xref: /linux/drivers/input/input.c (revision 2624f124b3b5d550ab2fbef7ee3bc0e1fed09722)
1 /*
2  * The input core
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  */
6 
7 /*
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published by
10  * the Free Software Foundation.
11  */
12 
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/smp_lock.h>
16 #include <linux/input.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/major.h>
20 #include <linux/proc_fs.h>
21 #include <linux/kobject_uevent.h>
22 #include <linux/interrupt.h>
23 #include <linux/poll.h>
24 #include <linux/device.h>
25 #include <linux/devfs_fs_kernel.h>
26 
27 MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
28 MODULE_DESCRIPTION("Input core");
29 MODULE_LICENSE("GPL");
30 
31 EXPORT_SYMBOL(input_register_device);
32 EXPORT_SYMBOL(input_unregister_device);
33 EXPORT_SYMBOL(input_register_handler);
34 EXPORT_SYMBOL(input_unregister_handler);
35 EXPORT_SYMBOL(input_grab_device);
36 EXPORT_SYMBOL(input_release_device);
37 EXPORT_SYMBOL(input_open_device);
38 EXPORT_SYMBOL(input_close_device);
39 EXPORT_SYMBOL(input_accept_process);
40 EXPORT_SYMBOL(input_flush_device);
41 EXPORT_SYMBOL(input_event);
42 EXPORT_SYMBOL(input_class);
43 
44 #define INPUT_DEVICES	256
45 
46 static LIST_HEAD(input_dev_list);
47 static LIST_HEAD(input_handler_list);
48 
49 static struct input_handler *input_table[8];
50 
51 void input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
52 {
53 	struct input_handle *handle;
54 
55 	if (type > EV_MAX || !test_bit(type, dev->evbit))
56 		return;
57 
58 	add_input_randomness(type, code, value);
59 
60 	switch (type) {
61 
62 		case EV_SYN:
63 			switch (code) {
64 				case SYN_CONFIG:
65 					if (dev->event) dev->event(dev, type, code, value);
66 					break;
67 
68 				case SYN_REPORT:
69 					if (dev->sync) return;
70 					dev->sync = 1;
71 					break;
72 			}
73 			break;
74 
75 		case EV_KEY:
76 
77 			if (code > KEY_MAX || !test_bit(code, dev->keybit) || !!test_bit(code, dev->key) == value)
78 				return;
79 
80 			if (value == 2)
81 				break;
82 
83 			change_bit(code, dev->key);
84 
85 			if (test_bit(EV_REP, dev->evbit) && dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] && dev->timer.data && value) {
86 				dev->repeat_key = code;
87 				mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
88 			}
89 
90 			break;
91 
92 		case EV_SW:
93 
94 			if (code > SW_MAX || !test_bit(code, dev->swbit) || !!test_bit(code, dev->sw) == value)
95 				return;
96 
97 			change_bit(code, dev->sw);
98 
99 			break;
100 
101 		case EV_ABS:
102 
103 			if (code > ABS_MAX || !test_bit(code, dev->absbit))
104 				return;
105 
106 			if (dev->absfuzz[code]) {
107 				if ((value > dev->abs[code] - (dev->absfuzz[code] >> 1)) &&
108 				    (value < dev->abs[code] + (dev->absfuzz[code] >> 1)))
109 					return;
110 
111 				if ((value > dev->abs[code] - dev->absfuzz[code]) &&
112 				    (value < dev->abs[code] + dev->absfuzz[code]))
113 					value = (dev->abs[code] * 3 + value) >> 2;
114 
115 				if ((value > dev->abs[code] - (dev->absfuzz[code] << 1)) &&
116 				    (value < dev->abs[code] + (dev->absfuzz[code] << 1)))
117 					value = (dev->abs[code] + value) >> 1;
118 			}
119 
120 			if (dev->abs[code] == value)
121 				return;
122 
123 			dev->abs[code] = value;
124 			break;
125 
126 		case EV_REL:
127 
128 			if (code > REL_MAX || !test_bit(code, dev->relbit) || (value == 0))
129 				return;
130 
131 			break;
132 
133 		case EV_MSC:
134 
135 			if (code > MSC_MAX || !test_bit(code, dev->mscbit))
136 				return;
137 
138 			if (dev->event) dev->event(dev, type, code, value);
139 
140 			break;
141 
142 		case EV_LED:
143 
144 			if (code > LED_MAX || !test_bit(code, dev->ledbit) || !!test_bit(code, dev->led) == value)
145 				return;
146 
147 			change_bit(code, dev->led);
148 			if (dev->event) dev->event(dev, type, code, value);
149 
150 			break;
151 
152 		case EV_SND:
153 
154 			if (code > SND_MAX || !test_bit(code, dev->sndbit))
155 				return;
156 
157 			if (dev->event) dev->event(dev, type, code, value);
158 
159 			break;
160 
161 		case EV_REP:
162 
163 			if (code > REP_MAX || value < 0 || dev->rep[code] == value) return;
164 
165 			dev->rep[code] = value;
166 			if (dev->event) dev->event(dev, type, code, value);
167 
168 			break;
169 
170 		case EV_FF:
171 			if (dev->event) dev->event(dev, type, code, value);
172 			break;
173 	}
174 
175 	if (type != EV_SYN)
176 		dev->sync = 0;
177 
178 	if (dev->grab)
179 		dev->grab->handler->event(dev->grab, type, code, value);
180 	else
181 		list_for_each_entry(handle, &dev->h_list, d_node)
182 			if (handle->open)
183 				handle->handler->event(handle, type, code, value);
184 }
185 
186 static void input_repeat_key(unsigned long data)
187 {
188 	struct input_dev *dev = (void *) data;
189 
190 	if (!test_bit(dev->repeat_key, dev->key))
191 		return;
192 
193 	input_event(dev, EV_KEY, dev->repeat_key, 2);
194 	input_sync(dev);
195 
196 	if (dev->rep[REP_PERIOD])
197 		mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->rep[REP_PERIOD]));
198 }
199 
200 int input_accept_process(struct input_handle *handle, struct file *file)
201 {
202 	if (handle->dev->accept)
203 		return handle->dev->accept(handle->dev, file);
204 
205 	return 0;
206 }
207 
208 int input_grab_device(struct input_handle *handle)
209 {
210 	if (handle->dev->grab)
211 		return -EBUSY;
212 
213 	handle->dev->grab = handle;
214 	return 0;
215 }
216 
217 void input_release_device(struct input_handle *handle)
218 {
219 	if (handle->dev->grab == handle)
220 		handle->dev->grab = NULL;
221 }
222 
223 int input_open_device(struct input_handle *handle)
224 {
225 	struct input_dev *dev = handle->dev;
226 	int err;
227 
228 	err = down_interruptible(&dev->sem);
229 	if (err)
230 		return err;
231 
232 	handle->open++;
233 
234 	if (!dev->users++ && dev->open)
235 		err = dev->open(dev);
236 
237 	if (err)
238 		handle->open--;
239 
240 	up(&dev->sem);
241 
242 	return err;
243 }
244 
245 int input_flush_device(struct input_handle* handle, struct file* file)
246 {
247 	if (handle->dev->flush)
248 		return handle->dev->flush(handle->dev, file);
249 
250 	return 0;
251 }
252 
253 void input_close_device(struct input_handle *handle)
254 {
255 	struct input_dev *dev = handle->dev;
256 
257 	input_release_device(handle);
258 
259 	down(&dev->sem);
260 
261 	if (!--dev->users && dev->close)
262 		dev->close(dev);
263 	handle->open--;
264 
265 	up(&dev->sem);
266 }
267 
268 static void input_link_handle(struct input_handle *handle)
269 {
270 	list_add_tail(&handle->d_node, &handle->dev->h_list);
271 	list_add_tail(&handle->h_node, &handle->handler->h_list);
272 }
273 
274 #define MATCH_BIT(bit, max) \
275 		for (i = 0; i < NBITS(max); i++) \
276 			if ((id->bit[i] & dev->bit[i]) != id->bit[i]) \
277 				break; \
278 		if (i != NBITS(max)) \
279 			continue;
280 
281 static struct input_device_id *input_match_device(struct input_device_id *id, struct input_dev *dev)
282 {
283 	int i;
284 
285 	for (; id->flags || id->driver_info; id++) {
286 
287 		if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
288 			if (id->id.bustype != dev->id.bustype)
289 				continue;
290 
291 		if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
292 			if (id->id.vendor != dev->id.vendor)
293 				continue;
294 
295 		if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
296 			if (id->id.product != dev->id.product)
297 				continue;
298 
299 		if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
300 			if (id->id.version != dev->id.version)
301 				continue;
302 
303 		MATCH_BIT(evbit,  EV_MAX);
304 		MATCH_BIT(keybit, KEY_MAX);
305 		MATCH_BIT(relbit, REL_MAX);
306 		MATCH_BIT(absbit, ABS_MAX);
307 		MATCH_BIT(mscbit, MSC_MAX);
308 		MATCH_BIT(ledbit, LED_MAX);
309 		MATCH_BIT(sndbit, SND_MAX);
310 		MATCH_BIT(ffbit,  FF_MAX);
311 
312 		return id;
313 	}
314 
315 	return NULL;
316 }
317 
318 
319 /*
320  * Input hotplugging interface - loading event handlers based on
321  * device bitfields.
322  */
323 
324 #ifdef CONFIG_HOTPLUG
325 
326 /*
327  * Input hotplugging invokes what /proc/sys/kernel/hotplug says
328  * (normally /sbin/hotplug) when input devices get added or removed.
329  *
330  * This invokes a user mode policy agent, typically helping to load driver
331  * or other modules, configure the device, and more.  Drivers can provide
332  * a MODULE_DEVICE_TABLE to help with module loading subtasks.
333  *
334  */
335 
336 #define SPRINTF_BIT_A(bit, name, max) \
337 	do { \
338 		envp[i++] = scratch; \
339 		scratch += sprintf(scratch, name); \
340 		for (j = NBITS(max) - 1; j >= 0; j--) \
341 			if (dev->bit[j]) break; \
342 		for (; j >= 0; j--) \
343 			scratch += sprintf(scratch, "%lx ", dev->bit[j]); \
344 		scratch++; \
345 	} while (0)
346 
347 #define SPRINTF_BIT_A2(bit, name, max, ev) \
348 	do { \
349 		if (test_bit(ev, dev->evbit)) \
350 			SPRINTF_BIT_A(bit, name, max); \
351 	} while (0)
352 
353 static void input_call_hotplug(char *verb, struct input_dev *dev)
354 {
355 	char *argv[3], **envp, *buf, *scratch;
356 	int i = 0, j, value;
357 
358 	if (!hotplug_path[0]) {
359 		printk(KERN_ERR "input.c: calling hotplug without a hotplug agent defined\n");
360 		return;
361 	}
362 	if (in_interrupt()) {
363 		printk(KERN_ERR "input.c: calling hotplug from interrupt\n");
364 		return;
365 	}
366 	if (!current->fs->root) {
367 		printk(KERN_WARNING "input.c: calling hotplug without valid filesystem\n");
368 		return;
369 	}
370 	if (!(envp = (char **) kmalloc(20 * sizeof(char *), GFP_KERNEL))) {
371 		printk(KERN_ERR "input.c: not enough memory allocating hotplug environment\n");
372 		return;
373 	}
374 	if (!(buf = kmalloc(1024, GFP_KERNEL))) {
375 		kfree (envp);
376 		printk(KERN_ERR "input.c: not enough memory allocating hotplug environment\n");
377 		return;
378 	}
379 
380 	argv[0] = hotplug_path;
381 	argv[1] = "input";
382 	argv[2] = NULL;
383 
384 	envp[i++] = "HOME=/";
385 	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
386 
387 	scratch = buf;
388 
389 	envp[i++] = scratch;
390 	scratch += sprintf(scratch, "ACTION=%s", verb) + 1;
391 
392 	envp[i++] = scratch;
393 	scratch += sprintf(scratch, "PRODUCT=%x/%x/%x/%x",
394 		dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version) + 1;
395 
396 	if (dev->name) {
397 		envp[i++] = scratch;
398 		scratch += sprintf(scratch, "NAME=%s", dev->name) + 1;
399 	}
400 
401 	if (dev->phys) {
402 		envp[i++] = scratch;
403 		scratch += sprintf(scratch, "PHYS=%s", dev->phys) + 1;
404 	}
405 
406 	SPRINTF_BIT_A(evbit, "EV=", EV_MAX);
407 	SPRINTF_BIT_A2(keybit, "KEY=", KEY_MAX, EV_KEY);
408 	SPRINTF_BIT_A2(relbit, "REL=", REL_MAX, EV_REL);
409 	SPRINTF_BIT_A2(absbit, "ABS=", ABS_MAX, EV_ABS);
410 	SPRINTF_BIT_A2(mscbit, "MSC=", MSC_MAX, EV_MSC);
411 	SPRINTF_BIT_A2(ledbit, "LED=", LED_MAX, EV_LED);
412 	SPRINTF_BIT_A2(sndbit, "SND=", SND_MAX, EV_SND);
413 	SPRINTF_BIT_A2(ffbit,  "FF=",  FF_MAX, EV_FF);
414 	SPRINTF_BIT_A2(swbit,  "SW=",  SW_MAX, EV_SW);
415 
416 	envp[i++] = NULL;
417 
418 #ifdef INPUT_DEBUG
419 	printk(KERN_DEBUG "input.c: calling %s %s [%s %s %s %s %s]\n",
420 		argv[0], argv[1], envp[0], envp[1], envp[2], envp[3], envp[4]);
421 #endif
422 
423 	value = call_usermodehelper(argv [0], argv, envp, 0);
424 
425 	kfree(buf);
426 	kfree(envp);
427 
428 #ifdef INPUT_DEBUG
429 	if (value != 0)
430 		printk(KERN_DEBUG "input.c: hotplug returned %d\n", value);
431 #endif
432 }
433 
434 #endif
435 
436 #ifdef CONFIG_PROC_FS
437 
438 static struct proc_dir_entry *proc_bus_input_dir;
439 static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
440 static int input_devices_state;
441 
442 static inline void input_wakeup_procfs_readers(void)
443 {
444 	input_devices_state++;
445 	wake_up(&input_devices_poll_wait);
446 }
447 
448 static unsigned int input_devices_poll(struct file *file, poll_table *wait)
449 {
450 	int state = input_devices_state;
451 	poll_wait(file, &input_devices_poll_wait, wait);
452 	if (state != input_devices_state)
453 		return POLLIN | POLLRDNORM;
454 	return 0;
455 }
456 
457 #define SPRINTF_BIT_B(bit, name, max) \
458 	do { \
459 		len += sprintf(buf + len, "B: %s", name); \
460 		for (i = NBITS(max) - 1; i >= 0; i--) \
461 			if (dev->bit[i]) break; \
462 		for (; i >= 0; i--) \
463 			len += sprintf(buf + len, "%lx ", dev->bit[i]); \
464 		len += sprintf(buf + len, "\n"); \
465 	} while (0)
466 
467 #define SPRINTF_BIT_B2(bit, name, max, ev) \
468 	do { \
469 		if (test_bit(ev, dev->evbit)) \
470 			SPRINTF_BIT_B(bit, name, max); \
471 	} while (0)
472 
473 static int input_devices_read(char *buf, char **start, off_t pos, int count, int *eof, void *data)
474 {
475 	struct input_dev *dev;
476 	struct input_handle *handle;
477 
478 	off_t at = 0;
479 	int i, len, cnt = 0;
480 
481 	list_for_each_entry(dev, &input_dev_list, node) {
482 
483 		len = sprintf(buf, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
484 			dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
485 
486 		len += sprintf(buf + len, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
487 		len += sprintf(buf + len, "P: Phys=%s\n", dev->phys ? dev->phys : "");
488 		len += sprintf(buf + len, "H: Handlers=");
489 
490 		list_for_each_entry(handle, &dev->h_list, d_node)
491 			len += sprintf(buf + len, "%s ", handle->name);
492 
493 		len += sprintf(buf + len, "\n");
494 
495 		SPRINTF_BIT_B(evbit, "EV=", EV_MAX);
496 		SPRINTF_BIT_B2(keybit, "KEY=", KEY_MAX, EV_KEY);
497 		SPRINTF_BIT_B2(relbit, "REL=", REL_MAX, EV_REL);
498 		SPRINTF_BIT_B2(absbit, "ABS=", ABS_MAX, EV_ABS);
499 		SPRINTF_BIT_B2(mscbit, "MSC=", MSC_MAX, EV_MSC);
500 		SPRINTF_BIT_B2(ledbit, "LED=", LED_MAX, EV_LED);
501 		SPRINTF_BIT_B2(sndbit, "SND=", SND_MAX, EV_SND);
502 		SPRINTF_BIT_B2(ffbit,  "FF=",  FF_MAX, EV_FF);
503 		SPRINTF_BIT_B2(swbit,  "SW=",  SW_MAX, EV_SW);
504 
505 		len += sprintf(buf + len, "\n");
506 
507 		at += len;
508 
509 		if (at >= pos) {
510 			if (!*start) {
511 				*start = buf + (pos - (at - len));
512 				cnt = at - pos;
513 			} else  cnt += len;
514 			buf += len;
515 			if (cnt >= count)
516 				break;
517 		}
518 	}
519 
520 	if (&dev->node == &input_dev_list)
521 		*eof = 1;
522 
523 	return (count > cnt) ? cnt : count;
524 }
525 
526 static int input_handlers_read(char *buf, char **start, off_t pos, int count, int *eof, void *data)
527 {
528 	struct input_handler *handler;
529 
530 	off_t at = 0;
531 	int len = 0, cnt = 0;
532 	int i = 0;
533 
534 	list_for_each_entry(handler, &input_handler_list, node) {
535 
536 		if (handler->fops)
537 			len = sprintf(buf, "N: Number=%d Name=%s Minor=%d\n",
538 				i++, handler->name, handler->minor);
539 		else
540 			len = sprintf(buf, "N: Number=%d Name=%s\n",
541 				i++, handler->name);
542 
543 		at += len;
544 
545 		if (at >= pos) {
546 			if (!*start) {
547 				*start = buf + (pos - (at - len));
548 				cnt = at - pos;
549 			} else  cnt += len;
550 			buf += len;
551 			if (cnt >= count)
552 				break;
553 		}
554 	}
555 	if (&handler->node == &input_handler_list)
556 		*eof = 1;
557 
558 	return (count > cnt) ? cnt : count;
559 }
560 
561 static struct file_operations input_fileops;
562 
563 static int __init input_proc_init(void)
564 {
565 	struct proc_dir_entry *entry;
566 
567 	proc_bus_input_dir = proc_mkdir("input", proc_bus);
568 	if (!proc_bus_input_dir)
569 		return -ENOMEM;
570 
571 	proc_bus_input_dir->owner = THIS_MODULE;
572 
573 	entry = create_proc_read_entry("devices", 0, proc_bus_input_dir, input_devices_read, NULL);
574 	if (!entry)
575 		goto fail1;
576 
577 	entry->owner = THIS_MODULE;
578 	input_fileops = *entry->proc_fops;
579 	entry->proc_fops = &input_fileops;
580 	entry->proc_fops->poll = input_devices_poll;
581 
582 	entry = create_proc_read_entry("handlers", 0, proc_bus_input_dir, input_handlers_read, NULL);
583 	if (!entry)
584 		goto fail2;
585 
586 	entry->owner = THIS_MODULE;
587 
588 	return 0;
589 
590  fail2:	remove_proc_entry("devices", proc_bus_input_dir);
591  fail1: remove_proc_entry("input", proc_bus);
592 	return -ENOMEM;
593 }
594 
595 static void input_proc_exit(void)
596 {
597 	remove_proc_entry("devices", proc_bus_input_dir);
598 	remove_proc_entry("handlers", proc_bus_input_dir);
599 	remove_proc_entry("input", proc_bus);
600 }
601 
602 #else /* !CONFIG_PROC_FS */
603 static inline void input_wakeup_procfs_readers(void) { }
604 static inline int input_proc_init(void) { return 0; }
605 static inline void input_proc_exit(void) { }
606 #endif
607 
608 void input_register_device(struct input_dev *dev)
609 {
610 	struct input_handle *handle;
611 	struct input_handler *handler;
612 	struct input_device_id *id;
613 
614 	set_bit(EV_SYN, dev->evbit);
615 
616 	init_MUTEX(&dev->sem);
617 
618 	/*
619 	 * If delay and period are pre-set by the driver, then autorepeating
620 	 * is handled by the driver itself and we don't do it in input.c.
621 	 */
622 
623 	init_timer(&dev->timer);
624 	if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
625 		dev->timer.data = (long) dev;
626 		dev->timer.function = input_repeat_key;
627 		dev->rep[REP_DELAY] = 250;
628 		dev->rep[REP_PERIOD] = 33;
629 	}
630 
631 	INIT_LIST_HEAD(&dev->h_list);
632 	list_add_tail(&dev->node, &input_dev_list);
633 
634 	list_for_each_entry(handler, &input_handler_list, node)
635 		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))
636 			if ((id = input_match_device(handler->id_table, dev)))
637 				if ((handle = handler->connect(handler, dev, id)))
638 					input_link_handle(handle);
639 
640 #ifdef CONFIG_HOTPLUG
641 	input_call_hotplug("add", dev);
642 #endif
643 
644 	input_wakeup_procfs_readers();
645 }
646 
647 void input_unregister_device(struct input_dev *dev)
648 {
649 	struct list_head * node, * next;
650 
651 	if (!dev) return;
652 
653 	del_timer_sync(&dev->timer);
654 
655 	list_for_each_safe(node, next, &dev->h_list) {
656 		struct input_handle * handle = to_handle(node);
657 		list_del_init(&handle->d_node);
658 		list_del_init(&handle->h_node);
659 		handle->handler->disconnect(handle);
660 	}
661 
662 #ifdef CONFIG_HOTPLUG
663 	input_call_hotplug("remove", dev);
664 #endif
665 
666 	list_del_init(&dev->node);
667 
668 	input_wakeup_procfs_readers();
669 }
670 
671 void input_register_handler(struct input_handler *handler)
672 {
673 	struct input_dev *dev;
674 	struct input_handle *handle;
675 	struct input_device_id *id;
676 
677 	if (!handler) return;
678 
679 	INIT_LIST_HEAD(&handler->h_list);
680 
681 	if (handler->fops != NULL)
682 		input_table[handler->minor >> 5] = handler;
683 
684 	list_add_tail(&handler->node, &input_handler_list);
685 
686 	list_for_each_entry(dev, &input_dev_list, node)
687 		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))
688 			if ((id = input_match_device(handler->id_table, dev)))
689 				if ((handle = handler->connect(handler, dev, id)))
690 					input_link_handle(handle);
691 
692 	input_wakeup_procfs_readers();
693 }
694 
695 void input_unregister_handler(struct input_handler *handler)
696 {
697 	struct list_head * node, * next;
698 
699 	list_for_each_safe(node, next, &handler->h_list) {
700 		struct input_handle * handle = to_handle_h(node);
701 		list_del_init(&handle->h_node);
702 		list_del_init(&handle->d_node);
703 		handler->disconnect(handle);
704 	}
705 
706 	list_del_init(&handler->node);
707 
708 	if (handler->fops != NULL)
709 		input_table[handler->minor >> 5] = NULL;
710 
711 	input_wakeup_procfs_readers();
712 }
713 
714 static int input_open_file(struct inode *inode, struct file *file)
715 {
716 	struct input_handler *handler = input_table[iminor(inode) >> 5];
717 	struct file_operations *old_fops, *new_fops = NULL;
718 	int err;
719 
720 	/* No load-on-demand here? */
721 	if (!handler || !(new_fops = fops_get(handler->fops)))
722 		return -ENODEV;
723 
724 	/*
725 	 * That's _really_ odd. Usually NULL ->open means "nothing special",
726 	 * not "no device". Oh, well...
727 	 */
728 	if (!new_fops->open) {
729 		fops_put(new_fops);
730 		return -ENODEV;
731 	}
732 	old_fops = file->f_op;
733 	file->f_op = new_fops;
734 
735 	err = new_fops->open(inode, file);
736 
737 	if (err) {
738 		fops_put(file->f_op);
739 		file->f_op = fops_get(old_fops);
740 	}
741 	fops_put(old_fops);
742 	return err;
743 }
744 
745 static struct file_operations input_fops = {
746 	.owner = THIS_MODULE,
747 	.open = input_open_file,
748 };
749 
750 struct class *input_class;
751 
752 static int __init input_init(void)
753 {
754 	int err;
755 
756 	input_class = class_create(THIS_MODULE, "input");
757 	if (IS_ERR(input_class)) {
758 		printk(KERN_ERR "input: unable to register input class\n");
759 		return PTR_ERR(input_class);
760 	}
761 
762 	err = input_proc_init();
763 	if (err)
764 		goto fail1;
765 
766 	err = register_chrdev(INPUT_MAJOR, "input", &input_fops);
767 	if (err) {
768 		printk(KERN_ERR "input: unable to register char major %d", INPUT_MAJOR);
769 		goto fail2;
770 	}
771 
772 	err = devfs_mk_dir("input");
773 	if (err)
774 		goto fail3;
775 
776 	return 0;
777 
778  fail3:	unregister_chrdev(INPUT_MAJOR, "input");
779  fail2:	input_proc_exit();
780  fail1:	class_destroy(input_class);
781 	return err;
782 }
783 
784 static void __exit input_exit(void)
785 {
786 	input_proc_exit();
787 	devfs_remove("input");
788 	unregister_chrdev(INPUT_MAJOR, "input");
789 	class_destroy(input_class);
790 }
791 
792 subsys_initcall(input_init);
793 module_exit(input_exit);
794