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