e152d0fa0cdd25d4d4ac4de364eaf80b9502a0cc
[linux-2.6.git] / 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/completion.h>
21 #include <linux/sched.h>
22 #include <linux/smp_lock.h>
23 #include <linux/slab.h>
24 #include <linux/delay.h>
25
26 /*#include <asm/io.h>*/
27
28 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
29 MODULE_DESCRIPTION("Generic gameport layer");
30 MODULE_LICENSE("GPL");
31
32 EXPORT_SYMBOL(__gameport_register_port);
33 EXPORT_SYMBOL(gameport_unregister_port);
34 EXPORT_SYMBOL(__gameport_register_driver);
35 EXPORT_SYMBOL(gameport_unregister_driver);
36 EXPORT_SYMBOL(gameport_open);
37 EXPORT_SYMBOL(gameport_close);
38 EXPORT_SYMBOL(gameport_rescan);
39 EXPORT_SYMBOL(gameport_cooked_read);
40 EXPORT_SYMBOL(gameport_set_name);
41 EXPORT_SYMBOL(gameport_set_phys);
42 EXPORT_SYMBOL(gameport_start_polling);
43 EXPORT_SYMBOL(gameport_stop_polling);
44
45 /*
46  * gameport_sem protects entire gameport subsystem and is taken
47  * every time gameport port or driver registrered or unregistered.
48  */
49 static DECLARE_MUTEX(gameport_sem);
50
51 static LIST_HEAD(gameport_list);
52
53 static struct bus_type gameport_bus = {
54         .name = "gameport",
55 };
56
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 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
65 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)
66
67 static unsigned int get_time_pit(void)
68 {
69         extern spinlock_t i8253_lock;
70         unsigned long flags;
71         unsigned int count;
72
73         spin_lock_irqsave(&i8253_lock, flags);
74         outb_p(0x00, 0x43);
75         count = inb_p(0x40);
76         count |= inb_p(0x40) << 8;
77         spin_unlock_irqrestore(&i8253_lock, flags);
78
79         return count;
80 }
81
82 #endif
83
84
85
86 /*
87  * gameport_measure_speed() measures the gameport i/o speed.
88  */
89
90 static int gameport_measure_speed(struct gameport *gameport)
91 {
92 #if defined(__i386__)
93
94         unsigned int i, t, t1, t2, t3, tx;
95         unsigned long flags;
96
97         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
98                 return 0;
99
100         tx = 1 << 30;
101
102         for(i = 0; i < 50; i++) {
103                 local_irq_save(flags);
104                 GET_TIME(t1);
105                 for (t = 0; t < 50; t++) gameport_read(gameport);
106                 GET_TIME(t2);
107                 GET_TIME(t3);
108                 local_irq_restore(flags);
109                 udelay(i * 10);
110                 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
111         }
112
113         gameport_close(gameport);
114         return 59659 / (tx < 1 ? 1 : tx);
115
116 #elif defined (__x86_64__)
117
118         unsigned int i, t;
119         unsigned long tx, t1, t2, flags;
120
121         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
122                 return 0;
123
124         tx = 1 << 30;
125
126         for(i = 0; i < 50; i++) {
127                 local_irq_save(flags);
128                 rdtscl(t1);
129                 for (t = 0; t < 50; t++) gameport_read(gameport);
130                 rdtscl(t2);
131                 local_irq_restore(flags);
132                 udelay(i * 10);
133                 if (t2 - t1 < tx) tx = t2 - t1;
134         }
135
136         gameport_close(gameport);
137         return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
138
139 #else
140
141         unsigned int j, t = 0;
142
143         if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
144                 return 0;
145
146         j = jiffies; while (j == jiffies);
147         j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
148
149         gameport_close(gameport);
150         return t * HZ / 1000;
151
152 #endif
153 }
154
155 void gameport_start_polling(struct gameport *gameport)
156 {
157         spin_lock(&gameport->timer_lock);
158
159         if (!gameport->poll_cnt++) {
160                 BUG_ON(!gameport->poll_handler);
161                 BUG_ON(!gameport->poll_interval);
162                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
163         }
164
165         spin_unlock(&gameport->timer_lock);
166 }
167
168 void gameport_stop_polling(struct gameport *gameport)
169 {
170         spin_lock(&gameport->timer_lock);
171
172         if (!--gameport->poll_cnt)
173                 del_timer(&gameport->poll_timer);
174
175         spin_unlock(&gameport->timer_lock);
176 }
177
178 static void gameport_run_poll_handler(unsigned long d)
179 {
180         struct gameport *gameport = (struct gameport *)d;
181
182         gameport->poll_handler(gameport);
183         if (gameport->poll_cnt)
184                 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
185 }
186
187 /*
188  * Basic gameport -> driver core mappings
189  */
190
191 static void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
192 {
193         down_write(&gameport_bus.subsys.rwsem);
194
195         gameport->dev.driver = &drv->driver;
196         if (drv->connect(gameport, drv)) {
197                 gameport->dev.driver = NULL;
198                 goto out;
199         }
200         device_bind_driver(&gameport->dev);
201 out:
202         up_write(&gameport_bus.subsys.rwsem);
203 }
204
205 static void gameport_release_driver(struct gameport *gameport)
206 {
207         down_write(&gameport_bus.subsys.rwsem);
208         device_release_driver(&gameport->dev);
209         up_write(&gameport_bus.subsys.rwsem);
210 }
211
212 static void gameport_find_driver(struct gameport *gameport)
213 {
214         down_write(&gameport_bus.subsys.rwsem);
215         device_attach(&gameport->dev);
216         up_write(&gameport_bus.subsys.rwsem);
217 }
218
219
220 /*
221  * Gameport event processing.
222  */
223
224 enum gameport_event_type {
225         GAMEPORT_RESCAN,
226         GAMEPORT_RECONNECT,
227         GAMEPORT_REGISTER_PORT,
228         GAMEPORT_REGISTER_DRIVER,
229 };
230
231 struct gameport_event {
232         enum gameport_event_type type;
233         void *object;
234         struct module *owner;
235         struct list_head node;
236 };
237
238 static DEFINE_SPINLOCK(gameport_event_lock);    /* protects gameport_event_list */
239 static LIST_HEAD(gameport_event_list);
240 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
241 static DECLARE_COMPLETION(gameport_exited);
242 static int gameport_pid;
243
244 static void gameport_queue_event(void *object, struct module *owner,
245                               enum gameport_event_type event_type)
246 {
247         unsigned long flags;
248         struct gameport_event *event;
249
250         spin_lock_irqsave(&gameport_event_lock, flags);
251
252         /*
253          * Scan event list for the other events for the same gameport port,
254          * starting with the most recent one. If event is the same we
255          * do not need add new one. If event is of different type we
256          * need to add this event and should not look further because
257          * we need to preseve sequence of distinct events.
258          */
259         list_for_each_entry_reverse(event, &gameport_event_list, node) {
260                 if (event->object == object) {
261                         if (event->type == event_type)
262                                 goto out;
263                         break;
264                 }
265         }
266
267         if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
268                 if (!try_module_get(owner)) {
269                         printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
270                         goto out;
271                 }
272
273                 event->type = event_type;
274                 event->object = object;
275                 event->owner = owner;
276
277                 list_add_tail(&event->node, &gameport_event_list);
278                 wake_up(&gameport_wait);
279         } else {
280                 printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
281         }
282 out:
283         spin_unlock_irqrestore(&gameport_event_lock, flags);
284 }
285
286 static void gameport_free_event(struct gameport_event *event)
287 {
288         module_put(event->owner);
289         kfree(event);
290 }
291
292 static void gameport_remove_duplicate_events(struct gameport_event *event)
293 {
294         struct list_head *node, *next;
295         struct gameport_event *e;
296         unsigned long flags;
297
298         spin_lock_irqsave(&gameport_event_lock, flags);
299
300         list_for_each_safe(node, next, &gameport_event_list) {
301                 e = list_entry(node, struct gameport_event, node);
302                 if (event->object == e->object) {
303                         /*
304                          * If this event is of different type we should not
305                          * look further - we only suppress duplicate events
306                          * that were sent back-to-back.
307                          */
308                         if (event->type != e->type)
309                                 break;
310
311                         list_del_init(node);
312                         gameport_free_event(e);
313                 }
314         }
315
316         spin_unlock_irqrestore(&gameport_event_lock, flags);
317 }
318
319
320 static struct gameport_event *gameport_get_event(void)
321 {
322         struct gameport_event *event;
323         struct list_head *node;
324         unsigned long flags;
325
326         spin_lock_irqsave(&gameport_event_lock, flags);
327
328         if (list_empty(&gameport_event_list)) {
329                 spin_unlock_irqrestore(&gameport_event_lock, flags);
330                 return NULL;
331         }
332
333         node = gameport_event_list.next;
334         event = list_entry(node, struct gameport_event, node);
335         list_del_init(node);
336
337         spin_unlock_irqrestore(&gameport_event_lock, flags);
338
339         return event;
340 }
341
342 static void gameport_handle_events(void)
343 {
344         struct gameport_event *event;
345         struct gameport_driver *gameport_drv;
346
347         down(&gameport_sem);
348
349         while ((event = gameport_get_event())) {
350
351                 switch (event->type) {
352                         case GAMEPORT_REGISTER_PORT:
353                                 gameport_add_port(event->object);
354                                 break;
355
356                         case GAMEPORT_RECONNECT:
357                                 gameport_reconnect_port(event->object);
358                                 break;
359
360                         case GAMEPORT_RESCAN:
361                                 gameport_disconnect_port(event->object);
362                                 gameport_find_driver(event->object);
363                                 break;
364
365                         case GAMEPORT_REGISTER_DRIVER:
366                                 gameport_drv = event->object;
367                                 driver_register(&gameport_drv->driver);
368                                 break;
369
370                         default:
371                                 break;
372                 }
373
374                 gameport_remove_duplicate_events(event);
375                 gameport_free_event(event);
376         }
377
378         up(&gameport_sem);
379 }
380
381 /*
382  * Remove all events that have been submitted for a given gameport port.
383  */
384 static void gameport_remove_pending_events(struct gameport *gameport)
385 {
386         struct list_head *node, *next;
387         struct gameport_event *event;
388         unsigned long flags;
389
390         spin_lock_irqsave(&gameport_event_lock, flags);
391
392         list_for_each_safe(node, next, &gameport_event_list) {
393                 event = list_entry(node, struct gameport_event, node);
394                 if (event->object == gameport) {
395                         list_del_init(node);
396                         gameport_free_event(event);
397                 }
398         }
399
400         spin_unlock_irqrestore(&gameport_event_lock, flags);
401 }
402
403 /*
404  * Destroy child gameport port (if any) that has not been fully registered yet.
405  *
406  * Note that we rely on the fact that port can have only one child and therefore
407  * only one child registration request can be pending. Additionally, children
408  * are registered by driver's connect() handler so there can't be a grandchild
409  * pending registration together with a child.
410  */
411 static struct gameport *gameport_get_pending_child(struct gameport *parent)
412 {
413         struct gameport_event *event;
414         struct gameport *gameport, *child = NULL;
415         unsigned long flags;
416
417         spin_lock_irqsave(&gameport_event_lock, flags);
418
419         list_for_each_entry(event, &gameport_event_list, node) {
420                 if (event->type == GAMEPORT_REGISTER_PORT) {
421                         gameport = event->object;
422                         if (gameport->parent == parent) {
423                                 child = gameport;
424                                 break;
425                         }
426                 }
427         }
428
429         spin_unlock_irqrestore(&gameport_event_lock, flags);
430         return child;
431 }
432
433 static int gameport_thread(void *nothing)
434 {
435         lock_kernel();
436         daemonize("kgameportd");
437         allow_signal(SIGTERM);
438
439         do {
440                 gameport_handle_events();
441                 wait_event_interruptible(gameport_wait, !list_empty(&gameport_event_list));
442                 try_to_freeze(PF_FREEZE);
443         } while (!signal_pending(current));
444
445         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
446
447         unlock_kernel();
448         complete_and_exit(&gameport_exited, 0);
449 }
450
451
452 /*
453  * Gameport port operations
454  */
455
456 static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
457 {
458         struct gameport *gameport = to_gameport_port(dev);
459         return sprintf(buf, "%s\n", gameport->name);
460 }
461
462 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
463 {
464         struct gameport *gameport = to_gameport_port(dev);
465         struct device_driver *drv;
466         int retval;
467
468         retval = down_interruptible(&gameport_sem);
469         if (retval)
470                 return retval;
471
472         retval = count;
473         if (!strncmp(buf, "none", count)) {
474                 gameport_disconnect_port(gameport);
475         } else if (!strncmp(buf, "reconnect", count)) {
476                 gameport_reconnect_port(gameport);
477         } else if (!strncmp(buf, "rescan", count)) {
478                 gameport_disconnect_port(gameport);
479                 gameport_find_driver(gameport);
480         } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
481                 gameport_disconnect_port(gameport);
482                 gameport_bind_driver(gameport, to_gameport_driver(drv));
483                 put_driver(drv);
484         } else {
485                 retval = -EINVAL;
486         }
487
488         up(&gameport_sem);
489
490         return retval;
491 }
492
493 static struct device_attribute gameport_device_attrs[] = {
494         __ATTR(description, S_IRUGO, gameport_show_description, NULL),
495         __ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
496         __ATTR_NULL
497 };
498
499 static void gameport_release_port(struct device *dev)
500 {
501         struct gameport *gameport = to_gameport_port(dev);
502
503         kfree(gameport);
504         module_put(THIS_MODULE);
505 }
506
507 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
508 {
509         va_list args;
510
511         va_start(args, fmt);
512         vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
513         va_end(args);
514 }
515
516 /*
517  * Prepare gameport port for registration.
518  */
519 static void gameport_init_port(struct gameport *gameport)
520 {
521         static atomic_t gameport_no = ATOMIC_INIT(0);
522
523         __module_get(THIS_MODULE);
524
525         init_MUTEX(&gameport->drv_sem);
526         device_initialize(&gameport->dev);
527         snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
528                  "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
529         gameport->dev.bus = &gameport_bus;
530         gameport->dev.release = gameport_release_port;
531         if (gameport->parent)
532                 gameport->dev.parent = &gameport->parent->dev;
533
534         spin_lock_init(&gameport->timer_lock);
535         init_timer(&gameport->poll_timer);
536         gameport->poll_timer.function = gameport_run_poll_handler;
537         gameport->poll_timer.data = (unsigned long)gameport;
538 }
539
540 /*
541  * Complete gameport port registration.
542  * Driver core will attempt to find appropriate driver for the port.
543  */
544 static void gameport_add_port(struct gameport *gameport)
545 {
546         if (gameport->parent)
547                 gameport->parent->child = gameport;
548
549         gameport->speed = gameport_measure_speed(gameport);
550
551         list_add_tail(&gameport->node, &gameport_list);
552
553         if (gameport->io)
554                 printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
555                         gameport->name, gameport->phys, gameport->io, gameport->speed);
556         else
557                 printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
558                         gameport->name, gameport->phys, gameport->speed);
559
560         device_add(&gameport->dev);
561         gameport->registered = 1;
562 }
563
564 /*
565  * gameport_destroy_port() completes deregistration process and removes
566  * port from the system
567  */
568 static void gameport_destroy_port(struct gameport *gameport)
569 {
570         struct gameport *child;
571
572         child = gameport_get_pending_child(gameport);
573         if (child) {
574                 gameport_remove_pending_events(child);
575                 put_device(&child->dev);
576         }
577
578         if (gameport->parent) {
579                 gameport->parent->child = NULL;
580                 gameport->parent = NULL;
581         }
582
583         if (gameport->registered) {
584                 device_del(&gameport->dev);
585                 list_del_init(&gameport->node);
586                 gameport->registered = 0;
587         }
588
589         gameport_remove_pending_events(gameport);
590         put_device(&gameport->dev);
591 }
592
593 /*
594  * Reconnect gameport port and all its children (re-initialize attached devices)
595  */
596 static void gameport_reconnect_port(struct gameport *gameport)
597 {
598         do {
599                 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
600                         gameport_disconnect_port(gameport);
601                         gameport_find_driver(gameport);
602                         /* Ok, old children are now gone, we are done */
603                         break;
604                 }
605                 gameport = gameport->child;
606         } while (gameport);
607 }
608
609 /*
610  * gameport_disconnect_port() unbinds a port from its driver. As a side effect
611  * all child ports are unbound and destroyed.
612  */
613 static void gameport_disconnect_port(struct gameport *gameport)
614 {
615         struct gameport *s, *parent;
616
617         if (gameport->child) {
618                 /*
619                  * Children ports should be disconnected and destroyed
620                  * first, staring with the leaf one, since we don't want
621                  * to do recursion
622                  */
623                 for (s = gameport; s->child; s = s->child)
624                         /* empty */;
625
626                 do {
627                         parent = s->parent;
628
629                         gameport_release_driver(s);
630                         gameport_destroy_port(s);
631                 } while ((s = parent) != gameport);
632         }
633
634         /*
635          * Ok, no children left, now disconnect this port
636          */
637         gameport_release_driver(gameport);
638 }
639
640 void gameport_rescan(struct gameport *gameport)
641 {
642         gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
643 }
644
645 void gameport_reconnect(struct gameport *gameport)
646 {
647         gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
648 }
649
650 /*
651  * Submits register request to kgameportd for subsequent execution.
652  * Note that port registration is always asynchronous.
653  */
654 void __gameport_register_port(struct gameport *gameport, struct module *owner)
655 {
656         gameport_init_port(gameport);
657         gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
658 }
659
660 /*
661  * Synchronously unregisters gameport port.
662  */
663 void gameport_unregister_port(struct gameport *gameport)
664 {
665         down(&gameport_sem);
666         gameport_disconnect_port(gameport);
667         gameport_destroy_port(gameport);
668         up(&gameport_sem);
669 }
670
671
672 /*
673  * Gameport driver operations
674  */
675
676 static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
677 {
678         struct gameport_driver *driver = to_gameport_driver(drv);
679         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
680 }
681
682 static struct driver_attribute gameport_driver_attrs[] = {
683         __ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
684         __ATTR_NULL
685 };
686
687 static int gameport_driver_probe(struct device *dev)
688 {
689         struct gameport *gameport = to_gameport_port(dev);
690         struct gameport_driver *drv = to_gameport_driver(dev->driver);
691
692         drv->connect(gameport, drv);
693         return gameport->drv ? 0 : -ENODEV;
694 }
695
696 static int gameport_driver_remove(struct device *dev)
697 {
698         struct gameport *gameport = to_gameport_port(dev);
699         struct gameport_driver *drv = to_gameport_driver(dev->driver);
700
701         drv->disconnect(gameport);
702         return 0;
703 }
704
705 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
706 {
707         drv->driver.bus = &gameport_bus;
708         drv->driver.probe = gameport_driver_probe;
709         drv->driver.remove = gameport_driver_remove;
710         gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
711 }
712
713 void gameport_unregister_driver(struct gameport_driver *drv)
714 {
715         struct gameport *gameport;
716
717         down(&gameport_sem);
718         drv->ignore = 1;        /* so gameport_find_driver ignores it */
719
720 start_over:
721         list_for_each_entry(gameport, &gameport_list, node) {
722                 if (gameport->drv == drv) {
723                         gameport_disconnect_port(gameport);
724                         gameport_find_driver(gameport);
725                         /* we could've deleted some ports, restart */
726                         goto start_over;
727                 }
728         }
729
730         driver_unregister(&drv->driver);
731         up(&gameport_sem);
732 }
733
734 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
735 {
736         struct gameport_driver *gameport_drv = to_gameport_driver(drv);
737
738         return !gameport_drv->ignore;
739 }
740
741 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
742 {
743         down(&gameport->drv_sem);
744         gameport->drv = drv;
745         up(&gameport->drv_sem);
746 }
747
748 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
749 {
750
751         if (gameport->open) {
752                 if (gameport->open(gameport, mode)) {
753                         return -1;
754                 }
755         } else {
756                 if (mode != GAMEPORT_MODE_RAW)
757                         return -1;
758         }
759
760         gameport_set_drv(gameport, drv);
761         return 0;
762 }
763
764 void gameport_close(struct gameport *gameport)
765 {
766         del_timer_sync(&gameport->poll_timer);
767         gameport->poll_handler = NULL;
768         gameport->poll_interval = 0;
769         gameport_set_drv(gameport, NULL);
770         if (gameport->close)
771                 gameport->close(gameport);
772 }
773
774 static int __init gameport_init(void)
775 {
776         if (!(gameport_pid = kernel_thread(gameport_thread, NULL, CLONE_KERNEL))) {
777                 printk(KERN_ERR "gameport: Failed to start kgameportd\n");
778                 return -1;
779         }
780
781         gameport_bus.dev_attrs = gameport_device_attrs;
782         gameport_bus.drv_attrs = gameport_driver_attrs;
783         gameport_bus.match = gameport_bus_match;
784         bus_register(&gameport_bus);
785
786         return 0;
787 }
788
789 static void __exit gameport_exit(void)
790 {
791         bus_unregister(&gameport_bus);
792         kill_proc(gameport_pid, SIGTERM, 1);
793         wait_for_completion(&gameport_exited);
794 }
795
796 module_init(gameport_init);
797 module_exit(gameport_exit);