);
 244 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 245 static struct task_struct *gameport_task;
 246
 247 static int gameport_queue_event(void *object, struct module *owner,
 248                                 enum gameport_event_type event_type)
 249 {
 250         unsigned long flags;
 251         struct gameport_event *event;
 252         int retval = 0;
 253
 254         spin_lock_irqsave(&gameport_event_lock, flags);
 255
 256         /*
 257          * Scan event list for the other events for the same gameport port,
 258          * starting with the most recent one. If event is the same we
 259          * do not need add new one. If event is of different type we
 260          * need to add this event and should not look further because
 261          * we need to preseve sequence of distinct events.
 262          */
 263         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 264                 if (event->object == object) {
 265                         if (event->type == event_type)
 266                                 goto out;
 267                         break;
 268                 }
 269         }
 270
 271         event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
 272         if (!event) {
 273                 printk(KERN_ERR
 274                         "gameport: Not enough memory to queue event %d\n",
 275                         event_type);
 276                 retval = -ENOMEM;
 277                 goto out;
 278         }
 279
 280         if (!try_module_get(owner)) {
 281                 printk(KERN_WARNING
 282                         "gameport: Can't get module reference, dropping event %d\n",
 283                         event_type);
 284                 kfree(event);
 285                 retval = -EINVAL;
 286                 goto out;
 287         }
 288
 289         event->type = event_type;
 290         event->object = object;
 291         event->owner = owner;
 292
 293         list_add_tail(&event->node, &gameport_event_list);
 294         wake_up(&gameport_wait);
 295
 296 out:
 297         spin_unlock_irqrestore(&gameport_event_lock, flags);
 298         return retval;
 299 }
 300
 301 static void gameport_free_event(struct gameport_event *event)
 302 {
 303         module_put(event->owner);
 304         kfree(event);
 305 }
 306
 307 static void gameport_remove_duplicate_events(struct gameport_event *event)
 308 {
 309         struct list_head *node, *next;
 310         struct gameport_event *e;
 311         unsigned long flags;
 312
 313         spin_lock_irqsave(&gameport_event_lock, flags);
 314
 315         list_for_each_safe(node, next, &gameport_event_list) {
 316                 e = list_entry(node, struct gameport_event, node);
 317                 if (event->object == e->object) {
 318                         /*
 319                          * If this event is of different type we should not
 320                          * look further - we only suppress duplicate events
 321                          * that were sent back-to-back.
 322                          */
 323                         if (event->type != e->type)
 324                                 break;
 325
 326                         list_del_init(node);
 327                         gameport_free_event(e);
 328                 }
 329         }
 330
 331         spin_unlock_irqrestore(&gameport_event_lock, flags);
 332 }
 333
 334 static struct gameport_event *gameport_get_event(void)
 335 {
 336         struct gameport_event *event;
 337         struct list_head *node;
 338         unsigned long flags;
 339
 340         spin_lock_irqsave(&gameport_event_lock, flags);
 341
 342         if (list_empty(&gameport_event_list)) {
 343                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 344                 return NULL;
 345         }
 346
 347         node = gameport_event_list.next;
 348         event = list_entry(node, struct gameport_event, node);
 349         list_del_init(node);
 350
 351         spin_unlock_irqrestore(&gameport_event_lock, flags);
 352
 353         return event;
 354 }
 355
 356 static void gameport_handle_event(void)
 357 {
 358         struct gameport_event *event;
 359
 360         mutex_lock(&gameport_mutex);
 361
 362         /*
 363          * Note that we handle only one event here to give swsusp
 364          * a chance to freeze kgameportd thread. Gameport events
 365          * should be pretty rare so we are not concerned about
 366          * taking performance hit.
 367          */
 368         if ((event = gameport_get_event())) {
 369
 370                 switch (event->type) {
 371                         case GAMEPORT_REGISTER_PORT:
 372                                 gameport_add_port(event->object);
 373                                 break;
 374
 375                         case GAMEPORT_ATTACH_DRIVER:
 376                                 gameport_attach_driver(event->object);
 377                                 break;
 378
 379                         default:
 380                                 break;
 381                 }
 382
 383                 gameport_remove_duplicate_events(event);
 384                 gameport_free_event(event);
 385         }
 386
 387         mutex_unlock(&gameport_mutex);
 388 }
 389
 390 /*
 391  * Remove all events that have been submitted for a given object,
 392  * be it a gameport port or a driver.
 393  */
 394 static void gameport_remove_pending_events(void *object)
 395 {
 396         struct list_head *node, *next;
 397         struct gameport_event *event;
 398         unsigned long flags;
 399
 400         spin_lock_irqsave(&gameport_event_lock, flags);
 401
 402         list_for_each_safe(node, next, &gameport_event_list) {
 403                 event = list_entry(node, struct gameport_event, node);
 404                 if (event->object == object) {
 405                         list_del_init(node);
 406                         gameport_free_event(event);
 407                 }
 408         }
 409
 410         spin_unlock_irqrestore(&gameport_event_lock, flags);
 411 }
 412
 413 /*
 414  * Destroy child gameport port (if any) that has not been fully registered yet.
 415  *
 416  * Note that we rely on the fact that port can have only one child and therefore
 417  * only one child registration request can be pending. Additionally, children
 418  * are registered by driver's connect() handler so there can't be a grandchild
 419  * pending registration together with a child.
 420  */
 421 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 422 {
 423         struct gameport_event *event;
 424         struct gameport *gameport, *child = NULL;
 425         unsigned long flags;
 426
 427         spin_lock_irqsave(&gameport_event_lock, flags);
 428
 429         list_for_each_entry(event, &gameport_event_list, node) {
 430                 if (event->type == GAMEPORT_REGISTER_PORT) {
 431                         gameport = event->object;
 432                         if (gameport->parent == parent) {
 433                                 child = gameport;
 434                                 break;
 435                         }
 436                 }
 437         }
 438
 439         spin_unlock_irqrestore(&gameport_event_lock, flags);
 440         return child;
 441 }
 442
 443 static int gameport_thread(void *nothing)
 444 {
 445         set_freezable();
 446         do {
 447                 gameport_handle_event();
 448                 wait_event_freezable(gameport_wait,
 449                         kthread_should_stop() || !list_empty(&gameport_event_list));
 450         } while (!kthread_should_stop());
 451
 452         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 453         return 0;
 454 }
 455
 456
 457 /*
 458  * Gameport port operations
 459  */
 460
 461 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 462 {
 463         struct gameport *gameport = to_gameport_port(dev);
 464         return sprintf(buf, "%s\n", gameport->name);
 465 }
 466
 467 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 468 {
 469         struct gameport *gameport = to_gameport_port(dev);
 470         struct device_driver *drv;
 471         int error;
 472
 473         error = mutex_lock_interruptible(&gameport_mutex);
 474         if (error)
 475                 return error;
 476
 477         if (!strncmp(buf, "none", count)) {
 478                 gameport_disconnect_port(gameport);
 479         } else if (!strncmp(buf, "reconnect", count)) {
 480                 gameport_reconnect_port(gameport);
 481         } else if (!strncmp(buf, "rescan", count)) {
 482                 gameport_disconnect_port(gameport);
 483                 gameport_find_driver(gameport);
 484         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 485                 gameport_disconnect_port(gameport);
 486                 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
 487                 put_driver(drv);
 488         } else {
 489                 error = -EINVAL;
 490         }
 491
 492         mutex_unlock(&gameport_mutex);
 493
 494         return error ? error : count;
 495 }
 496
 497 static struct device_attribute gameport_device_attrs[] = {
 498         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 499         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 500         __ATTR_NULL
 501 };
 502
 503 static void gameport_release_port(struct device *dev)
 504 {
 505         struct gameport *gameport = to_gameport_port(dev);
 506
 507         kfree(gameport);
 508         module_put(THIS_MODULE);
 509 }
 510
 511 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 512 {
 513         va_list args;
 514
 515         va_start(args, fmt);
 516         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 517         va_end(args);
 518 }
 519
 520 /*
 521  * Prepare gameport port for registration.
 522  */
 523 static void gameport_init_port(struct gameport *gameport)
 524 {
 525         static atomic_t gameport_no = ATOMIC_INIT(0);
 526
 527         __module_get(THIS_MODULE);
 528
 529         mutex_init(&gameport->drv_mutex);
 530         device_initialize(&gameport->dev);
 531         dev_set_name(&gameport->dev, "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 532         gameport->dev.bus = &gameport_bus;
 533         gameport->dev.release = gameport_release_port;
 534         if (gameport->parent)
 535                 gameport->dev.parent = &gameport->parent->dev;
 536
 537         INIT_LIST_HEAD(&gameport->node);
 538         spin_lock_init(&gameport->timer_lock);
 539         init_timer(&gameport->poll_timer);
 540         gameport->poll_timer.function = gameport_run_poll_handler;
 541         gameport->poll_timer.data = (unsigned long)gameport;
 542 }
 543
 544 /*
 545  * Complete gameport port registration.
 546  * Driver core will attempt to find appropriate driver for the port.
 547  */
 548 static void gameport_add_port(struct gameport *gameport)
 549 {
 550         int error;
 551
 552         if (gameport->parent)
 553                 gameport->parent->child = gameport;
 554
 555         gameport->speed = gameport_measure_speed(gameport);
 556
 557         list_add_tail(&gameport->node, &gameport_list);
 558
 559         if (gameport->io)
 560                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 561                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 562         else
 563                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 564                         gameport->name, gameport->phys, gameport->speed);
 565
 566         error = device_add(&gameport->dev);
 567         if (error)
 568                 printk(KERN_ERR
 569                         "gameport: device_add() failed for %s (%s), error: %d\n",
 570                         gameport->phys, gameport->name, error);
 571         else
 572                 gameport->registered = 1;
 573 }
 574
 575 /*
 576  * gameport_destroy_port() completes deregistration process and removes
 577  * port from the system
 578  */
 579 static void gameport_destroy_port(struct gameport *gameport)
 580 {
 581         struct gameport *child;
 582
 583         child = gameport_get_pending_child(gameport);
 584         if (child) {
 585                 gameport_remove_pending_events(child);
 586                 put_device(&child->dev);
 587         }
 588
 589         if (gameport->parent) {
 590                 gameport->parent->child = NULL;
 591                 gameport->parent = NULL;
 592         }
 593
 594         if (gameport->registered) {
 595                 device_del(&gameport->dev);
 596                 gameport->registered = 0;
 597         }
 598
 599         list_del_init(&gameport->node);
 600
 601         gameport_remove_pending_events(gameport);
 602         put_device(&gameport->dev);
 603 }
 604
 605 /*
 606  * Reconnect gameport port and all its children (re-initialize attached devices)
 607  */
 608 static void gameport_reconnect_port(struct gameport *gameport)
 609 {
 610         do {
 611                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 612                         gameport_disconnect_port(gameport);
 613                         gameport_find_driver(gameport);
 614                         /* Ok, old children are now gone, we are done */
 615                         break;
 616                 }
 617                 gameport = gameport->child;
 618         } while (gameport);
 619 }
 620
 621 /*
 622  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 623  * all child ports are unbound and destroyed.
 624  */
 625 static void gameport_disconnect_port(struct gameport *gameport)
 626 {
 627         struct gameport *s, *parent;
 628
 629         if (gameport->child) {
 630                 /*
 631                  * Children ports should be disconnected and destroyed
 632                  * first, staring with the leaf one, since we don't want
 633                  * to do recursion
 634                  */
 635                 for (s = gameport; s->child; s = s->child)
 636                         /* empty */;
 637
 638                 do {
 639                         parent = s->parent;
 640
 641                         device_release_driver(&s->dev);
 642                         gameport_destroy_port(s);
 643                 } while ((s = parent) != gameport);
 644         }
 645
 646         /*
 647          * Ok, no children left, now disconnect this port
 648          */
 649         device_release_driver(&gameport->dev);
 650 }
 651
 652 /*
 653  * Submits register request to kgameportd for subsequent execution.
 654  * Note that port registration is always asynchronous.
 655  */
 656 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 657 {
 658         gameport_init_port(gameport);
 659         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 660 }
 661
 662 /*
 663  * Synchronously unregisters gameport port.
 664  */
 665 void gameport_unregister_port(struct gameport *gameport)
 666 {
 667         mutex_lock(&gameport_mutex);
 668         gameport_disconnect_port(gameport);
 669         gameport_destroy_port(gameport);
 670         mutex_unlock(&gameport_mutex);
 671 }
 672
 673
 674 /*
 675  * Gameport driver operations
 676  */
 677
 678 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 679 {
 680         struct gameport_driver *driver = to_gameport_driver(drv);
 681         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 682 }
 683
 684 static struct driver_attribute gameport_driver_attrs[] = {
 685         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 686         __ATTR_NULL
 687 };
 688
 689 static int gameport_driver_probe(struct device *dev)
 690 {
 691         struct gameport *gameport = to_gameport_port(dev);
 692         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 693
 694         drv->connect(gameport, drv);
 695         return gameport->drv ? 0 : -ENODEV;
 696 }
 697
 698 static int gameport_driver_remove(struct device *dev)
 699 {
 700         struct gameport *gameport = to_gameport_port(dev);
 701         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 702
 703         drv->disconnect(gameport);
 704         return 0;
 705 }
 706
 707 static void gameport_attach_driver(struct gameport_driver *drv)
 708 {
 709         int error;
 710
 711         error = driver_attach(&drv->driver);
 712         if (error)
 713                 printk(KERN_ERR
 714                         "gameport: driver_attach() failed for %s, error: %d\n",
 715                         drv->driver.name, error);
 716 }
 717
 718 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
 719                                 const char *mod_name)
 720 {
 721         int error;
 722
 723         drv->driver.bus = &gameport_bus;
 724         drv->driver.owner = owner;
 725         drv->driver.mod_name = mod_name;
 726
 727         /*
 728          * Temporarily disable automatic binding because probing
 729          * takes long time and we are better off doing it in kgameportd
 730          */
 731         drv->ignore = 1;
 732
 733         error = driver_register(&drv->driver);
 734         if (error) {
 735                 printk(KERN_ERR
 736                         "gameport: driver_register() failed for %s, error: %d\n",
 737                         drv->driver.name, error);
 738                 return error;
 739         }
 740
 741         /*
 742          * Reset ignore flag and let kgameportd bind the driver to free ports
 743          */
 744         drv->ignore = 0;
 745         error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
 746         if (error) {
 747                 driver_unregister(&drv->driver);
 748                 return error;
 749         }
 750
 751         return 0;
 752 }
 753
 754 void gameport_unregister_driver(struct gameport_driver *drv)
 755 {
 756         struct gameport *gameport;
 757
 758         mutex_lock(&gameport_mutex);
 759
 760         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 761         gameport_remove_pending_events(drv);
 762
 763 start_over:
 764         list_for_each_entry(gameport, &gameport_list, node) {
 765                 if (gameport->drv == drv) {
 766                         gameport_disconnect_port(gameport);
 767                         gameport_find_driver(gameport);
 768                         /* we could've deleted some ports, restart */
 769                         goto start_over;
 770                 }
 771         }
 772
 773         driver_unregister(&drv->driver);
 774
 775         mutex_unlock(&gameport_mutex);
 776 }
 777
 778 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 779 {
 780         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 781
 782         return !gameport_drv->ignore;
 783 }
 784
 785 static struct bus_type gameport_bus = {
 786         .name           = "gameport",
 787         .dev_attrs      = gameport_device_attrs,
 788         .drv_attrs      = gameport_driver_attrs,
 789         .match          = gameport_bus_match,
 790         .probe          = gameport_driver_probe,
 791         .remove         = gameport_driver_remove,
 792 };
 793
 794 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 795 {
 796         mutex_lock(&gameport->drv_mutex);
 797         gameport->drv = drv;
 798         mutex_unlock(&gameport->drv_mutex);
 799 }
 800
 801 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 802 {
 803         if (gameport->open) {
 804                 if (gameport->open(gameport, mode)) {
 805                         return -1;
 806                 }
 807         } else {
 808                 if (mode != GAMEPORT_MODE_RAW)
 809                         return -1;
 810         }
 811
 812         gameport_set_drv(gameport, drv);
 813         return 0;
 814 }
 815
 816 void gameport_close(struct gameport *gameport)
 817 {
 818         del_timer_sync(&gameport->poll_timer);
 819         gameport->poll_handler = NULL;
 820         gameport->poll_interval = 0;
 821         gameport_set_drv(gameport, NULL);
 822         if (gameport->close)
 823                 gameport->close(gameport);
 824 }
 825
 826 static int __init gameport_init(void)
 827 {
 828         int error;
 829
 830         error = bus_register(&gameport_bus);
 831         if (error) {
 832                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 833                 return error;
 834         }
 835
 836         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 837         if (IS_ERR(gameport_task)) {
 838                 bus_unregister(&gameport_bus);
 839                 error = PTR_ERR(gameport_task);
 840                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 841                 return error;
 842         }
 843
 844         return 0;
 845 }
 846
 847 static void __exit gameport_exit(void)
 848 {
 849         bus_unregister(&gameport_bus);
 850         kthread_stop(gameport_task);
 851 }
 852
 853 subsys_initcall(gameport_init);
 854 module_exit(gameport_exit);