aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/input/gameport/gameport.c
blob: a0af97efe6ac0e23fd440cc1608db170890a005d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
/*
 * Generic gameport layer
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 * Copyright (c) 2005 Dmitry Torokhov
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/gameport.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/sched.h>	/* HZ */
#include <linux/mutex.h>

/*#include <asm/io.h>*/

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Generic gameport layer");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(__gameport_register_port);
EXPORT_SYMBOL(gameport_unregister_port);
EXPORT_SYMBOL(__gameport_register_driver);
EXPORT_SYMBOL(gameport_unregister_driver);
EXPORT_SYMBOL(gameport_open);
EXPORT_SYMBOL(gameport_close);
EXPORT_SYMBOL(gameport_rescan);
EXPORT_SYMBOL(gameport_cooked_read);
EXPORT_SYMBOL(gameport_set_name);
EXPORT_SYMBOL(gameport_set_phys);
EXPORT_SYMBOL(gameport_start_polling);
EXPORT_SYMBOL(gameport_stop_polling);

/*
 * gameport_mutex protects entire gameport subsystem and is taken
 * every time gameport port or driver registrered or unregistered.
 */
static DEFINE_MUTEX(gameport_mutex);

static LIST_HEAD(gameport_list);

static struct bus_type gameport_bus;

static void gameport_add_driver(struct gameport_driver *drv);
static void gameport_add_port(struct gameport *gameport);
static void gameport_destroy_port(struct gameport *gameport);
static void gameport_reconnect_port(struct gameport *gameport);
static void gameport_disconnect_port(struct gameport *gameport);

#if defined(__i386__)

#include <asm/i8253.h>

#define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
#define GET_TIME(x)     do { x = get_time_pit(); } while (0)

static unsigned int get_time_pit(void)
{
	unsigned long flags;
	unsigned int count;

	spin_lock_irqsave(&i8253_lock, flags);
	outb_p(0x00, 0x43);
	count = inb_p(0x40);
	count |= inb_p(0x40) << 8;
	spin_unlock_irqrestore(&i8253_lock, flags);

	return count;
}

#endif



/*
 * gameport_measure_speed() measures the gameport i/o speed.
 */

static int gameport_measure_speed(struct gameport *gameport)
{
#if defined(__i386__)

	unsigned int i, t, t1, t2, t3, tx;
	unsigned long flags;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
		return 0;

	tx = 1 << 30;

	for(i = 0; i < 50; i++) {
		local_irq_save(flags);
		GET_TIME(t1);
		for (t = 0; t < 50; t++) gameport_read(gameport);
		GET_TIME(t2);
		GET_TIME(t3);
		local_irq_restore(flags);
		udelay(i * 10);
		if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
	}

	gameport_close(gameport);
	return 59659 / (tx < 1 ? 1 : tx);

#elif defined (__x86_64__)

	unsigned int i, t;
	unsigned long tx, t1, t2, flags;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
		return 0;

	tx = 1 << 30;

	for(i = 0; i < 50; i++) {
		local_irq_save(flags);
		rdtscl(t1);
		for (t = 0; t < 50; t++) gameport_read(gameport);
		rdtscl(t2);
		local_irq_restore(flags);
		udelay(i * 10);
		if (t2 - t1 < tx) tx = t2 - t1;
	}

	gameport_close(gameport);
	return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);

#else

	unsigned int j, t = 0;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
		return 0;

	j = jiffies; while (j == jiffies);
	j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }

	gameport_close(gameport);
	return t * HZ / 1000;

#endif
}

void gameport_start_polling(struct gameport *gameport)
{
	spin_lock(&gameport->timer_lock);

	if (!gameport->poll_cnt++) {
		BUG_ON(!gameport->poll_handler);
		BUG_ON(!gameport->poll_interval);
		mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
	}

	spin_unlock(&gameport->timer_lock);
}

void gameport_stop_polling(struct gameport *gameport)
{
	spin_lock(&gameport->timer_lock);

	if (!--gameport->poll_cnt)
		del_timer(&gameport->poll_timer);

	spin_unlock(&gameport->timer_lock);
}

static void gameport_run_poll_handler(unsigned long d)
{
	struct gameport *gameport = (struct gameport *)d;

	gameport->poll_handler(gameport);
	if (gameport->poll_cnt)
		mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
}

/*
 * Basic gameport -> driver core mappings
 */

static void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
{
	int error;

	down_write(&gameport_bus.subsys.rwsem);

	gameport->dev.driver = &drv->driver;
	if (drv->connect(gameport, drv)) {
		gameport->dev.driver = NULL;
		goto out;
	}

	error = device_bind_driver(&gameport->dev);
	if (error) {
		printk(KERN_WARNING
			"gameport: device_bind_driver() failed "
			"for %s (%s) and %s, error: %d\n",
			gameport->phys, gameport->name,
			drv->description, error);
		drv->disconnect(gameport);
		gameport->dev.driver = NULL;
		goto out;
	}

 out:
	up_write(&gameport_bus.subsys.rwsem);
}

static void gameport_release_driver(struct gameport *gameport)
{
	down_write(&gameport_bus.subsys.rwsem);
	device_release_driver(&gameport->dev);
	up_write(&gameport_bus.subsys.rwsem);
}

static void gameport_find_driver(struct gameport *gameport)
{
	int error;

	down_write(&gameport_bus.subsys.rwsem);
	error = device_attach(&gameport->dev);
	if (error < 0)
		printk(KERN_WARNING
			"gameport: device_attach() failed for %s (%s), error: %d\n",
			gameport->phys, gameport->name, error);
	up_write(&gameport_bus.subsys.rwsem);
}


/*
 * Gameport event processing.
 */

enum gameport_event_type {
	GAMEPORT_RESCAN,
	GAMEPORT_RECONNECT,
	GAMEPORT_REGISTER_PORT,
	GAMEPORT_REGISTER_DRIVER,
};

struct gameport_event {
	enum gameport_event_type type;
	void *object;
	struct module *owner;
	struct list_head node;
};

static DEFINE_SPINLOCK(gameport_event_lock);	/* protects gameport_event_list */
static LIST_HEAD(gameport_event_list);
static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
static struct task_struct *gameport_task;

static void gameport_queue_event(void *object, struct module *owner,
			      enum gameport_event_type event_type)
{
	unsigned long flags;
	struct gameport_event *event;

	spin_lock_irqsave(&gameport_event_lock, flags);

	/*
	 * Scan event list for the other events for the same gameport port,
	 * starting with the most recent one. If event is the same we
	 * do not need add new one. If event is of different type we
	 * need to add this event and should not look further because
	 * we need to preseve sequence of distinct events.
	 */
	list_for_each_entry_reverse(event, &gameport_event_list, node) {
		if (event->object == object) {
			if (event->type == event_type)
				goto out;
			break;
		}
	}

	if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
		if (!try_module_get(owner)) {
			printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
			kfree(event);
			goto out;
		}

		event->type = event_type;
		event->object = object;
		event->owner = owner;

		list_add_tail(&event->node, &gameport_event_list);
		wake_up(&gameport_wait);
	} else {
		printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
	}
out:
	spin_unlock_irqrestore(&gameport_event_lock, flags);
}

static void gameport_free_event(struct gameport_event *event)
{
	module_put(event->owner);
	kfree(event);
}

static void gameport_remove_duplicate_events(struct gameport_event *event)
{
	struct list_head *node, *next;
	struct gameport_event *e;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_safe(node, next, &gameport_event_list) {
		e = list_entry(node, struct gameport_event, node);
		if (event->object == e->object) {
			/*
			 * If this event is of different type we should not
			 * look further - we only suppress duplicate events
			 * that were sent back-to-back.
			 */
			if (event->type != e->type)
				break;

			list_del_init(node);
			gameport_free_event(e);
		}
	}

	spin_unlock_irqrestore(&gameport_event_lock, flags);
}

static struct gameport_event *gameport_get_event(void)
{
	struct gameport_event *event;
	struct list_head *node;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	if (list_empty(&gameport_event_list)) {
		spin_unlock_irqrestore(&gameport_event_lock, flags);
		return NULL;
	}

	node = gameport_event_list.next;
	event = list_entry(node, struct gameport_event, node);
	list_del_init(node);

	spin_unlock_irqrestore(&gameport_event_lock, flags);

	return event;
}

static void gameport_handle_event(void)
{
	struct gameport_event *event;

	mutex_lock(&gameport_mutex);

	/*
	 * Note that we handle only one event here to give swsusp
	 * a chance to freeze kgameportd thread. Gameport events
	 * should be pretty rare so we are not concerned about
	 * taking performance hit.
	 */
	if ((event = gameport_get_event())) {

		switch (event->type) {
			case GAMEPORT_REGISTER_PORT:
				gameport_add_port(event->object);
				break;

			case GAMEPORT_RECONNECT:
				gameport_reconnect_port(event->object);
				break;

			case GAMEPORT_RESCAN:
				gameport_disconnect_port(event->object);
				gameport_find_driver(event->object);
				break;

			case GAMEPORT_REGISTER_DRIVER:
				gameport_add_driver(event->object);
				break;

			default:
				break;
		}

		gameport_remove_duplicate_events(event);
		gameport_free_event(event);
	}

	mutex_unlock(&gameport_mutex);
}

/*
 * Remove all events that have been submitted for a given gameport port.
 */
static void gameport_remove_pending_events(struct gameport *gameport)
{
	struct list_head *node, *next;
	struct gameport_event *event;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_safe(node, next, &gameport_event_list) {
		event = list_entry(node, struct gameport_event, node);
		if (event->object == gameport) {
			list_del_init(node);
			gameport_free_event(event);
		}
	}

	spin_unlock_irqrestore(&gameport_event_lock, flags);
}

/*
 * Destroy child gameport port (if any) that has not been fully registered yet.
 *
 * Note that we rely on the fact that port can have only one child and therefore
 * only one child registration request can be pending. Additionally, children
 * are registered by driver's connect() handler so there can't be a grandchild
 * pending registration together with a child.
 */
static struct gameport *gameport_get_pending_child(struct gameport *parent)
{
	struct gameport_event *event;
	struct gameport *gameport, *child = NULL;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_entry(event, &gameport_event_list, node) {
		if (event->type == GAMEPORT_REGISTER_PORT) {
			gameport = event->object;
			if (gameport->parent == parent) {
				child = gameport;
				break;
			}
		}
	}

	spin_unlock_irqrestore(&gameport_event_lock, flags);
	return child;
}

static int gameport_thread(void *nothing)
{
	do {
		gameport_handle_event();
		wait_event_interruptible(gameport_wait,
			kthread_should_stop() || !list_empty(&gameport_event_list));
		try_to_freeze();
	} while (!kthread_should_stop());

	printk(KERN_DEBUG "gameport: kgameportd exiting\n");
	return 0;
}


/*
 * Gameport port operations
 */

static ssize_t gameport_show_description(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct gameport *gameport = to_gameport_port(dev);
	return sprintf(buf, "%s\n", gameport->name);
}

static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct gameport *gameport = to_gameport_port(dev);
	struct device_driver *drv;
	int retval;

	retval = mutex_lock_interruptible(&gameport_mutex);
	if (retval)
		return retval;

	retval = count;
	if (!strncmp(buf, "none", count)) {
		gameport_disconnect_port(gameport);
	} else if (!strncmp(buf, "reconnect", count)) {
		gameport_reconnect_port(gameport);
	} else if (!strncmp(buf, "rescan", count)) {
		gameport_disconnect_port(gameport);
		gameport_find_driver(gameport);
	} else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
		gameport_disconnect_port(gameport);
		gameport_bind_driver(gameport, to_gameport_driver(drv));
		put_driver(drv);
	} else {
		retval = -EINVAL;
	}

	mutex_unlock(&gameport_mutex);

	return retval;
}

static struct device_attribute gameport_device_attrs[] = {
	__ATTR(description, S_IRUGO, gameport_show_description, NULL),
	__ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
	__ATTR_NULL
};

static void gameport_release_port(struct device *dev)
{
	struct gameport *gameport = to_gameport_port(dev);

	kfree(gameport);
	module_put(THIS_MODULE);
}

void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
	va_end(args);
}

/*
 * Prepare gameport port for registration.
 */
static void gameport_init_port(struct gameport *gameport)
{
	static atomic_t gameport_no = ATOMIC_INIT(0);

	__module_get(THIS_MODULE);

	mutex_init(&gameport->drv_mutex);
	device_initialize(&gameport->dev);
	snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
		 "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
	gameport->dev.bus = &gameport_bus;
	gameport->dev.release = gameport_release_port;
	if (gameport->parent)
		gameport->dev.parent = &gameport->parent->dev;

	INIT_LIST_HEAD(&gameport->node);
	spin_lock_init(&gameport->timer_lock);
	init_timer(&gameport->poll_timer);
	gameport->poll_timer.function = gameport_run_poll_handler;
	gameport->poll_timer.data = (unsigned long)gameport;
}

/*
 * Complete gameport port registration.
 * Driver core will attempt to find appropriate driver for the port.
 */
static void gameport_add_port(struct gameport *gameport)
{
	int error;

	if (gameport->parent)
		gameport->parent->child = gameport;

	gameport->speed = gameport_measure_speed(gameport);

	list_add_tail(&gameport->node, &gameport_list);

	if (gameport->io)
		printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
			gameport->name, gameport->phys, gameport->io, gameport->speed);
	else
		printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
			gameport->name, gameport->phys, gameport->speed);

	error = device_add(&gameport->dev);
	if (error)
		printk(KERN_ERR
			"gameport: device_add() failed for %s (%s), error: %d\n",
			gameport->phys, gameport->name, error);
	else
		gameport->registered = 1;
}

/*
 * gameport_destroy_port() completes deregistration process and removes
 * port from the system
 */
static void gameport_destroy_port(struct gameport *gameport)
{
	struct gameport *child;

	child = gameport_get_pending_child(gameport);
	if (child) {
		gameport_remove_pending_events(child);
		put_device(&child->dev);
	}

	if (gameport->parent) {
		gameport->parent->child = NULL;
		gameport->parent = NULL;
	}

	if (gameport->registered) {
		device_del(&gameport->dev);
		gameport->registered = 0;
	}

	list_del_init(&gameport->node);

	gameport_remove_pending_events(gameport);
	put_device(&gameport->dev);
}

/*
 * Reconnect gameport port and all its children (re-initialize attached devices)
 */
static void gameport_reconnect_port(struct gameport *gameport)
{
	do {
		if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
			gameport_disconnect_port(gameport);
			gameport_find_driver(gameport);
			/* Ok, old children are now gone, we are done */
			break;
		}
		gameport = gameport->child;
	} while (gameport);
}

/*
 * gameport_disconnect_port() unbinds a port from its driver. As a side effect
 * all child ports are unbound and destroyed.
 */
static void gameport_disconnect_port(struct gameport *gameport)
{
	struct gameport *s, *parent;

	if (gameport->child) {
		/*
		 * Children ports should be disconnected and destroyed
		 * first, staring with the leaf one, since we don't want
		 * to do recursion
		 */
		for (s = gameport; s->child; s = s->child)
			/* empty */;

		do {
			parent = s->parent;

			gameport_release_driver(s);
			gameport_destroy_port(s);
		} while ((s = parent) != gameport);
	}

	/*
	 * Ok, no children left, now disconnect this port
	 */
	gameport_release_driver(gameport);
}

void gameport_rescan(struct gameport *gameport)
{
	gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
}

void gameport_reconnect(struct gameport *gameport)
{
	gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
}

/*
 * Submits register request to kgameportd for subsequent execution.
 * Note that port registration is always asynchronous.
 */
void __gameport_register_port(struct gameport *gameport, struct module *owner)
{
	gameport_init_port(gameport);
	gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
}

/*
 * Synchronously unregisters gameport port.
 */
void gameport_unregister_port(struct gameport *gameport)
{
	mutex_lock(&gameport_mutex);
	gameport_disconnect_port(gameport);
	gameport_destroy_port(gameport);
	mutex_unlock(&gameport_mutex);
}


/*
 * Gameport driver operations
 */

static ssize_t gameport_driver_show_description(struct device_driver *drv, char *buf)
{
	struct gameport_driver *driver = to_gameport_driver(drv);
	return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
}

static struct driver_attribute gameport_driver_attrs[] = {
	__ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
	__ATTR_NULL
};

static int gameport_driver_probe(struct device *dev)
{
	struct gameport *gameport = to_gameport_port(dev);
	struct gameport_driver *drv = to_gameport_driver(dev->driver);

	drv->connect(gameport, drv);
	return gameport->drv ? 0 : -ENODEV;
}

static int gameport_driver_remove(struct device *dev)
{
	struct gameport *gameport = to_gameport_port(dev);
	struct gameport_driver *drv = to_gameport_driver(dev->driver);

	drv->disconnect(gameport);
	return 0;
}

static struct bus_type gameport_bus = {
	.name	= "gameport",
	.probe	= gameport_driver_probe,
	.remove	= gameport_driver_remove,
};

static void gameport_add_driver(struct gameport_driver *drv)
{
	int error;

	error = driver_register(&drv->driver);
	if (error)
		printk(KERN_ERR
			"gameport: driver_register() failed for %s, error: %d\n",
			drv->driver.name, error);
}

void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
{
	drv->driver.bus = &gameport_bus;
	gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
}

void gameport_unregister_driver(struct gameport_driver *drv)
{
	struct gameport *gameport;

	mutex_lock(&gameport_mutex);
	drv->ignore = 1;	/* so gameport_find_driver ignores it */

start_over:
	list_for_each_entry(gameport, &gameport_list, node) {
		if (gameport->drv == drv) {
			gameport_disconnect_port(gameport);
			gameport_find_driver(gameport);
			/* we could've deleted some ports, restart */
			goto start_over;
		}
	}

	driver_unregister(&drv->driver);
	mutex_unlock(&gameport_mutex);
}

static int gameport_bus_match(struct device *dev, struct device_driver *drv)
{
	struct gameport_driver *gameport_drv = to_gameport_driver(drv);

	return !gameport_drv->ignore;
}

static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
{
	mutex_lock(&gameport->drv_mutex);
	gameport->drv = drv;
	mutex_unlock(&gameport->drv_mutex);
}

int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
{

	if (gameport->open) {
		if (gameport->open(gameport, mode)) {
			return -1;
		}
	} else {
		if (mode != GAMEPORT_MODE_RAW)
			return -1;
	}

	gameport_set_drv(gameport, drv);
	return 0;
}

void gameport_close(struct gameport *gameport)
{
	del_timer_sync(&gameport->poll_timer);
	gameport->poll_handler = NULL;
	gameport->poll_interval = 0;
	gameport_set_drv(gameport, NULL);
	if (gameport->close)
		gameport->close(gameport);
}

static int __init gameport_init(void)
{
	int error;

	gameport_bus.dev_attrs = gameport_device_attrs;
	gameport_bus.drv_attrs = gameport_driver_attrs;
	gameport_bus.match = gameport_bus_match;
	error = bus_register(&gameport_bus);
	if (error) {
		printk(KERN_ERR "gameport: failed to register gameport bus, error: %d\n", error);
		return error;
	}

	gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
	if (IS_ERR(gameport_task)) {
		bus_unregister(&gameport_bus);
		error = PTR_ERR(gameport_task);
		printk(KERN_ERR "gameport: Failed to start kgameportd, error: %d\n", error);
		return error;
	}

	return 0;
}

static void __exit gameport_exit(void)
{
	bus_unregister(&gameport_bus);
	kthread_stop(gameport_task);
}

subsys_initcall(gameport_init);
module_exit(gameport_exit);