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/wait.h> 22#include <linux/slab.h> 23#include <linux/delay.h> 24#include <linux/kthread.h> 25#include <linux/sched.h> /* HZ */ 26#include <linux/mutex.h> 27#include <linux/freezer.h> 28 29/*#include <asm/io.h>*/ 30 31MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 32MODULE_DESCRIPTION("Generic gameport layer"); 33MODULE_LICENSE("GPL"); 34 35/* 36 * gameport_mutex protects entire gameport subsystem and is taken 37 * every time gameport port or driver registrered or unregistered. 38 */ 39static DEFINE_MUTEX(gameport_mutex); 40 41static LIST_HEAD(gameport_list); 42 43static struct bus_type gameport_bus; 44 45static void gameport_add_port(struct gameport *gameport); 46static void gameport_attach_driver(struct gameport_driver *drv); 47static void gameport_reconnect_port(struct gameport *gameport); 48static void gameport_disconnect_port(struct gameport *gameport); 49 50#if defined(__i386__) 51 52#include <asm/i8253.h> 53 54#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0)) 55#define GET_TIME(x) do { x = get_time_pit(); } while (0) 56 57static unsigned int get_time_pit(void) 58{ 59 unsigned long flags; 60 unsigned int count; 61 62 raw_spin_lock_irqsave(&i8253_lock, flags); 63 outb_p(0x00, 0x43); 64 count = inb_p(0x40); 65 count |= inb_p(0x40) << 8; 66 raw_spin_unlock_irqrestore(&i8253_lock, flags); 67 68 return count; 69} 70 71#endif 72 73 74 75/* 76 * gameport_measure_speed() measures the gameport i/o speed. 77 */ 78 79static int gameport_measure_speed(struct gameport *gameport) 80{ 81#if defined(__i386__) 82 83 unsigned int i, t, t1, t2, t3, tx; 84 unsigned long flags; 85 86 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 87 return 0; 88 89 tx = 1 << 30; 90 91 for(i = 0; i < 50; i++) { 92 local_irq_save(flags); 93 GET_TIME(t1); 94 for (t = 0; t < 50; t++) gameport_read(gameport); 95 GET_TIME(t2); 96 GET_TIME(t3); 97 local_irq_restore(flags); 98 udelay(i * 10); 99 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t; 100 } 101 102 gameport_close(gameport); 103 return 59659 / (tx < 1 ? 1 : tx); 104 105#elif defined(__x86_64__) 106 107 unsigned int i, t; 108 unsigned long tx, t1, t2, flags; 109 110 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 111 return 0; 112 113 tx = 1 << 30; 114 115 for(i = 0; i < 50; i++) { 116 local_irq_save(flags); 117 rdtscl(t1); 118 for (t = 0; t < 50; t++) gameport_read(gameport); 119 rdtscl(t2); 120 local_irq_restore(flags); 121 udelay(i * 10); 122 if (t2 - t1 < tx) tx = t2 - t1; 123 } 124 125 gameport_close(gameport); 126 return (cpu_data(raw_smp_processor_id()).loops_per_jiffy * 127 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx); 128 129#else 130 131 unsigned int j, t = 0; 132 133 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) 134 return 0; 135 136 j = jiffies; while (j == jiffies); 137 j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); } 138 139 gameport_close(gameport); 140 return t * HZ / 1000; 141 142#endif 143} 144 145void gameport_start_polling(struct gameport *gameport) 146{ 147 spin_lock(&gameport->timer_lock); 148 149 if (!gameport->poll_cnt++) { 150 BUG_ON(!gameport->poll_handler); 151 BUG_ON(!gameport->poll_interval); 152 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval)); 153 } 154 155 spin_unlock(&gameport->timer_lock); 156} 157EXPORT_SYMBOL(gameport_start_polling); 158 159void gameport_stop_polling(struct gameport *gameport) 160{ 161 spin_lock(&gameport->timer_lock); 162 163 if (!--gameport->poll_cnt) 164 del_timer(&gameport->poll_timer); 165 166 spin_unlock(&gameport->timer_lock); 167} 168EXPORT_SYMBOL(gameport_stop_polling); 169 170static void gameport_run_poll_handler(unsigned long d) 171{ 172 struct gameport *gameport = (struct gameport *)d; 173 174 gameport->poll_handler(gameport); 175 if (gameport->poll_cnt) 176 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval)); 177} 178 179/* 180 * Basic gameport -> driver core mappings 181 */ 182 183static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv) 184{ 185 int error; 186 187 gameport->dev.driver = &drv->driver; 188 if (drv->connect(gameport, drv)) { 189 gameport->dev.driver = NULL; 190 return -ENODEV; 191 } 192 193 error = device_bind_driver(&gameport->dev); 194 if (error) { 195 dev_warn(&gameport->dev, 196 "device_bind_driver() failed for %s (%s) and %s, error: %d\n", 197 gameport->phys, gameport->name, 198 drv->description, error); 199 drv->disconnect(gameport); 200 gameport->dev.driver = NULL; 201 return error; 202 } 203 204 return 0; 205} 206 207static void gameport_find_driver(struct gameport *gameport) 208{ 209 int error; 210 211 error = device_attach(&gameport->dev); 212 if (error < 0) 213 dev_warn(&gameport->dev, 214 "device_attach() failed for %s (%s), error: %d\n", 215 gameport->phys, gameport->name, error); 216} 217 218 219/* 220 * Gameport event processing. 221 */ 222 223enum gameport_event_type { 224 GAMEPORT_REGISTER_PORT, 225 GAMEPORT_ATTACH_DRIVER, 226}; 227 228struct gameport_event { 229 enum gameport_event_type type; 230 void *object; 231 struct module *owner; 232 struct list_head node; 233}; 234 235static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */ 236static LIST_HEAD(gameport_event_list); 237static DECLARE_WAIT_QUEUE_HEAD(gameport_wait); 238static struct task_struct *gameport_task; 239 240static int gameport_queue_event(void *object, struct module *owner, 241 enum gameport_event_type event_type) 242{ 243 unsigned long flags; 244 struct gameport_event *event; 245 int retval = 0; 246 247 spin_lock_irqsave(&gameport_event_lock, flags); 248 249 /* 250 * Scan event list for the other events for the same gameport port, 251 * starting with the most recent one. If event is the same we 252 * do not need add new one. If event is of different type we 253 * need to add this event and should not look further because 254 * we need to preseve sequence of distinct events. 255 */ 256 list_for_each_entry_reverse(event, &gameport_event_list, node) { 257 if (event->object == object) { 258 if (event->type == event_type) 259 goto out; 260 break; 261 } 262 } 263 264 event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC); 265 if (!event) { 266 pr_err("Not enough memory to queue event %d\n", event_type); 267 retval = -ENOMEM; 268 goto out; 269 } 270 271 if (!try_module_get(owner)) { 272 pr_warning("Can't get module reference, dropping event %d\n", 273 event_type); 274 kfree(event); 275 retval = -EINVAL; 276 goto out; 277 } 278 279 event->type = event_type; 280 event->object = object; 281 event->owner = owner; 282 283 list_add_tail(&event->node, &gameport_event_list); 284 wake_up(&gameport_wait); 285 286out: 287 spin_unlock_irqrestore(&gameport_event_lock, flags); 288 return retval; 289} 290 291static void gameport_free_event(struct gameport_event *event) 292{ 293 module_put(event->owner); 294 kfree(event); 295} 296 297static void gameport_remove_duplicate_events(struct gameport_event *event) 298{ 299 struct gameport_event *e, *next; 300 unsigned long flags; 301 302 spin_lock_irqsave(&gameport_event_lock, flags); 303 304 list_for_each_entry_safe(e, next, &gameport_event_list, node) { 305 if (event->object == e->object) { 306 /* 307 * If this event is of different type we should not 308 * look further - we only suppress duplicate events 309 * that were sent back-to-back. 310 */ 311 if (event->type != e->type) 312 break; 313 314 list_del_init(&e->node); 315 gameport_free_event(e); 316 } 317 } 318 319 spin_unlock_irqrestore(&gameport_event_lock, flags); 320} 321 322static struct gameport_event *gameport_get_event(void) 323{ 324 struct gameport_event *event = NULL; 325 unsigned long flags; 326 327 spin_lock_irqsave(&gameport_event_lock, flags); 328 329 if (!list_empty(&gameport_event_list)) { 330 event = list_first_entry(&gameport_event_list, 331 struct gameport_event, node); 332 list_del_init(&event->node); 333 } 334 335 spin_unlock_irqrestore(&gameport_event_lock, flags); 336 return event; 337} 338 339static void gameport_handle_event(void) 340{ 341 struct gameport_event *event; 342 343 mutex_lock(&gameport_mutex); 344 345 /* 346 * Note that we handle only one event here to give swsusp 347 * a chance to freeze kgameportd thread. Gameport events 348 * should be pretty rare so we are not concerned about 349 * taking performance hit. 350 */ 351 if ((event = gameport_get_event())) { 352 353 switch (event->type) { 354 355 case GAMEPORT_REGISTER_PORT: 356 gameport_add_port(event->object); 357 break; 358 359 case GAMEPORT_ATTACH_DRIVER: 360 gameport_attach_driver(event->object); 361 break; 362 } 363 364 gameport_remove_duplicate_events(event); 365 gameport_free_event(event); 366 } 367 368 mutex_unlock(&gameport_mutex); 369} 370 371/* 372 * Remove all events that have been submitted for a given object, 373 * be it a gameport port or a driver. 374 */ 375static void gameport_remove_pending_events(void *object) 376{ 377 struct gameport_event *event, *next; 378 unsigned long flags; 379 380 spin_lock_irqsave(&gameport_event_lock, flags); 381 382 list_for_each_entry_safe(event, next, &gameport_event_list, node) { 383 if (event->object == object) { 384 list_del_init(&event->node); 385 gameport_free_event(event); 386 } 387 } 388 389 spin_unlock_irqrestore(&gameport_event_lock, flags); 390} 391 392/* 393 * Destroy child gameport port (if any) that has not been fully registered yet. 394 * 395 * Note that we rely on the fact that port can have only one child and therefore 396 * only one child registration request can be pending. Additionally, children 397 * are registered by driver's connect() handler so there can't be a grandchild 398 * pending registration together with a child. 399 */ 400static struct gameport *gameport_get_pending_child(struct gameport *parent) 401{ 402 struct gameport_event *event; 403 struct gameport *gameport, *child = NULL; 404 unsigned long flags; 405 406 spin_lock_irqsave(&gameport_event_lock, flags); 407 408 list_for_each_entry(event, &gameport_event_list, node) { 409 if (event->type == GAMEPORT_REGISTER_PORT) { 410 gameport = event->object; 411 if (gameport->parent == parent) { 412 child = gameport; 413 break; 414 } 415 } 416 } 417 418 spin_unlock_irqrestore(&gameport_event_lock, flags); 419 return child; 420} 421 422static int gameport_thread(void *nothing) 423{ 424 set_freezable(); 425 do { 426 gameport_handle_event(); 427 wait_event_freezable(gameport_wait, 428 kthread_should_stop() || !list_empty(&gameport_event_list)); 429 } while (!kthread_should_stop()); 430 431 return 0; 432} 433 434 435/* 436 * Gameport port operations 437 */ 438 439static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf) 440{ 441 struct gameport *gameport = to_gameport_port(dev); 442 443 return sprintf(buf, "%s\n", gameport->name); 444} 445 446static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 447{ 448 struct gameport *gameport = to_gameport_port(dev); 449 struct device_driver *drv; 450 int error; 451 452 error = mutex_lock_interruptible(&gameport_mutex); 453 if (error) 454 return error; 455 456 if (!strncmp(buf, "none", count)) { 457 gameport_disconnect_port(gameport); 458 } else if (!strncmp(buf, "reconnect", count)) { 459 gameport_reconnect_port(gameport); 460 } else if (!strncmp(buf, "rescan", count)) { 461 gameport_disconnect_port(gameport); 462 gameport_find_driver(gameport); 463 } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) { 464 gameport_disconnect_port(gameport); 465 error = gameport_bind_driver(gameport, to_gameport_driver(drv)); 466 put_driver(drv); 467 } else { 468 error = -EINVAL; 469 } 470 471 mutex_unlock(&gameport_mutex); 472 473 return error ? error : count; 474} 475 476static struct device_attribute gameport_device_attrs[] = { 477 __ATTR(description, S_IRUGO, gameport_show_description, NULL), 478 __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver), 479 __ATTR_NULL 480}; 481 482static void gameport_release_port(struct device *dev) 483{ 484 struct gameport *gameport = to_gameport_port(dev); 485 486 kfree(gameport); 487 module_put(THIS_MODULE); 488} 489 490void gameport_set_phys(struct gameport *gameport, const char *fmt, ...) 491{ 492 va_list args; 493 494 va_start(args, fmt); 495 vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args); 496 va_end(args); 497} 498EXPORT_SYMBOL(gameport_set_phys); 499 500/* 501 * Prepare gameport port for registration. 502 */ 503static void gameport_init_port(struct gameport *gameport) 504{ 505 static atomic_t gameport_no = ATOMIC_INIT(0); 506 507 __module_get(THIS_MODULE); 508 509 mutex_init(&gameport->drv_mutex); 510 device_initialize(&gameport->dev); 511 dev_set_name(&gameport->dev, "gameport%lu", 512 (unsigned long)atomic_inc_return(&gameport_no) - 1); 513 gameport->dev.bus = &gameport_bus; 514 gameport->dev.release = gameport_release_port; 515 if (gameport->parent) 516 gameport->dev.parent = &gameport->parent->dev; 517 518 INIT_LIST_HEAD(&gameport->node); 519 spin_lock_init(&gameport->timer_lock); 520 init_timer(&gameport->poll_timer); 521 gameport->poll_timer.function = gameport_run_poll_handler; 522 gameport->poll_timer.data = (unsigned long)gameport; 523} 524 525/* 526 * Complete gameport port registration. 527 * Driver core will attempt to find appropriate driver for the port. 528 */ 529static void gameport_add_port(struct gameport *gameport) 530{ 531 int error; 532 533 if (gameport->parent) 534 gameport->parent->child = gameport; 535 536 gameport->speed = gameport_measure_speed(gameport); 537 538 list_add_tail(&gameport->node, &gameport_list); 539 540 if (gameport->io) 541 dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n", 542 gameport->name, gameport->phys, gameport->io, gameport->speed); 543 else 544 dev_info(&gameport->dev, "%s is %s, speed %dkHz\n", 545 gameport->name, gameport->phys, gameport->speed); 546 547 error = device_add(&gameport->dev); 548 if (error) 549 dev_err(&gameport->dev, 550 "device_add() failed for %s (%s), error: %d\n", 551 gameport->phys, gameport->name, error); 552} 553 554/* 555 * gameport_destroy_port() completes deregistration process and removes 556 * port from the system 557 */ 558static void gameport_destroy_port(struct gameport *gameport) 559{ 560 struct gameport *child; 561 562 child = gameport_get_pending_child(gameport); 563 if (child) { 564 gameport_remove_pending_events(child); 565 put_device(&child->dev); 566 } 567 568 if (gameport->parent) { 569 gameport->parent->child = NULL; 570 gameport->parent = NULL; 571 } 572 573 if (device_is_registered(&gameport->dev)) 574 device_del(&gameport->dev); 575 576 list_del_init(&gameport->node); 577 578 gameport_remove_pending_events(gameport); 579 put_device(&gameport->dev); 580} 581 582/* 583 * Reconnect gameport port and all its children (re-initialize attached devices) 584 */ 585static void gameport_reconnect_port(struct gameport *gameport) 586{ 587 do { 588 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) { 589 gameport_disconnect_port(gameport); 590 gameport_find_driver(gameport); 591 /* Ok, old children are now gone, we are done */ 592 break; 593 } 594 gameport = gameport->child; 595 } while (gameport); 596} 597 598/* 599 * gameport_disconnect_port() unbinds a port from its driver. As a side effect 600 * all child ports are unbound and destroyed. 601 */ 602static void gameport_disconnect_port(struct gameport *gameport) 603{ 604 struct gameport *s, *parent; 605 606 if (gameport->child) { 607 /* 608 * Children ports should be disconnected and destroyed 609 * first, staring with the leaf one, since we don't want 610 * to do recursion 611 */ 612 for (s = gameport; s->child; s = s->child) 613 /* empty */; 614 615 do { 616 parent = s->parent; 617 618 device_release_driver(&s->dev); 619 gameport_destroy_port(s); 620 } while ((s = parent) != gameport); 621 } 622 623 /* 624 * Ok, no children left, now disconnect this port 625 */ 626 device_release_driver(&gameport->dev); 627} 628 629/* 630 * Submits register request to kgameportd for subsequent execution. 631 * Note that port registration is always asynchronous. 632 */ 633void __gameport_register_port(struct gameport *gameport, struct module *owner) 634{ 635 gameport_init_port(gameport); 636 gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT); 637} 638EXPORT_SYMBOL(__gameport_register_port); 639 640/* 641 * Synchronously unregisters gameport port. 642 */ 643void gameport_unregister_port(struct gameport *gameport) 644{ 645 mutex_lock(&gameport_mutex); 646 gameport_disconnect_port(gameport); 647 gameport_destroy_port(gameport); 648 mutex_unlock(&gameport_mutex); 649} 650EXPORT_SYMBOL(gameport_unregister_port); 651 652 653/* 654 * Gameport driver operations 655 */ 656 657static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf) 658{ 659 struct gameport_driver *driver = to_gameport_driver(drv); 660 return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)"); 661} 662 663static struct driver_attribute gameport_driver_attrs[] = { 664 __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL), 665 __ATTR_NULL 666}; 667 668static int gameport_driver_probe(struct device *dev) 669{ 670 struct gameport *gameport = to_gameport_port(dev); 671 struct gameport_driver *drv = to_gameport_driver(dev->driver); 672 673 drv->connect(gameport, drv); 674 return gameport->drv ? 0 : -ENODEV; 675} 676 677static int gameport_driver_remove(struct device *dev) 678{ 679 struct gameport *gameport = to_gameport_port(dev); 680 struct gameport_driver *drv = to_gameport_driver(dev->driver); 681 682 drv->disconnect(gameport); 683 return 0; 684} 685 686static void gameport_attach_driver(struct gameport_driver *drv) 687{ 688 int error; 689 690 error = driver_attach(&drv->driver); 691 if (error) 692 pr_err("driver_attach() failed for %s, error: %d\n", 693 drv->driver.name, error); 694} 695 696int __gameport_register_driver(struct gameport_driver *drv, struct module *owner, 697 const char *mod_name) 698{ 699 int error; 700 701 drv->driver.bus = &gameport_bus; 702 drv->driver.owner = owner; 703 drv->driver.mod_name = mod_name; 704 705 /* 706 * Temporarily disable automatic binding because probing 707 * takes long time and we are better off doing it in kgameportd 708 */ 709 drv->ignore = true; 710 711 error = driver_register(&drv->driver); 712 if (error) { 713 pr_err("driver_register() failed for %s, error: %d\n", 714 drv->driver.name, error); 715 return error; 716 } 717 718 /* 719 * Reset ignore flag and let kgameportd bind the driver to free ports 720 */ 721 drv->ignore = false; 722 error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER); 723 if (error) { 724 driver_unregister(&drv->driver); 725 return error; 726 } 727 728 return 0; 729} 730EXPORT_SYMBOL(__gameport_register_driver); 731 732void gameport_unregister_driver(struct gameport_driver *drv) 733{ 734 struct gameport *gameport; 735 736 mutex_lock(&gameport_mutex); 737 738 drv->ignore = true; /* so gameport_find_driver ignores it */ 739 gameport_remove_pending_events(drv); 740 741start_over: 742 list_for_each_entry(gameport, &gameport_list, node) { 743 if (gameport->drv == drv) { 744 gameport_disconnect_port(gameport); 745 gameport_find_driver(gameport); 746 /* we could've deleted some ports, restart */ 747 goto start_over; 748 } 749 } 750 751 driver_unregister(&drv->driver); 752 753 mutex_unlock(&gameport_mutex); 754} 755EXPORT_SYMBOL(gameport_unregister_driver); 756 757static int gameport_bus_match(struct device *dev, struct device_driver *drv) 758{ 759 struct gameport_driver *gameport_drv = to_gameport_driver(drv); 760 761 return !gameport_drv->ignore; 762} 763 764static struct bus_type gameport_bus = { 765 .name = "gameport", 766 .dev_attrs = gameport_device_attrs, 767 .drv_attrs = gameport_driver_attrs, 768 .match = gameport_bus_match, 769 .probe = gameport_driver_probe, 770 .remove = gameport_driver_remove, 771}; 772 773static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv) 774{ 775 mutex_lock(&gameport->drv_mutex); 776 gameport->drv = drv; 777 mutex_unlock(&gameport->drv_mutex); 778} 779 780int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode) 781{ 782 if (gameport->open) { 783 if (gameport->open(gameport, mode)) { 784 return -1; 785 } 786 } else { 787 if (mode != GAMEPORT_MODE_RAW) 788 return -1; 789 } 790 791 gameport_set_drv(gameport, drv); 792 return 0; 793} 794EXPORT_SYMBOL(gameport_open); 795 796void gameport_close(struct gameport *gameport) 797{ 798 del_timer_sync(&gameport->poll_timer); 799 gameport->poll_handler = NULL; 800 gameport->poll_interval = 0; 801 gameport_set_drv(gameport, NULL); 802 if (gameport->close) 803 gameport->close(gameport); 804} 805EXPORT_SYMBOL(gameport_close); 806 807static int __init gameport_init(void) 808{ 809 int error; 810 811 error = bus_register(&gameport_bus); 812 if (error) { 813 pr_err("failed to register gameport bus, error: %d\n", error); 814 return error; 815 } 816 817 gameport_task = kthread_run(gameport_thread, NULL, "kgameportd"); 818 if (IS_ERR(gameport_task)) { 819 bus_unregister(&gameport_bus); 820 error = PTR_ERR(gameport_task); 821 pr_err("Failed to start kgameportd, error: %d\n", error); 822 return error; 823 } 824 825 return 0; 826} 827 828static void __exit gameport_exit(void) 829{ 830 bus_unregister(&gameport_bus); 831 kthread_stop(gameport_task); 832} 833 834subsys_initcall(gameport_init); 835module_exit(gameport_exit); 836