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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/stddef.h>
  17 #include <linux/module.h>
  18 #include <linux/ioport.h>
  19 #include <linux/init.h>
  20 #include <linux/gameport.h>
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/workqueue.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 /*
  34  * gameport_mutex protects entire gameport subsystem and is taken
  35  * every time gameport port or driver registrered or unregistered.
  36  */
  37 static DEFINE_MUTEX(gameport_mutex);
  38
  39 static LIST_HEAD(gameport_list);
  40
  41 static struct bus_type gameport_bus;
  42
  43 static void gameport_add_port(struct gameport *gameport);
  44 static void gameport_attach_driver(struct gameport_driver *drv);
  45 static void gameport_reconnect_port(struct gameport *gameport);
  46 static void gameport_disconnect_port(struct gameport *gameport);
  47
  48 #if defined(__i386__)
  49
  50 #include <linux/i8253.h>
  51
  52 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
  53 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
  54
  55 static unsigned int get_time_pit(void)
  56 {
  57         unsigned long flags;
  58         unsigned int count;
  59
  60         raw_spin_lock_irqsave(&i8253_lock, flags);
  61         outb_p(0x00, 0x43);
  62         count = inb_p(0x40);
  63         count |= inb_p(0x40) << 8;
  64         raw_spin_unlock_irqrestore(&i8253_lock, flags);
  65
  66         return count;
  67 }
  68
  69 #endif
  70
  71
  72
  73 /*
  74  * gameport_measure_speed() measures the gameport i/o speed.
  75  */
  76
  77 static int gameport_measure_speed(struct gameport *gameport)
  78 {
  79 #if defined(__i386__)
  80
  81         unsigned int i, t, t1, t2, t3, tx;
  82         unsigned long flags;
  83
  84         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  85                 return 0;
  86
  87         tx = 1 << 30;
  88
  89         for(i = 0; i < 50; i++) {
  90                 local_irq_save(flags);
  91                 GET_TIME(t1);
  92                 for (t = 0; t < 50; t++) gameport_read(gameport);
  93                 GET_TIME(t2);
  94                 GET_TIME(t3);
  95                 local_irq_restore(flags);
  96                 udelay(i * 10);
  97                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
  98         }
  99
 100         gameport_close(gameport);
 101         return 59659 / (tx < 1 ? 1 : tx);
 102
 103 #elif defined (__x86_64__)
 104
 105         unsigned int i, t;
 106         unsigned long tx, t1, t2, flags;
 107
 108         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 109                 return 0;
 110
 111         tx = 1 << 30;
 112
 113         for(i = 0; i < 50; i++) {
 114                 local_irq_save(flags);
 115                 rdtscl(t1);
 116                 for (t = 0; t < 50; t++) gameport_read(gameport);
 117                 rdtscl(t2);
 118                 local_irq_restore(flags);
 119                 udelay(i * 10);
 120                 if (t2 - t1 < tx) tx = t2 - t1;
 121         }
 122
 123         gameport_close(gameport);
 124         return (this_cpu_read(cpu_info.loops_per_jiffy) *
 125                 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
 126
 127 #else
 128
 129         unsigned int j, t = 0;
 130
 131         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 132                 return 0;
 133
 134         j = jiffies; while (j == jiffies);
 135         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
 136
 137         gameport_close(gameport);
 138         return t * HZ / 1000;
 139
 140 #endif
 141 }
 142
 143 void gameport_start_polling(struct gameport *gameport)
 144 {
 145         spin_lock(&gameport->timer_lock);
 146
 147         if (!gameport->poll_cnt++) {
 148                 BUG_ON(!gameport->poll_handler);
 149                 BUG_ON(!gameport->poll_interval);
 150                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 151         }
 152
 153         spin_unlock(&gameport->timer_lock);
 154 }
 155 EXPORT_SYMBOL(gameport_start_polling);
 156
 157 void gameport_stop_polling(struct gameport *gameport)
 158 {
 159         spin_lock(&gameport->timer_lock);
 160
 161         if (!--gameport->poll_cnt)
 162                 del_timer(&gameport->poll_timer);
 163
 164         spin_unlock(&gameport->timer_lock);
 165 }
 166 EXPORT_SYMBOL(gameport_stop_polling);
 167
 168 static void gameport_run_poll_handler(unsigned long d)
 169 {
 170         struct gameport *gameport = (struct gameport *)d;
 171
 172         gameport->poll_handler(gameport);
 173         if (gameport->poll_cnt)
 174                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 175 }
 176
 177 /*
 178  * Basic gameport -> driver core mappings
 179  */
 180
 181 static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 182 {
 183         int error;
 184
 185         gameport->dev.driver = &drv->driver;
 186         if (drv->connect(gameport, drv)) {
 187                 gameport->dev.driver = NULL;
 188                 return -ENODEV;
 189         }
 190
 191         error = device_bind_driver(&gameport->dev);
 192         if (error) {
 193                 dev_warn(&gameport->dev,
 194                          "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
 195                         gameport->phys, gameport->name,
 196                         drv->description, error);
 197                 drv->disconnect(gameport);
 198                 gameport->dev.driver = NULL;
 199                 return error;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static void gameport_find_driver(struct gameport *gameport)
 206 {
 207         int error;
 208
 209         error = device_attach(&gameport->dev);
 210         if (error < 0)
 211                 dev_warn(&gameport->dev,
 212                          "device_attach() failed for %s (%s), error: %d\n",
 213                          gameport->phys, gameport->name, error);
 214 }
 215
 216
 217 /*
 218  * Gameport event processing.
 219  */
 220
 221 enum gameport_event_type {
 222         GAMEPORT_REGISTER_PORT,
 223         GAMEPORT_ATTACH_DRIVER,
 224 };
 225
 226 struct gameport_event {
 227         enum gameport_event_type type;
 228         void *object;
 229         struct module *owner;
 230         struct list_head node;
 231 };
 232
 233 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
 234 static LIST_HEAD(gameport_event_list);
 235
 236 static struct gameport_event *gameport_get_event(void)
 237 {
 238         struct gameport_event *event = NULL;
 239         unsigned long flags;
 240
 241         spin_lock_irqsave(&gameport_event_lock, flags);
 242
 243         if (!list_empty(&gameport_event_list)) {
 244                 event = list_first_entry(&gameport_event_list,
 245                                          struct gameport_event, node);
 246                 list_del_init(&event->node);
 247         }
 248
 249         spin_unlock_irqrestore(&gameport_event_lock, flags);
 250         return event;
 251 }
 252
 253 static void gameport_free_event(struct gameport_event *event)
 254 {
 255         module_put(event->owner);
 256         kfree(event);
 257 }
 258
 259 static void gameport_remove_duplicate_events(struct gameport_event *event)
 260 {
 261         struct gameport_event *e, *next;
 262         unsigned long flags;
 263
 264         spin_lock_irqsave(&gameport_event_lock, flags);
 265
 266         list_for_each_entry_safe(e, next, &gameport_event_list, node) {
 267                 if (event->object == e->object) {
 268                         /*
 269                          * If this event is of different type we should not
 270                          * look further - we only suppress duplicate events
 271                          * that were sent back-to-back.
 272                          */
 273                         if (event->type != e->type)
 274                                 break;
 275
 276                         list_del_init(&e->node);
 277                         gameport_free_event(e);
 278                 }
 279         }
 280
 281         spin_unlock_irqrestore(&gameport_event_lock, flags);
 282 }
 283
 284
 285 static void gameport_handle_events(struct work_struct *work)
 286 {
 287         struct gameport_event *event;
 288
 289         mutex_lock(&gameport_mutex);
 290
 291         /*
 292          * Note that we handle only one event here to give swsusp
 293          * a chance to freeze kgameportd thread. Gameport events
 294          * should be pretty rare so we are not concerned about
 295          * taking performance hit.
 296          */
 297         if ((event = gameport_get_event())) {
 298
 299                 switch (event->type) {
 300
 301                 case GAMEPORT_REGISTER_PORT:
 302                         gameport_add_port(event->object);
 303                         break;
 304
 305                 case GAMEPORT_ATTACH_DRIVER:
 306                         gameport_attach_driver(event->object);
 307                         break;
 308                 }
 309
 310                 gameport_remove_duplicate_events(event);
 311                 gameport_free_event(event);
 312         }
 313
 314         mutex_unlock(&gameport_mutex);
 315 }
 316
 317 static DECLARE_WORK(gameport_event_work, gameport_handle_events);
 318
 319 static int gameport_queue_event(void *object, struct module *owner,
 320                                 enum gameport_event_type event_type)
 321 {
 322         unsigned long flags;
 323         struct gameport_event *event;
 324         int retval = 0;
 325
 326         spin_lock_irqsave(&gameport_event_lock, flags);
 327
 328         /*
 329          * Scan event list for the other events for the same gameport port,
 330          * starting with the most recent one. If event is the same we
 331          * do not need add new one. If event is of different type we
 332          * need to add this event and should not look further because
 333          * we need to preserve sequence of distinct events.
 334          */
 335         list_for_each_entry_reverse(event, &gameport_event_list, node) {
 336                 if (event->object == object) {
 337                         if (event->type == event_type)
 338                                 goto out;
 339                         break;
 340                 }
 341         }
 342
 343         event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
 344         if (!event) {
 345                 pr_err("Not enough memory to queue event %d\n", event_type);
 346                 retval = -ENOMEM;
 347                 goto out;
 348         }
 349
 350         if (!try_module_get(owner)) {
 351                 pr_warning("Can't get module reference, dropping event %d\n",
 352                            event_type);
 353                 kfree(event);
 354                 retval = -EINVAL;
 355                 goto out;
 356         }
 357
 358         event->type = event_type;
 359         event->object = object;
 360         event->owner = owner;
 361
 362         list_add_tail(&event->node, &gameport_event_list);
 363         queue_work(system_long_wq, &gameport_event_work);
 364
 365 out:
 366         spin_unlock_irqrestore(&gameport_event_lock, flags);
 367         return retval;
 368 }
 369
 370 /*
 371  * Remove all events that have been submitted for a given object,
 372  * be it a gameport port or a driver.
 373  */
 374 static void gameport_remove_pending_events(void *object)
 375 {
 376         struct gameport_event *event, *next;
 377         unsigned long flags;
 378
 379         spin_lock_irqsave(&gameport_event_lock, flags);
 380
 381         list_for_each_entry_safe(event, next, &gameport_event_list, node) {
 382                 if (event->object == object) {
 383                         list_del_init(&event->node);
 384                         gameport_free_event(event);
 385                 }
 386         }
 387
 388         spin_unlock_irqrestore(&gameport_event_lock, flags);
 389 }
 390
 391 /*
 392  * Destroy child gameport port (if any) that has not been fully registered yet.
 393  *
 394  * Note that we rely on the fact that port can have only one child and therefore
 395  * only one child registration request can be pending. Additionally, children
 396  * are registered by driver's connect() handler so there can't be a grandchild
 397  * pending registration together with a child.
 398  */
 399 static struct gameport *gameport_get_pending_child(struct gameport *parent)
 400 {
 401         struct gameport_event *event;
 402         struct gameport *gameport, *child = NULL;
 403         unsigned long flags;
 404
 405         spin_lock_irqsave(&gameport_event_lock, flags);
 406
 407         list_for_each_entry(event, &gameport_event_list, node) {
 408                 if (event->type == GAMEPORT_REGISTER_PORT) {
 409                         gameport = event->object;
 410                         if (gameport->parent == parent) {
 411                                 child = gameport;
 412                                 break;
 413                         }
 414                 }
 415         }
 416
 417         spin_unlock_irqrestore(&gameport_event_lock, flags);
 418         return child;
 419 }
 420
 421 /*
 422  * Gameport port operations
 423  */
 424
 425 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 426 {
 427         struct gameport *gameport = to_gameport_port(dev);
 428
 429         return sprintf(buf, "%s\n", gameport->name);
 430 }
 431
 432 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 433 {
 434         struct gameport *gameport = to_gameport_port(dev);
 435         struct device_driver *drv;
 436         int error;
 437
 438         error = mutex_lock_interruptible(&gameport_mutex);
 439         if (error)
 440                 return error;
 441
 442         if (!strncmp(buf, "none", count)) {
 443                 gameport_disconnect_port(gameport);
 444         } else if (!strncmp(buf, "reconnect", count)) {
 445                 gameport_reconnect_port(gameport);
 446         } else if (!strncmp(buf, "rescan", count)) {
 447                 gameport_disconnect_port(gameport);
 448                 gameport_find_driver(gameport);
 449         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 450                 gameport_disconnect_port(gameport);
 451                 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
 452         } else {
 453                 error = -EINVAL;
 454         }
 455
 456         mutex_unlock(&gameport_mutex);
 457
 458         return error ? error : count;
 459 }
 460
 461 static struct device_attribute gameport_device_attrs[] = {
 462         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
 463         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 464         __ATTR_NULL
 465 };
 466
 467 static void gameport_release_port(struct device *dev)
 468 {
 469         struct gameport *gameport = to_gameport_port(dev);
 470
 471         kfree(gameport);
 472         module_put(THIS_MODULE);
 473 }
 474
 475 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 476 {
 477         va_list args;
 478
 479         va_start(args, fmt);
 480         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 481         va_end(args);
 482 }
 483 EXPORT_SYMBOL(gameport_set_phys);
 484
 485 /*
 486  * Prepare gameport port for registration.
 487  */
 488 static void gameport_init_port(struct gameport *gameport)
 489 {
 490         static atomic_t gameport_no = ATOMIC_INIT(0);
 491
 492         __module_get(THIS_MODULE);
 493
 494         mutex_init(&gameport->drv_mutex);
 495         device_initialize(&gameport->dev);
 496         dev_set_name(&gameport->dev, "gameport%lu",
 497                         (unsigned long)atomic_inc_return(&gameport_no) - 1);
 498         gameport->dev.bus = &gameport_bus;
 499         gameport->dev.release = gameport_release_port;
 500         if (gameport->parent)
 501                 gameport->dev.parent = &gameport->parent->dev;
 502
 503         INIT_LIST_HEAD(&gameport->node);
 504         spin_lock_init(&gameport->timer_lock);
 505         init_timer(&gameport->poll_timer);
 506         gameport->poll_timer.function = gameport_run_poll_handler;
 507         gameport->poll_timer.data = (unsigned long)gameport;
 508 }
 509
 510 /*
 511  * Complete gameport port registration.
 512  * Driver core will attempt to find appropriate driver for the port.
 513  */
 514 static void gameport_add_port(struct gameport *gameport)
 515 {
 516         int error;
 517
 518         if (gameport->parent)
 519                 gameport->parent->child = gameport;
 520
 521         gameport->speed = gameport_measure_speed(gameport);
 522
 523         list_add_tail(&gameport->node, &gameport_list);
 524
 525         if (gameport->io)
 526                 dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n",
 527                          gameport->name, gameport->phys, gameport->io, gameport->speed);
 528         else
 529                 dev_info(&gameport->dev, "%s is %s, speed %dkHz\n",
 530                         gameport->name, gameport->phys, gameport->speed);
 531
 532         error = device_add(&gameport->dev);
 533         if (error)
 534                 dev_err(&gameport->dev,
 535                         "device_add() failed for %s (%s), error: %d\n",
 536                         gameport->phys, gameport->name, error);
 537 }
 538
 539 /*
 540  * gameport_destroy_port() completes deregistration process and removes
 541  * port from the system
 542  */
 543 static void gameport_destroy_port(struct gameport *gameport)
 544 {
 545         struct gameport *child;
 546
 547         child = gameport_get_pending_child(gameport);
 548         if (child) {
 549                 gameport_remove_pending_events(child);
 550                 put_device(&child->dev);
 551         }
 552
 553         if (gameport->parent) {
 554                 gameport->parent->child = NULL;
 555                 gameport->parent = NULL;
 556         }
 557
 558         if (device_is_registered(&gameport->dev))
 559                 device_del(&gameport->dev);
 560
 561         list_del_init(&gameport->node);
 562
 563         gameport_remove_pending_events(gameport);
 564         put_device(&gameport->dev);
 565 }
 566
 567 /*
 568  * Reconnect gameport port and all its children (re-initialize attached devices)
 569  */
 570 static void gameport_reconnect_port(struct gameport *gameport)
 571 {
 572         do {
 573                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 574                         gameport_disconnect_port(gameport);
 575                         gameport_find_driver(gameport);
 576                         /* Ok, old children are now gone, we are done */
 577                         break;
 578                 }
 579                 gameport = gameport->child;
 580         } while (gameport);
 581 }
 582
 583 /*
 584  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 585  * all child ports are unbound and destroyed.
 586  */
 587 static void gameport_disconnect_port(struct gameport *gameport)
 588 {
 589         struct gameport *s, *parent;
 590
 591         if (gameport->child) {
 592                 /*
 593                  * Children ports should be disconnected and destroyed
 594                  * first, staring with the leaf one, since we don't want
 595                  * to do recursion
 596                  */
 597                 for (s = gameport; s->child; s = s->child)
 598                         /* empty */;
 599
 600                 do {
 601                         parent = s->parent;
 602
 603                         device_release_driver(&s->dev);
 604                         gameport_destroy_port(s);
 605                 } while ((s = parent) != gameport);
 606         }
 607
 608         /*
 609          * Ok, no children left, now disconnect this port
 610          */
 611         device_release_driver(&gameport->dev);
 612 }
 613
 614 /*
 615  * Submits register request to kgameportd for subsequent execution.
 616  * Note that port registration is always asynchronous.
 617  */
 618 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 619 {
 620         gameport_init_port(gameport);
 621         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 622 }
 623 EXPORT_SYMBOL(__gameport_register_port);
 624
 625 /*
 626  * Synchronously unregisters gameport port.
 627  */
 628 void gameport_unregister_port(struct gameport *gameport)
 629 {
 630         mutex_lock(&gameport_mutex);
 631         gameport_disconnect_port(gameport);
 632         gameport_destroy_port(gameport);
 633         mutex_unlock(&gameport_mutex);
 634 }
 635 EXPORT_SYMBOL(gameport_unregister_port);
 636
 637
 638 /*
 639  * Gameport driver operations
 640  */
 641
 642 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
 643 {
 644         struct gameport_driver *driver = to_gameport_driver(drv);
 645         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 646 }
 647
 648 static struct driver_attribute gameport_driver_attrs[] = {
 649         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 650         __ATTR_NULL
 651 };
 652
 653 static int gameport_driver_probe(struct device *dev)
 654 {
 655         struct gameport *gameport = to_gameport_port(dev);
 656         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 657
 658         drv->connect(gameport, drv);
 659         return gameport->drv ? 0 : -ENODEV;
 660 }
 661
 662 static int gameport_driver_remove(struct device *dev)
 663 {
 664         struct gameport *gameport = to_gameport_port(dev);
 665         struct gameport_driver *drv = to_gameport_driver(dev->driver);
 666
 667         drv->disconnect(gameport);
 668         return 0;
 669 }
 670
 671 static void gameport_attach_driver(struct gameport_driver *drv)
 672 {
 673         int error;
 674
 675         error = driver_attach(&drv->driver);
 676         if (error)
 677                 pr_err("driver_attach() failed for %s, error: %d\n",
 678                         drv->driver.name, error);
 679 }
 680
 681 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
 682                                 const char *mod_name)
 683 {
 684         int error;
 685
 686         drv->driver.bus = &gameport_bus;
 687         drv->driver.owner = owner;
 688         drv->driver.mod_name = mod_name;
 689
 690         /*
 691          * Temporarily disable automatic binding because probing
 692          * takes long time and we are better off doing it in kgameportd
 693          */
 694         drv->ignore = true;
 695
 696         error = driver_register(&drv->driver);
 697         if (error) {
 698                 pr_err("driver_register() failed for %s, error: %d\n",
 699                         drv->driver.name, error);
 700                 return error;
 701         }
 702
 703         /*
 704          * Reset ignore flag and let kgameportd bind the driver to free ports
 705          */
 706         drv->ignore = false;
 707         error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
 708         if (error) {
 709                 driver_unregister(&drv->driver);
 710                 return error;
 711         }
 712
 713         return 0;
 714 }
 715 EXPORT_SYMBOL(__gameport_register_driver);
 716
 717 void gameport_unregister_driver(struct gameport_driver *drv)
 718 {
 719         struct gameport *gameport;
 720
 721         mutex_lock(&gameport_mutex);
 722
 723         drv->ignore = true;     /* so gameport_find_driver ignores it */
 724         gameport_remove_pending_events(drv);
 725
 726 start_over:
 727         list_for_each_entry(gameport, &gameport_list, node) {
 728                 if (gameport->drv == drv) {
 729                         gameport_disconnect_port(gameport);
 730                         gameport_find_driver(gameport);
 731                         /* we could've deleted some ports, restart */
 732                         goto start_over;
 733                 }
 734         }
 735
 736         driver_unregister(&drv->driver);
 737
 738         mutex_unlock(&gameport_mutex);
 739 }
 740 EXPORT_SYMBOL(gameport_unregister_driver);
 741
 742 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 743 {
 744         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
 745
 746         return !gameport_drv->ignore;
 747 }
 748
 749 static struct bus_type gameport_bus = {
 750         .name           = "gameport",
 751         .dev_attrs      = gameport_device_attrs,
 752         .drv_attrs      = gameport_driver_attrs,
 753         .match          = gameport_bus_match,
 754         .probe          = gameport_driver_probe,
 755         .remove         = gameport_driver_remove,
 756 };
 757
 758 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 759 {
 760         mutex_lock(&gameport->drv_mutex);
 761         gameport->drv = drv;
 762         mutex_unlock(&gameport->drv_mutex);
 763 }
 764
 765 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 766 {
 767         if (gameport->open) {
 768                 if (gameport->open(gameport, mode)) {
 769                         return -1;
 770                 }
 771         } else {
 772                 if (mode != GAMEPORT_MODE_RAW)
 773                         return -1;
 774         }
 775
 776         gameport_set_drv(gameport, drv);
 777         return 0;
 778 }
 779 EXPORT_SYMBOL(gameport_open);
 780
 781 void gameport_close(struct gameport *gameport)
 782 {
 783         del_timer_sync(&gameport->poll_timer);
 784         gameport->poll_handler = NULL;
 785         gameport->poll_interval = 0;
 786         gameport_set_drv(gameport, NULL);
 787         if (gameport->close)
 788                 gameport->close(gameport);
 789 }
 790 EXPORT_SYMBOL(gameport_close);
 791
 792 static int __init gameport_init(void)
 793 {
 794         int error;
 795
 796         error = bus_register(&gameport_bus);
 797         if (error) {
 798                 pr_err("failed to register gameport bus, error: %d\n", error);
 799                 return error;
 800         }
 801
 802
 803         return 0;
 804 }
 805
 806 static void __exit gameport_exit(void)
 807 {
 808         bus_unregister(&gameport_bus);
 809
 810         /*
 811          * There should not be any outstanding events but work may
 812          * still be scheduled so simply cancel it.
 813          */
 814         cancel_work_sync(&gameport_event_work);
 815 }
 816
 817 subsys_initcall(gameport_init);
 818 module_exit(gameport_exit);