1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Generic gameport layer 4 * 5 * Copyright (c) 1999-2002 Vojtech Pavlik 6 * Copyright (c) 2005 Dmitry Torokhov 7 */ 8 9 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12 #include <linux/stddef.h> 13 #include <linux/module.h> 14 #include <linux/io.h> 15 #include <linux/ioport.h> 16 #include <linux/init.h> 17 #include <linux/gameport.h> 18 #include <linux/slab.h> 19 #include <linux/delay.h> 20 #include <linux/workqueue.h> 21 #include <linux/sched.h> /* HZ */ 22 #include <linux/mutex.h> 23 #include <linux/timekeeping.h> 24 25 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 26 MODULE_DESCRIPTION("Generic gameport layer"); 27 MODULE_LICENSE("GPL"); 28 29 static bool use_ktime = true; 30 module_param(use_ktime, bool, 0400); 31 MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed"); 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 unsigned int i, t, tx; 80 u64 t1, t2, t3; 81 unsigned long flags; 82 83 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 84 return 0; 85 86 tx = ~0; 87 88 for (i = 0; i < 50; i++) { 89 local_irq_save(flags); 90 t1 = ktime_get_ns(); 91 for (t = 0; t < 50; t++) 92 gameport_read(gameport); 93 t2 = ktime_get_ns(); 94 t3 = ktime_get_ns(); 95 local_irq_restore(flags); 96 udelay(i * 10); 97 t = (t2 - t1) - (t3 - t2); 98 if (t < tx) 99 tx = t; 100 } 101 102 gameport_close(gameport); 103 t = 1000000 * 50; 104 if (tx) 105 t /= tx; 106 return t; 107 } 108 109 static int old_gameport_measure_speed(struct gameport *gameport) 110 { 111 #if defined(__i386__) 112 113 unsigned int i, t, t1, t2, t3, tx; 114 unsigned long flags; 115 116 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 117 return 0; 118 119 tx = 1 << 30; 120 121 for(i = 0; i < 50; i++) { 122 local_irq_save(flags); 123 GET_TIME(t1); 124 for (t = 0; t < 50; t++) gameport_read(gameport); 125 GET_TIME(t2); 126 GET_TIME(t3); 127 local_irq_restore(flags); 128 udelay(i * 10); 129 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t; 130 } 131 132 gameport_close(gameport); 133 return 59659 / (tx < 1 ? 1 : tx); 134 135 #elif defined (__x86_64__) 136 137 unsigned int i, t; 138 unsigned long tx, t1, t2, flags; 139 140 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 141 return 0; 142 143 tx = 1 << 30; 144 145 for(i = 0; i < 50; i++) { 146 local_irq_save(flags); 147 t1 = rdtsc(); 148 for (t = 0; t < 50; t++) gameport_read(gameport); 149 t2 = rdtsc(); 150 local_irq_restore(flags); 151 udelay(i * 10); 152 if (t2 - t1 < tx) tx = t2 - t1; 153 } 154 155 gameport_close(gameport); 156 return (this_cpu_read(cpu_info.loops_per_jiffy) * 157 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx); 158 159 #else 160 161 unsigned int j, t = 0; 162 163 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 164 return 0; 165 166 j = jiffies; while (j == jiffies); 167 j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); } 168 169 gameport_close(gameport); 170 return t * HZ / 1000; 171 172 #endif 173 } 174 175 void gameport_start_polling(struct gameport *gameport) 176 { 177 spin_lock(&gameport->timer_lock); 178 179 if (!gameport->poll_cnt++) { 180 BUG_ON(!gameport->poll_handler); 181 BUG_ON(!gameport->poll_interval); 182 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval)); 183 } 184 185 spin_unlock(&gameport->timer_lock); 186 } 187 EXPORT_SYMBOL(gameport_start_polling); 188 189 void gameport_stop_polling(struct gameport *gameport) 190 { 191 spin_lock(&gameport->timer_lock); 192 193 if (!--gameport->poll_cnt) 194 del_timer(&gameport->poll_timer); 195 196 spin_unlock(&gameport->timer_lock); 197 } 198 EXPORT_SYMBOL(gameport_stop_polling); 199 200 static void gameport_run_poll_handler(struct timer_list *t) 201 { 202 struct gameport *gameport = from_timer(gameport, t, poll_timer); 203 204 gameport->poll_handler(gameport); 205 if (gameport->poll_cnt) 206 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval)); 207 } 208 209 /* 210 * Basic gameport -> driver core mappings 211 */ 212 213 static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv) 214 { 215 int error; 216 217 gameport->dev.driver = &drv->driver; 218 if (drv->connect(gameport, drv)) { 219 gameport->dev.driver = NULL; 220 return -ENODEV; 221 } 222 223 error = device_bind_driver(&gameport->dev); 224 if (error) { 225 dev_warn(&gameport->dev, 226 "device_bind_driver() failed for %s (%s) and %s, error: %d\n", 227 gameport->phys, gameport->name, 228 drv->description, error); 229 drv->disconnect(gameport); 230 gameport->dev.driver = NULL; 231 return error; 232 } 233 234 return 0; 235 } 236 237 static void gameport_find_driver(struct gameport *gameport) 238 { 239 int error; 240 241 error = device_attach(&gameport->dev); 242 if (error < 0) 243 dev_warn(&gameport->dev, 244 "device_attach() failed for %s (%s), error: %d\n", 245 gameport->phys, gameport->name, error); 246 } 247 248 249 /* 250 * Gameport event processing. 251 */ 252 253 enum gameport_event_type { 254 GAMEPORT_REGISTER_PORT, 255 GAMEPORT_ATTACH_DRIVER, 256 }; 257 258 struct gameport_event { 259 enum gameport_event_type type; 260 void *object; 261 struct module *owner; 262 struct list_head node; 263 }; 264 265 static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */ 266 static LIST_HEAD(gameport_event_list); 267 268 static struct gameport_event *gameport_get_event(void) 269 { 270 struct gameport_event *event = NULL; 271 unsigned long flags; 272 273 spin_lock_irqsave(&gameport_event_lock, flags); 274 275 if (!list_empty(&gameport_event_list)) { 276 event = list_first_entry(&gameport_event_list, 277 struct gameport_event, node); 278 list_del_init(&event->node); 279 } 280 281 spin_unlock_irqrestore(&gameport_event_lock, flags); 282 return event; 283 } 284 285 static void gameport_free_event(struct gameport_event *event) 286 { 287 module_put(event->owner); 288 kfree(event); 289 } 290 291 static void gameport_remove_duplicate_events(struct gameport_event *event) 292 { 293 struct gameport_event *e, *next; 294 unsigned long flags; 295 296 spin_lock_irqsave(&gameport_event_lock, flags); 297 298 list_for_each_entry_safe(e, next, &gameport_event_list, node) { 299 if (event->object == e->object) { 300 /* 301 * If this event is of different type we should not 302 * look further - we only suppress duplicate events 303 * that were sent back-to-back. 304 */ 305 if (event->type != e->type) 306 break; 307 308 list_del_init(&e->node); 309 gameport_free_event(e); 310 } 311 } 312 313 spin_unlock_irqrestore(&gameport_event_lock, flags); 314 } 315 316 317 static void gameport_handle_events(struct work_struct *work) 318 { 319 struct gameport_event *event; 320 321 mutex_lock(&gameport_mutex); 322 323 /* 324 * Note that we handle only one event here to give swsusp 325 * a chance to freeze kgameportd thread. Gameport events 326 * should be pretty rare so we are not concerned about 327 * taking performance hit. 328 */ 329 if ((event = gameport_get_event())) { 330 331 switch (event->type) { 332 333 case GAMEPORT_REGISTER_PORT: 334 gameport_add_port(event->object); 335 break; 336 337 case GAMEPORT_ATTACH_DRIVER: 338 gameport_attach_driver(event->object); 339 break; 340 } 341 342 gameport_remove_duplicate_events(event); 343 gameport_free_event(event); 344 } 345 346 mutex_unlock(&gameport_mutex); 347 } 348 349 static DECLARE_WORK(gameport_event_work, gameport_handle_events); 350 351 static int gameport_queue_event(void *object, struct module *owner, 352 enum gameport_event_type event_type) 353 { 354 unsigned long flags; 355 struct gameport_event *event; 356 int retval = 0; 357 358 spin_lock_irqsave(&gameport_event_lock, flags); 359 360 /* 361 * Scan event list for the other events for the same gameport port, 362 * starting with the most recent one. If event is the same we 363 * do not need add new one. If event is of different type we 364 * need to add this event and should not look further because 365 * we need to preserve sequence of distinct events. 366 */ 367 list_for_each_entry_reverse(event, &gameport_event_list, node) { 368 if (event->object == object) { 369 if (event->type == event_type) 370 goto out; 371 break; 372 } 373 } 374 375 event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC); 376 if (!event) { 377 pr_err("Not enough memory to queue event %d\n", event_type); 378 retval = -ENOMEM; 379 goto out; 380 } 381 382 if (!try_module_get(owner)) { 383 pr_warn("Can't get module reference, dropping event %d\n", 384 event_type); 385 kfree(event); 386 retval = -EINVAL; 387 goto out; 388 } 389 390 event->type = event_type; 391 event->object = object; 392 event->owner = owner; 393 394 list_add_tail(&event->node, &gameport_event_list); 395 queue_work(system_long_wq, &gameport_event_work); 396 397 out: 398 spin_unlock_irqrestore(&gameport_event_lock, flags); 399 return retval; 400 } 401 402 /* 403 * Remove all events that have been submitted for a given object, 404 * be it a gameport port or a driver. 405 */ 406 static void gameport_remove_pending_events(void *object) 407 { 408 struct gameport_event *event, *next; 409 unsigned long flags; 410 411 spin_lock_irqsave(&gameport_event_lock, flags); 412 413 list_for_each_entry_safe(event, next, &gameport_event_list, node) { 414 if (event->object == object) { 415 list_del_init(&event->node); 416 gameport_free_event(event); 417 } 418 } 419 420 spin_unlock_irqrestore(&gameport_event_lock, flags); 421 } 422 423 /* 424 * Destroy child gameport port (if any) that has not been fully registered yet. 425 * 426 * Note that we rely on the fact that port can have only one child and therefore 427 * only one child registration request can be pending. Additionally, children 428 * are registered by driver's connect() handler so there can't be a grandchild 429 * pending registration together with a child. 430 */ 431 static struct gameport *gameport_get_pending_child(struct gameport *parent) 432 { 433 struct gameport_event *event; 434 struct gameport *gameport, *child = NULL; 435 unsigned long flags; 436 437 spin_lock_irqsave(&gameport_event_lock, flags); 438 439 list_for_each_entry(event, &gameport_event_list, node) { 440 if (event->type == GAMEPORT_REGISTER_PORT) { 441 gameport = event->object; 442 if (gameport->parent == parent) { 443 child = gameport; 444 break; 445 } 446 } 447 } 448 449 spin_unlock_irqrestore(&gameport_event_lock, flags); 450 return child; 451 } 452 453 /* 454 * Gameport port operations 455 */ 456 457 static ssize_t gameport_description_show(struct device *dev, struct device_attribute *attr, char *buf) 458 { 459 struct gameport *gameport = to_gameport_port(dev); 460 461 return sprintf(buf, "%s\n", gameport->name); 462 } 463 static DEVICE_ATTR(description, S_IRUGO, gameport_description_show, NULL); 464 465 static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 466 { 467 struct gameport *gameport = to_gameport_port(dev); 468 struct device_driver *drv; 469 int error; 470 471 error = mutex_lock_interruptible(&gameport_mutex); 472 if (error) 473 return error; 474 475 if (!strncmp(buf, "none", count)) { 476 gameport_disconnect_port(gameport); 477 } else if (!strncmp(buf, "reconnect", count)) { 478 gameport_reconnect_port(gameport); 479 } else if (!strncmp(buf, "rescan", count)) { 480 gameport_disconnect_port(gameport); 481 gameport_find_driver(gameport); 482 } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) { 483 gameport_disconnect_port(gameport); 484 error = gameport_bind_driver(gameport, to_gameport_driver(drv)); 485 } else { 486 error = -EINVAL; 487 } 488 489 mutex_unlock(&gameport_mutex); 490 491 return error ? error : count; 492 } 493 static DEVICE_ATTR_WO(drvctl); 494 495 static struct attribute *gameport_device_attrs[] = { 496 &dev_attr_description.attr, 497 &dev_attr_drvctl.attr, 498 NULL, 499 }; 500 ATTRIBUTE_GROUPS(gameport_device); 501 502 static void gameport_release_port(struct device *dev) 503 { 504 struct gameport *gameport = to_gameport_port(dev); 505 506 kfree(gameport); 507 module_put(THIS_MODULE); 508 } 509 510 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...) 511 { 512 va_list args; 513 514 va_start(args, fmt); 515 vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args); 516 va_end(args); 517 } 518 EXPORT_SYMBOL(gameport_set_phys); 519 520 static void gameport_default_trigger(struct gameport *gameport) 521 { 522 outb(0xff, gameport->io); 523 } 524 525 static unsigned char gameport_default_read(struct gameport *gameport) 526 { 527 return inb(gameport->io); 528 } 529 530 /* 531 * Prepare gameport port for registration. 532 */ 533 static void gameport_init_port(struct gameport *gameport) 534 { 535 static atomic_t gameport_no = ATOMIC_INIT(-1); 536 537 __module_get(THIS_MODULE); 538 539 mutex_init(&gameport->drv_mutex); 540 device_initialize(&gameport->dev); 541 dev_set_name(&gameport->dev, "gameport%lu", 542 (unsigned long)atomic_inc_return(&gameport_no)); 543 gameport->dev.bus = &gameport_bus; 544 gameport->dev.release = gameport_release_port; 545 if (gameport->parent) 546 gameport->dev.parent = &gameport->parent->dev; 547 548 if (!gameport->trigger) 549 gameport->trigger = gameport_default_trigger; 550 if (!gameport->read) 551 gameport->read = gameport_default_read; 552 553 INIT_LIST_HEAD(&gameport->node); 554 spin_lock_init(&gameport->timer_lock); 555 timer_setup(&gameport->poll_timer, gameport_run_poll_handler, 0); 556 } 557 558 /* 559 * Complete gameport port registration. 560 * Driver core will attempt to find appropriate driver for the port. 561 */ 562 static void gameport_add_port(struct gameport *gameport) 563 { 564 int error; 565 566 if (gameport->parent) 567 gameport->parent->child = gameport; 568 569 gameport->speed = use_ktime ? 570 gameport_measure_speed(gameport) : 571 old_gameport_measure_speed(gameport); 572 573 list_add_tail(&gameport->node, &gameport_list); 574 575 if (gameport->io) 576 dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n", 577 gameport->name, gameport->phys, gameport->io, gameport->speed); 578 else 579 dev_info(&gameport->dev, "%s is %s, speed %dkHz\n", 580 gameport->name, gameport->phys, gameport->speed); 581 582 error = device_add(&gameport->dev); 583 if (error) 584 dev_err(&gameport->dev, 585 "device_add() failed for %s (%s), error: %d\n", 586 gameport->phys, gameport->name, error); 587 } 588 589 /* 590 * gameport_destroy_port() completes deregistration process and removes 591 * port from the system 592 */ 593 static void gameport_destroy_port(struct gameport *gameport) 594 { 595 struct gameport *child; 596 597 child = gameport_get_pending_child(gameport); 598 if (child) { 599 gameport_remove_pending_events(child); 600 put_device(&child->dev); 601 } 602 603 if (gameport->parent) { 604 gameport->parent->child = NULL; 605 gameport->parent = NULL; 606 } 607 608 if (device_is_registered(&gameport->dev)) 609 device_del(&gameport->dev); 610 611 list_del_init(&gameport->node); 612 613 gameport_remove_pending_events(gameport); 614 put_device(&gameport->dev); 615 } 616 617 /* 618 * Reconnect gameport port and all its children (re-initialize attached devices) 619 */ 620 static void gameport_reconnect_port(struct gameport *gameport) 621 { 622 do { 623 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) { 624 gameport_disconnect_port(gameport); 625 gameport_find_driver(gameport); 626 /* Ok, old children are now gone, we are done */ 627 break; 628 } 629 gameport = gameport->child; 630 } while (gameport); 631 } 632 633 /* 634 * gameport_disconnect_port() unbinds a port from its driver. As a side effect 635 * all child ports are unbound and destroyed. 636 */ 637 static void gameport_disconnect_port(struct gameport *gameport) 638 { 639 struct gameport *s, *parent; 640 641 if (gameport->child) { 642 /* 643 * Children ports should be disconnected and destroyed 644 * first, staring with the leaf one, since we don't want 645 * to do recursion 646 */ 647 for (s = gameport; s->child; s = s->child) 648 /* empty */; 649 650 do { 651 parent = s->parent; 652 653 device_release_driver(&s->dev); 654 gameport_destroy_port(s); 655 } while ((s = parent) != gameport); 656 } 657 658 /* 659 * Ok, no children left, now disconnect this port 660 */ 661 device_release_driver(&gameport->dev); 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 EXPORT_SYMBOL(__gameport_register_port); 674 675 /* 676 * Synchronously unregisters gameport port. 677 */ 678 void gameport_unregister_port(struct gameport *gameport) 679 { 680 mutex_lock(&gameport_mutex); 681 gameport_disconnect_port(gameport); 682 gameport_destroy_port(gameport); 683 mutex_unlock(&gameport_mutex); 684 } 685 EXPORT_SYMBOL(gameport_unregister_port); 686 687 688 /* 689 * Gameport driver operations 690 */ 691 692 static ssize_t description_show(struct device_driver *drv, char *buf) 693 { 694 struct gameport_driver *driver = to_gameport_driver(drv); 695 return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)"); 696 } 697 static DRIVER_ATTR_RO(description); 698 699 static struct attribute *gameport_driver_attrs[] = { 700 &driver_attr_description.attr, 701 NULL 702 }; 703 ATTRIBUTE_GROUPS(gameport_driver); 704 705 static int gameport_driver_probe(struct device *dev) 706 { 707 struct gameport *gameport = to_gameport_port(dev); 708 struct gameport_driver *drv = to_gameport_driver(dev->driver); 709 710 drv->connect(gameport, drv); 711 return gameport->drv ? 0 : -ENODEV; 712 } 713 714 static void gameport_driver_remove(struct device *dev) 715 { 716 struct gameport *gameport = to_gameport_port(dev); 717 struct gameport_driver *drv = to_gameport_driver(dev->driver); 718 719 drv->disconnect(gameport); 720 } 721 722 static void gameport_attach_driver(struct gameport_driver *drv) 723 { 724 int error; 725 726 error = driver_attach(&drv->driver); 727 if (error) 728 pr_err("driver_attach() failed for %s, error: %d\n", 729 drv->driver.name, error); 730 } 731 732 int __gameport_register_driver(struct gameport_driver *drv, struct module *owner, 733 const char *mod_name) 734 { 735 int error; 736 737 drv->driver.bus = &gameport_bus; 738 drv->driver.owner = owner; 739 drv->driver.mod_name = mod_name; 740 741 /* 742 * Temporarily disable automatic binding because probing 743 * takes long time and we are better off doing it in kgameportd 744 */ 745 drv->ignore = true; 746 747 error = driver_register(&drv->driver); 748 if (error) { 749 pr_err("driver_register() failed for %s, error: %d\n", 750 drv->driver.name, error); 751 return error; 752 } 753 754 /* 755 * Reset ignore flag and let kgameportd bind the driver to free ports 756 */ 757 drv->ignore = false; 758 error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER); 759 if (error) { 760 driver_unregister(&drv->driver); 761 return error; 762 } 763 764 return 0; 765 } 766 EXPORT_SYMBOL(__gameport_register_driver); 767 768 void gameport_unregister_driver(struct gameport_driver *drv) 769 { 770 struct gameport *gameport; 771 772 mutex_lock(&gameport_mutex); 773 774 drv->ignore = true; /* so gameport_find_driver ignores it */ 775 gameport_remove_pending_events(drv); 776 777 start_over: 778 list_for_each_entry(gameport, &gameport_list, node) { 779 if (gameport->drv == drv) { 780 gameport_disconnect_port(gameport); 781 gameport_find_driver(gameport); 782 /* we could've deleted some ports, restart */ 783 goto start_over; 784 } 785 } 786 787 driver_unregister(&drv->driver); 788 789 mutex_unlock(&gameport_mutex); 790 } 791 EXPORT_SYMBOL(gameport_unregister_driver); 792 793 static int gameport_bus_match(struct device *dev, struct device_driver *drv) 794 { 795 struct gameport_driver *gameport_drv = to_gameport_driver(drv); 796 797 return !gameport_drv->ignore; 798 } 799 800 static struct bus_type gameport_bus = { 801 .name = "gameport", 802 .dev_groups = gameport_device_groups, 803 .drv_groups = gameport_driver_groups, 804 .match = gameport_bus_match, 805 .probe = gameport_driver_probe, 806 .remove = gameport_driver_remove, 807 }; 808 809 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv) 810 { 811 mutex_lock(&gameport->drv_mutex); 812 gameport->drv = drv; 813 mutex_unlock(&gameport->drv_mutex); 814 } 815 816 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode) 817 { 818 if (gameport->open) { 819 if (gameport->open(gameport, mode)) { 820 return -1; 821 } 822 } else { 823 if (mode != GAMEPORT_MODE_RAW) 824 return -1; 825 } 826 827 gameport_set_drv(gameport, drv); 828 return 0; 829 } 830 EXPORT_SYMBOL(gameport_open); 831 832 void gameport_close(struct gameport *gameport) 833 { 834 del_timer_sync(&gameport->poll_timer); 835 gameport->poll_handler = NULL; 836 gameport->poll_interval = 0; 837 gameport_set_drv(gameport, NULL); 838 if (gameport->close) 839 gameport->close(gameport); 840 } 841 EXPORT_SYMBOL(gameport_close); 842 843 static int __init gameport_init(void) 844 { 845 int error; 846 847 error = bus_register(&gameport_bus); 848 if (error) { 849 pr_err("failed to register gameport bus, error: %d\n", error); 850 return error; 851 } 852 853 854 return 0; 855 } 856 857 static void __exit gameport_exit(void) 858 { 859 bus_unregister(&gameport_bus); 860 861 /* 862 * There should not be any outstanding events but work may 863 * still be scheduled so simply cancel it. 864 */ 865 cancel_work_sync(&gameport_event_work); 866 } 867 868 subsys_initcall(gameport_init); 869 module_exit(gameport_exit); 870