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         int error;
 195
 196         down_write(&gameport_bus.subsys.rwsem);
 197
 198         gameport->dev.driver = &drv->driver;
 199         if (drv->connect(gameport, drv)) {
 200                 gameport->dev.driver = NULL;
 201                 goto out;
 202         }
 203
 204         error = device_bind_driver(&gameport->dev);
 205         if (error) {
 206                 printk(KERN_WARNING
 207                         "gameport: device_bind_driver() failed "
 208                         "for %s (%s) and %s, error: %d\n",
 209                         gameport->phys, gameport->name,
 210                         drv->description, error);
 211                 drv->disconnect(gameport);
 212                 gameport->dev.driver = NULL;
 213                 goto out;
 214         }
 215
 216  out:
 217         up_write(&gameport_bus.subsys.rwsem);
 218 }
 219
 220 static void gameport_release_driver(struct gameport *gameport)
 221 {
 222         down_write(&gameport_bus.subsys.rwsem);
 223         device_release_driver(&gameport->dev);
 224         up_write(&gameport_bus.subsys.rwsem);
 225 }
 226
 227 static void gameport_find_driver(struct gameport *gameport)
 228 {
 229         int error;
 230
 231         down_write(&gameport_bus.subsys.rwsem);
 232         error = device_attach(&gameport->dev);
 233         if (error < 0)
 234                 printk(KERN_WARNING
 235                         "gameport: device_attach() failed for %s (%s), error: %d\n",
 236                         gameport->phys, gameport->name, error);
 237         up_write(&gameport_bus.subsys.rwsem);
 238 }
 239
 240
 241 /*
 242  * Gameport event processing.
 243  */
 244
 245 enum gameport_event_type {
 246         GAMEPORT_RESCAN,
 247         GAMEPORT_RECONNECT,
 248         GAMEPORT_REGISTER_PORT,
 249         GAMEPORT_REGISTER_DRIVER,
 250 };
 251
 252 struct gameport_event {
 253         enum gameport_event_type type;
 254         void *object;
 255         struct module *owner;
 256         struct list_head node;
 257 };
 258
 259 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 260 static LIST_HEAD(gameport_event_list);
 261 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 262 static struct task_struct *gameport_task;
 263
 264 static void gameport_queue_event(void *object, struct module *owner,
 265                               enum gameport_event_type event_type)
 266 {
 267         unsigned long flags;
 268         struct gameport_event *event;
 269
 270         spin_lock_irqsave(&gameport_event_lock, flags);
 271
 272         /*
 273          * Scan event list for the other events for the same gameport port,
 274          * starting with the most recent one. If event is the same we
 275          * do not need add new one. If event is of different type we
 276          * need to add this event and should not look further because
 277          * we need to preseve sequence of distinct events.
 278          */
 279         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 280                 if (event->object == object) {
 281                         if (event->type == event_type)
 282                                 goto out;
 283                         break;
 284                 }
 285         }
 286
 287         if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
 288                 if (!try_module_get(owner)) {
 289                         printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
 290                         kfree(event);
 291                         goto out;
 292                 }
 293
 294                 event->type = event_type;
 295                 event->object = object;
 296                 event->owner = owner;
 297
 298                 list_add_tail(&event->node, &gameport_event_list);
 299                 wake_up(&gameport_wait);
 300         } else {
 301                 printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
 302         }
 303 out:
 304         spin_unlock_irqrestore(&gameport_event_lock, flags);
 305 }
 306
 307 static void gameport_free_event(struct gameport_event *event)
 308 {
 309         module_put(event->owner);
 310         kfree(event);
 311 }
 312
 313 static void gameport_remove_duplicate_events(struct gameport_event *event)
 314 {
 315         struct list_head *node, *next;
 316         struct gameport_event *e;
 317         unsigned long flags;
 318
 319         spin_lock_irqsave(&gameport_event_lock, flags);
 320
 321         list_for_each_safe(node, next, &gameport_event_list) {
 322                 e = list_entry(node, struct gameport_event, node);
 323                 if (event->object == e->object) {
 324                         /*
 325                          * If this event is of different type we should not
 326                          * look further - we only suppress duplicate events
 327                          * that were sent back-to-back.
 328                          */
 329                         if (event->type != e->type)
 330                                 break;
 331
 332                         list_del_init(node);
 333                         gameport_free_event(e);
 334                 }
 335         }
 336
 337         spin_unlock_irqrestore(&gameport_event_lock, flags);
 338 }
 339
 340 static struct gameport_event *gameport_get_event(void)
 341 {
 342         struct gameport_event *event;
 343         struct list_head *node;
 344         unsigned long flags;
 345
 346         spin_lock_irqsave(&gameport_event_lock, flags);
 347
 348         if (list_empty(&gameport_event_list)) {
 349                 spin_unlock_irqrestore(&gameport_event_lock, flags);
 350                 return NULL;
 351         }
 352
 353         node = gameport_event_list.next;
 354         event = list_entry(node, struct gameport_event, node);
 355         list_del_init(node);
 356
 357         spin_unlock_irqrestore(&gameport_event_lock, flags);
 358
 359         return event;
 360 }
 361
 362 static void gameport_handle_event(void)
 363 {
 364         struct gameport_event *event;
 365
 366         mutex_lock(&gameport_mutex);
 367
 368         /*
 369          * Note that we handle only one event here to give swsusp
 370          * a chance to freeze kgameportd thread. Gameport events
 371          * should be pretty rare so we are not concerned about
 372          * taking performance hit.
 373          */
 374         if ((event = gameport_get_event())) {
 375
 376                 switch (event->type) {
 377                         case GAMEPORT_REGISTER_PORT:
 378                                 gameport_add_port(event->object);
 379                                 break;
 380
 381                         case GAMEPORT_RECONNECT:
 382                                 gameport_reconnect_port(event->object);
 383                                 break;
 384
 385                         case GAMEPORT_RESCAN:
 386                                 gameport_disconnect_port(event->object);
 387                                 gameport_find_driver(event->object);
 388                                 break;
 389
 390                         case GAMEPORT_REGISTER_DRIVER:
 391                                 gameport_add_driver(event->object);
 392                                 break;
 393
 394                         default:
 395                                 break;
 396                 }
 397
 398                 gameport_remove_duplicate_events(event);
 399                 gameport_free_event(event);
 400         }
 401
 402         mutex_unlock(&gameport_mutex);
 403 }
 404
 405 /*
 406  * Remove all events that have been submitted for a given gameport port.
 407  */
 408 static void gameport_remove_pending_events(struct gameport *gameport)
 409 {
 410         struct list_head *node, *next;
 411         struct gameport_event *event;
 412         unsigned long flags;
 413
 414         spin_lock_irqsave(&gameport_event_lock, flags);
 415
 416         list_for_each_safe(node, next, &gameport_event_list) {
 417                 event = list_entry(node, struct gameport_event, node);
 418                 if (event->object == gameport) {
 419                         list_del_init(node);
 420                         gameport_free_event(event);
 421                 }
 422         }
 423
 424         spin_unlock_irqrestore(&gameport_event_lock, flags);
 425 }
 426
 427 /*
 428  * Destroy child gameport port (if any) that has not been fully registered yet.
 429  *
 430  * Note that we rely on the fact that port can have only one child and therefore
 431  * only one child registration request can be pending. Additionally, children
 432  * are registered by driver's connect() handler so there can't be a grandchild
 433  * pending registration together with a child.
 434  */
 435 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 436 {
 437         struct gameport_event *event;
 438         struct gameport *gameport, *child = NULL;
 439         unsigned long flags;
 440
 441         spin_lock_irqsave(&gameport_event_lock, flags);
 442
 443         list_for_each_entry(event, &gameport_event_list, node) {
 444                 if (event->type == GAMEPORT_REGISTER_PORT) {
 445                         gameport = event->object;
 446                         if (gameport->parent == parent) {
 447                                 child = gameport;
 448                                 break;
 449                         }
 450                 }
 451         }
 452
 453         spin_unlock_irqrestore(&gameport_event_lock, flags);
 454         return child;
 455 }
 456
 457 static int gameport_thread(void *nothing)
 458 {
 459         do {
 460                 gameport_handle_event();
 461                 wait_event_interruptible(gameport_wait,
 462                         kthread_should_stop() || !list_empty(&gameport_event_list));
 463                 try_to_freeze();
 464         } while (!kthread_should_stop());
 465
 466         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 467         return 0;
 468 }
 469
 470
 471 /*
 472  * Gameport port operations
 473  */
 474
 475 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 476 {
 477         struct gameport *gameport = to_gameport_port(dev);
 478         return sprintf(buf, "%s\n", gameport->name);
 479 }
 480
 481 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 482 {
 483         struct gameport *gameport = to_gameport_port(dev);
 484         struct device_driver *drv;
 485         int retval;
 486
 487         retval = mutex_lock_interruptible(&gameport_mutex);
 488         if (retval)
 489                 return retval;
 490
 491         retval = count;
 492         if (!strncmp(buf, "none", count)) {
 493                 gameport_disconnect_port(gameport);
 494         } else if (!strncmp(buf, "reconnect", count)) {
 495                 gameport_reconnect_port(gameport);
 496         } else if (!strncmp(buf, "rescan", count)) {
 497                 gameport_disconnect_port(gameport);
 498                 gameport_find_driver(gameport);
 499         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 500                 gameport_disconnect_port(gameport);
 501                 gameport_bind_driver(gameport, to_gameport_driver(drv));
 502                 put_driver(drv);
 503         } else {
 504                 retval = -EINVAL;
 505         }
 506
 507         mutex_unlock(&gameport_mutex);
 508
 509         return retval;
 510 }
 511
 512 static struct device_attribute gameport_device_attrs[] = {
 513         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 514         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 515         __ATTR_NULL
 516 };
 517
 518 static void gameport_release_port(struct device *dev)
 519 {
 520         struct gameport *gameport = to_gameport_port(dev);
 521
 522         kfree(gameport);
 523         module_put(THIS_MODULE);
 524 }
 525
 526 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 527 {
 528         va_list args;
 529
 530         va_start(args, fmt);
 531         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 532         va_end(args);
 533 }
 534
 535 /*
 536  * Prepare gameport port for registration.
 537  */
 538 static void gameport_init_port(struct gameport *gameport)
 539 {
 540         static atomic_t gameport_no = ATOMIC_INIT(0);
 541
 542         __module_get(THIS_MODULE);
 543
 544         mutex_init(&gameport->drv_mutex);
 545         device_initialize(&gameport->dev);
 546         snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
 547                  "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 548         gameport->dev.bus = &gameport_bus;
 549         gameport->dev.release = gameport_release_port;
 550         if (gameport->parent)
 551                 gameport->dev.parent = &gameport->parent->dev;
 552
 553         INIT_LIST_HEAD(&gameport->node);
 554         spin_lock_init(&gameport->timer_lock);
 555         init_timer(&gameport->poll_timer);
 556         gameport->poll_timer.function = gameport_run_poll_handler;
 557         gameport->poll_timer.data = (unsigned long)gameport;
 558 }
 559
 560 /*
 561  * Complete gameport port registration.
 562  * Driver core will attempt to find appropriate driver for the port.
 563  */
 564 static void gameport_add_port(struct gameport *gameport)
 565 {
 566         int error;
 567
 568         if (gameport->parent)
 569                 gameport->parent->child = gameport;
 570
 571         gameport->speed = gameport_measure_speed(gameport);
 572
 573         list_add_tail(&gameport->node, &gameport_list);
 574
 575         if (gameport->io)
 576                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 577                         gameport->name, gameport->phys, gameport->io, gameport->speed);
 578         else
 579                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 580                         gameport->name, gameport->phys, gameport->speed);
 581
 582         error = device_add(&gameport->dev);
 583         if (error)
 584                 printk(KERN_ERR
 585                         "gameport: device_add() failed for %s (%s), error: %d\n",
 586                         gameport->phys, gameport->name, error);
 587         else
 588                 gameport->registered = 1;
 589 }
 590
 591 /*
 592  * gameport_destroy_port() completes deregistration process and removes
 593  * port from the system
 594  */
 595 static void gameport_destroy_port(struct gameport *gameport)
 596 {
 597         struct gameport *child;
 598
 599         child = gameport_get_pending_child(gameport);
 600         if (child) {
 601                 gameport_remove_pending_events(child);
 602                 put_device(&child->dev);
 603         }
 604
 605         if (gameport->parent) {
 606                 gameport->parent->child = NULL;
 607                 gameport->parent = NULL;
 608         }
 609
 610         if (gameport->registered) {
 611                 device_del(&gameport->dev);
 612                 gameport->registered = 0;
 613         }
 614
 615         list_del_init(&gameport->node);
 616
 617         gameport_remove_pending_events(gameport);
 618         put_device(&gameport->dev);
 619 }
 620
 621 /*
 622  * Reconnect gameport port and all its children (re-initialize attached devices)
 623  */
 624 static void gameport_reconnect_port(struct gameport *gameport)
 625 {
 626         do {
 627                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 628                         gameport_disconnect_port(gameport);
 629                         gameport_find_driver(gameport);
 630                         /* Ok, old children are now gone, we are done */
 631                         break;
 632                 }
 633                 gameport = gameport->child;
 634         } while (gameport);
 635 }
 636
 637 /*
 638  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 639  * all child ports are unbound and destroyed.
 640  */
 641 static void gameport_disconnect_port(struct gameport *gameport)
 642 {
 643         struct gameport *s, *parent;
 644
 645         if (gameport->child) {
 646                 /*
 647                  * Children ports should be disconnected and destroyed
 648                  * first, staring with the leaf one, since we don't want
 649                  * to do recursion
 650                  */
 651                 for (s = gameport; s->child; s = s->child)
 652                         /* empty */;
 653
 654                 do {
 655                         parent = s->parent;
 656
 657                         gameport_release_driver(s);
 658                         gameport_destroy_port(s);
 659                 } while ((s = parent) != gameport);
 660         }
 661
 662         /*
 663          * Ok, no children left, now disconnect this port
 664          */
 665         gameport_release_driver(gameport);
 666 }
 667
 668 void gameport_rescan(struct gameport *gameport)
 669 {
 670         gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
 671 }
 672
 673 void gameport_reconnect(struct gameport *gameport)
 674 {
 675         gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
 676 }
 677
 678 /*
 679  * Submits register request to kgameportd for subsequent execution.
 680  * Note that port registration is always asynchronous.
 681  */
 682 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 683 {
 684         gameport_init_port(gameport);
 685         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 686 }
 687
 688 /*
 689  * Synchronously unregisters gameport port.
 690  */
 691 void gameport_unregister_port(struct gameport *gameport)
 692 {
 693         mutex_lock(&gameport_mutex);
 694         gameport_disconnect_port(gameport);
 695         gameport_destroy_port(gameport);
 696         mutex_unlock(&gameport_mutex);
 697 }
 698
 699
 700 /*
 701  * Gameport driver operations
 702  */
 703
 704 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 705 {
 706         struct gameport_driver *driver = to_gameport_driver(drv);
 707         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 708 }
 709
 710 static struct driver_attribute gameport_driver_attrs[] = {
 711         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 712         __ATTR_NULL
 713 };
 714
 715 static int gameport_driver_probe(struct device *dev)
 716 {
 717         struct gameport *gameport = to_gameport_port(dev);
 718         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 719
 720         drv->connect(gameport, drv);
 721         return gameport->drv ? 0 : -ENODEV;
 722 }
 723
 724 static int gameport_driver_remove(struct device *dev)
 725 {
 726         struct gameport *gameport = to_gameport_port(dev);
 727         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 728
 729         drv->disconnect(gameport);
 730         return 0;
 731 }
 732
 733 static struct bus_type gameport_bus = {
 734         .name   = "gameport",
 735         .probe  = gameport_driver_probe,
 736         .remove = gameport_driver_remove,
 737 };
 738
 739 static void gameport_add_driver(struct gameport_driver *drv)
 740 {
 741         int error;
 742
 743         error = driver_register(&drv->driver);
 744         if (error)
 745                 printk(KERN_ERR
 746                         "gameport: driver_register() failed for %s, error: %d\n",
 747                         drv->driver.name, error);
 748 }
 749
 750 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
 751 {
 752         drv->driver.bus = &gameport_bus;
 753         gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
 754 }
 755
 756 void gameport_unregister_driver(struct gameport_driver *drv)
 757 {
 758         struct gameport *gameport;
 759
 760         mutex_lock(&gameport_mutex);
 761         drv->ignore = 1;        /* so gameport_find_driver ignores it */
 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         mutex_unlock(&gameport_mutex);
 775 }
 776
 777 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 778 {
 779         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 780
 781         return !gameport_drv->ignore;
 782 }
 783
 784 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 785 {
 786         mutex_lock(&gameport->drv_mutex);
 787         gameport->drv = drv;
 788         mutex_unlock(&gameport->drv_mutex);
 789 }
 790
 791 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 792 {
 793
 794         if (gameport->open) {
 795                 if (gameport->open(gameport, mode)) {
 796                         return -1;
 797                 }
 798         } else {
 799                 if (mode != GAMEPORT_MODE_RAW)
 800                         return -1;
 801         }
 802
 803         gameport_set_drv(gameport, drv);
 804         return 0;
 805 }
 806
 807 void gameport_close(struct gameport *gameport)
 808 {
 809         del_timer_sync(&gameport->poll_timer);
 810         gameport->poll_handler = NULL;
 811         gameport->poll_interval = 0;
 812         gameport_set_drv(gameport, NULL);
 813         if (gameport->close)
 814                 gameport->close(gameport);
 815 }
 816
 817 static int __init gameport_init(void)
 818 {
 819         int error;
 820
 821         gameport_bus.dev_attrs = gameport_device_attrs;
 822         gameport_bus.drv_attrs = gameport_driver_attrs;
 823         gameport_bus.match = gameport_bus_match;
 824         error = bus_register(&gameport_bus);
 825         if (error) {
 826                 printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
 827                 return error;
 828         }
 829
 830         gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 831         if (IS_ERR(gameport_task)) {
 832                 bus_unregister(&gameport_bus);
 833                 error = PTR_ERR(gameport_task);
 834                 printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
 835                 return error;
 836         }
 837
 838         return 0;
 839 }
 840
 841 static void __exit gameport_exit(void)
 842 {
 843         bus_unregister(&gameport_bus);
 844         kthread_stop(gameport_task);
 845 }
 846
 847 subsys_initcall(gameport_init);
 848 module_exit(gameport_exit);