drivers/input/gameport/gameport.c

   1 /*
   2  * Generic gameport layer
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  * Copyright (c) 2005 Dmitry Torokhov
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  */
  13
  14 #include <linux/stddef.h>
  15 #include <linux/module.h>
  16 #include <linux/ioport.h>
  17 #include <linux/init.h>
  18 #include <linux/gameport.h>
  19 #include <linux/wait.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/kthread.h>
  24 #include <linux/sched.h>        /* HZ */
  25 #include <linux/mutex.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_rescan);
  40 EXPORT_SYMBOL(gameport_cooked_read);
  41 EXPORT_SYMBOL(gameport_set_name);
  42 EXPORT_SYMBOL(gameport_set_phys);
  43 EXPORT_SYMBOL(gameport_start_polling);
  44 EXPORT_SYMBOL(gameport_stop_polling);
  45
  46 /*
  47  * gameport_mutex protects entire gameport subsystem and is taken
  48  * every time gameport port or driver registrered or unregistered.
  49  */
  50 static DEFINE_MUTEX(gameport_mutex);
  51
  52 static LIST_HEAD(gameport_list);
  53
  54 static struct bus_type gameport_bus;
  55
  56 static void gameport_add_driver(struct gameport_driver *drv);
  57 static void gameport_add_port(struct gameport *gameport);
  58 static void gameport_destroy_port(struct gameport *gameport);
  59 static void gameport_reconnect_port(struct gameport *gameport);
  60 static void gameport_disconnect_port(struct gameport *gameport);
  61
  62 #if defined(__i386__)
  63
  64 #include <asm/i8253.h>
  65
  66 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  67 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  68
  69 static unsigned int get_time_pit(void)
  70 {
  71         unsigned long flags;
  72         unsigned int count;
  73
  74         spin_lock_irqsave(&i8253_lock, flags);
  75         outb_p(0x00, 0x43);
  76         count = inb_p(0x40);
  77         count |= inb_p(0x40) << 8;
  78         spin_unlock_irqrestore(&i8253_lock, flags);
  79
  80         return count;
  81 }
  82
  83 #endif
  84
  85
  86
  87 /*
  88  * gameport_measure_speed() measures the gameport i/o speed.
  89  */
  90
  91 static int gameport_measure_speed(struct gameport *gameport)
  92 {
  93 #if defined(__i386__)
  94
  95         unsigned int i, t, t1, t2, t3, tx;
  96         unsigned long flags;
  97
  98         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  99                 return 0;
 100
 101         tx = 1 << 30;
 102
 103         for(i = 0; i < 50; i++) {
 104                 local_irq_save(flags);
 105                 GET_TIME(t1);
 106                 for (t = 0; t < 50; t++) gameport_read(gameport);
 107                 GET_TIME(t2);
 108                 GET_TIME(t3);
 109                 local_irq_restore(flags);
 110                 udelay(i * 10);
 111                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 112         }
 113
 114         gameport_close(gameport);
 115         return 59659 / (tx < 1 ? 1 : tx);
 116
 117 #elif defined (__x86_64__)
 118
 119         unsigned int i, t;
 120         unsigned long tx, t1, t2, flags;
 121
 122         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 123                 return 0;
 124
 125         tx = 1 << 30;
 126
 127         for(i = 0; i < 50; i++) {
 128                 local_irq_save(flags);
 129                 rdtscl(t1);
 130                 for (t = 0; t < 50; t++) gameport_read(gameport);
 131                 rdtscl(t2);
 132                 local_irq_restore(flags);
 133                 udelay(i * 10);
 134                 if (t2 - t1 < tx) tx = t2 - t1;
 135         }
 136
 137         gameport_close(gameport);
 138         return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 139
 140 #else
 141
 142         unsigned int j, t = 0;
 143
 144         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 145                 return 0;
 146
 147         j = jiffies; while (j == jiffies);
 148         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 149
 150         gameport_close(gameport);
 151         return t * HZ / 1000;
 152
 153 #endif
 154 }
 155
 156 void gameport_start_polling(struct gameport *gameport)
 157 {
 158         spin_lock(&gameport->timer_lock);
 159
 160         if (!gameport->poll_cnt++) {
 161                 BUG_ON(!gameport->poll_handler);
 162                 BUG_ON(!gameport->poll_interval);
 163                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 164         }
 165
 166         spin_unlock(&gameport->timer_lock);
 167 }
 168
 169 void gameport_stop_polling(struct gameport *gameport)
 170 {
 171         spin_lock(&gameport->timer_lock);
 172
 173         if (!--gameport->poll_cnt)
 174                 del_timer(&gameport->poll_timer);
 175
 176         spin_unlock(&gameport->timer_lock);
 177 }
 178
 179 static void gameport_run_poll_handler(unsigned long d)
 180 {
 181         struct gameport *gameport = (struct gameport *)d;
 182
 183         gameport->poll_handler(gameport);
 184         if (gameport->poll_cnt)
 185                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 186 }
 187
 188 /*
 189  * Basic gameport -> driver core mappings
 190  */
 191
 192 static void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 193 {
 194         down_write(&gameport_bus.subsys.rwsem);
 195
 196         gameport->dev.driver = &drv->driver;
 197         if (drv->connect(gameport, drv)) {
 198                 gameport->dev.driver = NULL;
 199                 goto out;
 200         }
 201         device_bind_driver(&gameport->dev);
 202 out:
 203         up_write(&gameport_bus.subsys.rwsem);
 204 }
 205
 206 static void gameport_release_driver(struct gameport *gameport)
 207 {
 208         down_write(&gameport_bus.subsys.rwsem);
 209         device_release_driver(&gameport->dev);
 210         up_write(&gameport_bus.subsys.rwsem);
 211 }
 212
 213 static void gameport_find_driver(struct gameport *gameport)
 214 {
 215         int error;
 216
 217         down_write(&gameport_bus.subsys.rwsem);
 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         up_write(&gameport_bus.subsys.rwsem);
 224 }
 225
 226
 227 /*
 228  * Gameport event processing.
 229  */
 230
 231 enum gameport_event_type {
 232         GAMEPORT_RESCAN,
 233         GAMEPORT_RECONNECT,
 234         GAMEPORT_REGISTER_PORT,
 235         GAMEPORT_REGISTER_DRIVER,
 236 };
 237
 238 struct gameport_event {
 239         enum gameport_event_type type;
 240         void *object;
 241         struct module *owner;
 242         struct list_head node;
 243 };
 244
 245 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 246 static LIST_HEAD(gameport_event_list);
 247 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 248 static struct task_struct *gameport_task;
 249
 250 static void gameport_queue_event(void *object, struct module *owner,
 251                               enum gameport_event_type event_type)
 252 {
 253         unsigned long flags;
 254         struct gameport_event *event;
 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         if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
 274                 if (!try_module_get(owner)) {
 275                         printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
 276                         kfree(event);
 277                         goto out;
 278                 }
 279
 280                 event->type = event_type;
 281                 event->object = object;
 282                 event->owner = owner;
 283
 284                 list_add_tail(&event->node, &gameport_event_list);
 285                 wake_up(&gameport_wait);
 286         } else {
 287                 printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
 288         }
 289 out:
 290         spin_unlock_irqrestore(&gameport_event_lock, flags);
 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_RECONNECT:
 368                                 gameport_reconnect_port(event->object);
 369                                 break;
 370
 371                         case GAMEPORT_RESCAN:
 372                                 gameport_disconnect_port(event->object);
 373                                 gameport_find_driver(event->object);
 374                                 break;
 375
 376                         case GAMEPORT_REGISTER_DRIVER:
 377                                 gameport_add_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 gameport port.
 393  */
 394 static void gameport_remove_pending_events(struct gameport *gameport)
 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 == gameport) {
 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         do {
 446                 gameport_handle_event();
 447                 wait_event_interruptible(gameport_wait,
 448                         kthread_should_stop() || !list_empty(&gameport_event_list));
 449                 try_to_freeze();
 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 retval;
 472
 473         retval = mutex_lock_interruptible(&gameport_mutex);
 474         if (retval)
 475                 return retval;
 476
 477         retval = count;
 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                 gameport_bind_driver(gameport, to_gameport_driver(drv));
 488                 put_driver(drv);
 489         } else {
 490                 retval = -EINVAL;
 491         }
 492
 493         mutex_unlock(&gameport_mutex);
 494
 495         return retval;
 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         snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
 533                  "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 534         gameport->dev.bus = &gameport_bus;
 535         gameport->dev.release = gameport_release_port;
 536         if (gameport->parent)
 537                 gameport->dev.parent = &gameport->parent->dev;
 538
 539         INIT_LIST_HEAD(&gameport->node);
 540         spin_lock_init(&gameport->timer_lock);
 541         init_timer(&gameport->poll_timer);
 542         gameport->poll_timer.function = gameport_run_poll_handler;
 543         gameport->poll_timer.data = (unsigned long)gameport;
 544 }
 545
 546 /*
 547  * Complete gameport port registration.
 548  * Driver core will attempt to find appropriate driver for the port.
 549  */
 550 static void gameport_add_port(struct gameport *gameport)
 551 {
 552         int error;
 553
 554         if (gameport->parent)
 555                 gameport->parent->child = gameport;
 556
 557         gameport->speed = gameport_measure_speed(gameport);
 558
 559         list_add_tail(&gameport->node, &gameport_list);
 560
 561         if (gameport->io)
 562                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 563                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 564         else
 565                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 566                         gameport->name, gameport->phys, gameport->speed);
 567
 568         error = device_add(&gameport->dev);
 569         if (error)
 570                 printk(KERN_ERR
 571                         "gameport: device_add() failed for %s (%s), error: %d\n",
 572                         gameport->phys, gameport->name, error);
 573         else
 574                 gameport->registered = 1;
 575 }
 576
 577 /*
 578  * gameport_destroy_port() completes deregistration process and removes
 579  * port from the system
 580  */
 581 static void gameport_destroy_port(struct gameport *gameport)
 582 {
 583         struct gameport *child;
 584
 585         child = gameport_get_pending_child(gameport);
 586         if (child) {
 587                 gameport_remove_pending_events(child);
 588                 put_device(&child->dev);
 589         }
 590
 591         if (gameport->parent) {
 592                 gameport->parent->child = NULL;
 593                 gameport->parent = NULL;
 594         }
 595
 596         if (gameport->registered) {
 597                 device_del(&gameport->dev);
 598                 gameport->registered = 0;
 599         }
 600
 601         list_del_init(&gameport->node);
 602
 603         gameport_remove_pending_events(gameport);
 604         put_device(&gameport->dev);
 605 }
 606
 607 /*
 608  * Reconnect gameport port and all its children (re-initialize attached devices)
 609  */
 610 static void gameport_reconnect_port(struct gameport *gameport)
 611 {
 612         do {
 613                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 614                         gameport_disconnect_port(gameport);
 615                         gameport_find_driver(gameport);
 616                         /* Ok, old children are now gone, we are done */
 617                         break;
 618                 }
 619                 gameport = gameport->child;
 620         } while (gameport);
 621 }
 622
 623 /*
 624  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 625  * all child ports are unbound and destroyed.
 626  */
 627 static void gameport_disconnect_port(struct gameport *gameport)
 628 {
 629         struct gameport *s, *parent;
 630
 631         if (gameport->child) {
 632                 /*
 633                  * Children ports should be disconnected and destroyed
 634                  * first, staring with the leaf one, since we don't want
 635                  * to do recursion
 636                  */
 637                 for (s = gameport; s->child; s = s->child)
 638                         /* empty */;
 639
 640                 do {
 641                         parent = s->parent;
 642
 643                         gameport_release_driver(s);
 644                         gameport_destroy_port(s);
 645                 } while ((s = parent) != gameport);
 646         }
 647
 648         /*
 649          * Ok, no children left, now disconnect this port
 650          */
 651         gameport_release_driver(gameport);
 652 }
 653
 654 void gameport_rescan(struct gameport *gameport)
 655 {
 656         gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
 657 }
 658
 659 void gameport_reconnect(struct gameport *gameport)
 660 {
 661         gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
 662 }
 663
 664 /*
 665  * Submits register request to kgameportd for subsequent execution.
 666  * Note that port registration is always asynchronous.
 667  */
 668 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 669 {
 670         gameport_init_port(gameport);
 671         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 672 }
 673
 674 /*
 675  * Synchronously unregisters gameport port.
 676  */
 677 void gameport_unregister_port(struct gameport *gameport)
 678 {
 679         mutex_lock(&gameport_mutex);
 680         gameport_disconnect_port(gameport);
 681         gameport_destroy_port(gameport);
 682         mutex_unlock(&gameport_mutex);
 683 }
 684
 685
 686 /*
 687  * Gameport driver operations
 688  */
 689
 690 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 691 {
 692         struct gameport_driver *driver = to_gameport_driver(drv);
 693         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 694 }
 695
 696 static struct driver_attribute gameport_driver_attrs[] = {
 697         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 698         __ATTR_NULL
 699 };
 700
 701 static int gameport_driver_probe(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->connect(gameport, drv);
 707         return gameport->drv ? 0 : -ENODEV;
 708 }
 709
 710 static int gameport_driver_remove(struct device *dev)
 711 {
 712         struct gameport *gameport = to_gameport_port(dev);
 713         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 714
 715         drv->disconnect(gameport);
 716         return 0;
 717 }
 718
 719 static struct bus_type gameport_bus = {
 720         .name   = "gameport",
 721         .probe  = gameport_driver_probe,
 722         .remove = gameport_driver_remove,
 723 };
 724
 725 static void gameport_add_driver(struct gameport_driver *drv)
 726 {
 727         int error;
 728
 729         error = driver_register(&drv->driver);
 730         if (error)
 731                 printk(KERN_ERR
 732                         "gameport: driver_register() failed for %s, error: %d\n",
 733                         drv->driver.name, error);
 734 }
 735
 736 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
 737 {
 738         drv->driver.bus = &gameport_bus;
 739         gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
 740 }
 741
 742 void gameport_unregister_driver(struct gameport_driver *drv)
 743 {
 744         struct gameport *gameport;
 745
 746         mutex_lock(&gameport_mutex);
 747         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 748
 749 start_over:
 750         list_for_each_entry(gameport, &gameport_list, node) {
 751                 if (gameport->drv == drv) {
 752                         gameport_disconnect_port(gameport);
 753                         gameport_find_driver(gameport);
 754                         /* we could've deleted some ports, restart */
 755                         goto start_over;
 756                 }
 757         }
 758
 759         driver_unregister(&drv->driver);
 760         mutex_unlock(&gameport_mutex);
 761 }
 762
 763 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 764 {
 765         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 766
 767         return !gameport_drv->ignore;
 768 }
 769
 770 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 771 {
 772         mutex_lock(&gameport->drv_mutex);
 773         gameport->drv = drv;
 774         mutex_unlock(&gameport->drv_mutex);
 775 }
 776
 777 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 778 {
 779
 780         if (gameport->open) {
 781                 if (gameport->open(gameport, mode)) {
 782                         return -1;
 783                 }
 784         } else {
 785                 if (mode != GAMEPORT_MODE_RAW)
 786                         return -1;
 787         }
 788
 789         gameport_set_drv(gameport, drv);
 790         return 0;
 791 }
 792
 793 void gameport_close(struct gameport *gameport)
 794 {
 795         del_timer_sync(&gameport->poll_timer);
 796         gameport->poll_handler = NULL;
 797         gameport->poll_interval = 0;
 798         gameport_set_drv(gameport, NULL);
 799         if (gameport->close)
 800                 gameport->close(gameport);
 801 }
 802
 803 static int __init gameport_init(void)
 804 {
 805         int error;
 806
 807         gameport_bus.dev_attrs = gameport_device_attrs;
 808         gameport_bus.drv_attrs = gameport_driver_attrs;
 809         gameport_bus.match = gameport_bus_match;
 810         error = bus_register(&gameport_bus);
 811         if (error) {
 812                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 813                 return error;
 814         }
 815
 816         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 817         if (IS_ERR(gameport_task)) {
 818                 bus_unregister(&gameport_bus);
 819                 error = PTR_ERR(gameport_task);
 820                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 821                 return error;
 822         }
 823
 824         return 0;
 825 }
 826
 827 static void __exit gameport_exit(void)
 828 {
 829         bus_unregister(&gameport_bus);
 830         kthread_stop(gameport_task);
 831 }
 832
 833 subsys_initcall(gameport_init);
 834 module_exit(gameport_exit);