xref: /linux/drivers/input/joydev.c (revision 5bdef865eb358b6f3760e25e591ae115e9eeddef)
1 /*
2  * Joystick device driver for the input driver suite.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  * Copyright (c) 1999 Colin Van Dyke
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  */
12 
13 #include <asm/io.h>
14 #include <asm/system.h>
15 #include <linux/delay.h>
16 #include <linux/errno.h>
17 #include <linux/joystick.h>
18 #include <linux/input.h>
19 #include <linux/kernel.h>
20 #include <linux/major.h>
21 #include <linux/slab.h>
22 #include <linux/mm.h>
23 #include <linux/miscdevice.h>
24 #include <linux/module.h>
25 #include <linux/poll.h>
26 #include <linux/init.h>
27 #include <linux/device.h>
28 
29 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
30 MODULE_DESCRIPTION("Joystick device interfaces");
31 MODULE_SUPPORTED_DEVICE("input/js");
32 MODULE_LICENSE("GPL");
33 
34 #define JOYDEV_MINOR_BASE	0
35 #define JOYDEV_MINORS		16
36 #define JOYDEV_BUFFER_SIZE	64
37 
38 struct joydev {
39 	int exist;
40 	int open;
41 	int minor;
42 	struct input_handle handle;
43 	wait_queue_head_t wait;
44 	struct list_head client_list;
45 	spinlock_t client_lock; /* protects client_list */
46 	struct mutex mutex;
47 	struct device dev;
48 
49 	struct js_corr corr[ABS_MAX + 1];
50 	struct JS_DATA_SAVE_TYPE glue;
51 	int nabs;
52 	int nkey;
53 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
54 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
55 	__u8 absmap[ABS_MAX + 1];
56 	__u8 abspam[ABS_MAX + 1];
57 	__s16 abs[ABS_MAX + 1];
58 };
59 
60 struct joydev_client {
61 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
62 	int head;
63 	int tail;
64 	int startup;
65 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
66 	struct fasync_struct *fasync;
67 	struct joydev *joydev;
68 	struct list_head node;
69 };
70 
71 static struct joydev *joydev_table[JOYDEV_MINORS];
72 static DEFINE_MUTEX(joydev_table_mutex);
73 
74 static int joydev_correct(int value, struct js_corr *corr)
75 {
76 	switch (corr->type) {
77 
78 	case JS_CORR_NONE:
79 		break;
80 
81 	case JS_CORR_BROKEN:
82 		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
83 			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
84 			((corr->coef[2] * (value - corr->coef[0])) >> 14);
85 		break;
86 
87 	default:
88 		return 0;
89 	}
90 
91 	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
92 }
93 
94 static void joydev_pass_event(struct joydev_client *client,
95 			      struct js_event *event)
96 {
97 	struct joydev *joydev = client->joydev;
98 
99 	/*
100 	 * IRQs already disabled, just acquire the lock
101 	 */
102 	spin_lock(&client->buffer_lock);
103 
104 	client->buffer[client->head] = *event;
105 
106 	if (client->startup == joydev->nabs + joydev->nkey) {
107 		client->head++;
108 		client->head &= JOYDEV_BUFFER_SIZE - 1;
109 		if (client->tail == client->head)
110 			client->startup = 0;
111 	}
112 
113 	spin_unlock(&client->buffer_lock);
114 
115 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
116 }
117 
118 static void joydev_event(struct input_handle *handle,
119 			 unsigned int type, unsigned int code, int value)
120 {
121 	struct joydev *joydev = handle->private;
122 	struct joydev_client *client;
123 	struct js_event event;
124 
125 	switch (type) {
126 
127 	case EV_KEY:
128 		if (code < BTN_MISC || value == 2)
129 			return;
130 		event.type = JS_EVENT_BUTTON;
131 		event.number = joydev->keymap[code - BTN_MISC];
132 		event.value = value;
133 		break;
134 
135 	case EV_ABS:
136 		event.type = JS_EVENT_AXIS;
137 		event.number = joydev->absmap[code];
138 		event.value = joydev_correct(value,
139 					&joydev->corr[event.number]);
140 		if (event.value == joydev->abs[event.number])
141 			return;
142 		joydev->abs[event.number] = event.value;
143 		break;
144 
145 	default:
146 		return;
147 	}
148 
149 	event.time = jiffies_to_msecs(jiffies);
150 
151 	rcu_read_lock();
152 	list_for_each_entry_rcu(client, &joydev->client_list, node)
153 		joydev_pass_event(client, &event);
154 	rcu_read_unlock();
155 
156 	wake_up_interruptible(&joydev->wait);
157 }
158 
159 static int joydev_fasync(int fd, struct file *file, int on)
160 {
161 	struct joydev_client *client = file->private_data;
162 
163 	return fasync_helper(fd, file, on, &client->fasync);
164 }
165 
166 static void joydev_free(struct device *dev)
167 {
168 	struct joydev *joydev = container_of(dev, struct joydev, dev);
169 
170 	input_put_device(joydev->handle.dev);
171 	kfree(joydev);
172 }
173 
174 static void joydev_attach_client(struct joydev *joydev,
175 				 struct joydev_client *client)
176 {
177 	spin_lock(&joydev->client_lock);
178 	list_add_tail_rcu(&client->node, &joydev->client_list);
179 	spin_unlock(&joydev->client_lock);
180 	synchronize_rcu();
181 }
182 
183 static void joydev_detach_client(struct joydev *joydev,
184 				 struct joydev_client *client)
185 {
186 	spin_lock(&joydev->client_lock);
187 	list_del_rcu(&client->node);
188 	spin_unlock(&joydev->client_lock);
189 	synchronize_rcu();
190 }
191 
192 static int joydev_open_device(struct joydev *joydev)
193 {
194 	int retval;
195 
196 	retval = mutex_lock_interruptible(&joydev->mutex);
197 	if (retval)
198 		return retval;
199 
200 	if (!joydev->exist)
201 		retval = -ENODEV;
202 	else if (!joydev->open++) {
203 		retval = input_open_device(&joydev->handle);
204 		if (retval)
205 			joydev->open--;
206 	}
207 
208 	mutex_unlock(&joydev->mutex);
209 	return retval;
210 }
211 
212 static void joydev_close_device(struct joydev *joydev)
213 {
214 	mutex_lock(&joydev->mutex);
215 
216 	if (joydev->exist && !--joydev->open)
217 		input_close_device(&joydev->handle);
218 
219 	mutex_unlock(&joydev->mutex);
220 }
221 
222 /*
223  * Wake up users waiting for IO so they can disconnect from
224  * dead device.
225  */
226 static void joydev_hangup(struct joydev *joydev)
227 {
228 	struct joydev_client *client;
229 
230 	spin_lock(&joydev->client_lock);
231 	list_for_each_entry(client, &joydev->client_list, node)
232 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
233 	spin_unlock(&joydev->client_lock);
234 
235 	wake_up_interruptible(&joydev->wait);
236 }
237 
238 static int joydev_release(struct inode *inode, struct file *file)
239 {
240 	struct joydev_client *client = file->private_data;
241 	struct joydev *joydev = client->joydev;
242 
243 	joydev_detach_client(joydev, client);
244 	kfree(client);
245 
246 	joydev_close_device(joydev);
247 	put_device(&joydev->dev);
248 
249 	return 0;
250 }
251 
252 static int joydev_open(struct inode *inode, struct file *file)
253 {
254 	struct joydev_client *client;
255 	struct joydev *joydev;
256 	int i = iminor(inode) - JOYDEV_MINOR_BASE;
257 	int error;
258 
259 	if (i >= JOYDEV_MINORS)
260 		return -ENODEV;
261 
262 	error = mutex_lock_interruptible(&joydev_table_mutex);
263 	if (error)
264 		return error;
265 	joydev = joydev_table[i];
266 	if (joydev)
267 		get_device(&joydev->dev);
268 	mutex_unlock(&joydev_table_mutex);
269 
270 	if (!joydev)
271 		return -ENODEV;
272 
273 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
274 	if (!client) {
275 		error = -ENOMEM;
276 		goto err_put_joydev;
277 	}
278 
279 	spin_lock_init(&client->buffer_lock);
280 	client->joydev = joydev;
281 	joydev_attach_client(joydev, client);
282 
283 	error = joydev_open_device(joydev);
284 	if (error)
285 		goto err_free_client;
286 
287 	file->private_data = client;
288 	return 0;
289 
290  err_free_client:
291 	joydev_detach_client(joydev, client);
292 	kfree(client);
293  err_put_joydev:
294 	put_device(&joydev->dev);
295 	return error;
296 }
297 
298 static int joydev_generate_startup_event(struct joydev_client *client,
299 					 struct input_dev *input,
300 					 struct js_event *event)
301 {
302 	struct joydev *joydev = client->joydev;
303 	int have_event;
304 
305 	spin_lock_irq(&client->buffer_lock);
306 
307 	have_event = client->startup < joydev->nabs + joydev->nkey;
308 
309 	if (have_event) {
310 
311 		event->time = jiffies_to_msecs(jiffies);
312 		if (client->startup < joydev->nkey) {
313 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
314 			event->number = client->startup;
315 			event->value = !!test_bit(joydev->keypam[event->number],
316 						  input->key);
317 		} else {
318 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
319 			event->number = client->startup - joydev->nkey;
320 			event->value = joydev->abs[event->number];
321 		}
322 		client->startup++;
323 	}
324 
325 	spin_unlock_irq(&client->buffer_lock);
326 
327 	return have_event;
328 }
329 
330 static int joydev_fetch_next_event(struct joydev_client *client,
331 				   struct js_event *event)
332 {
333 	int have_event;
334 
335 	spin_lock_irq(&client->buffer_lock);
336 
337 	have_event = client->head != client->tail;
338 	if (have_event) {
339 		*event = client->buffer[client->tail++];
340 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
341 	}
342 
343 	spin_unlock_irq(&client->buffer_lock);
344 
345 	return have_event;
346 }
347 
348 /*
349  * Old joystick interface
350  */
351 static ssize_t joydev_0x_read(struct joydev_client *client,
352 			      struct input_dev *input,
353 			      char __user *buf)
354 {
355 	struct joydev *joydev = client->joydev;
356 	struct JS_DATA_TYPE data;
357 	int i;
358 
359 	spin_lock_irq(&input->event_lock);
360 
361 	/*
362 	 * Get device state
363 	 */
364 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
365 		data.buttons |=
366 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
367 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
368 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
369 
370 	/*
371 	 * Reset reader's event queue
372 	 */
373 	spin_lock(&client->buffer_lock);
374 	client->startup = 0;
375 	client->tail = client->head;
376 	spin_unlock(&client->buffer_lock);
377 
378 	spin_unlock_irq(&input->event_lock);
379 
380 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
381 		return -EFAULT;
382 
383 	return sizeof(struct JS_DATA_TYPE);
384 }
385 
386 static inline int joydev_data_pending(struct joydev_client *client)
387 {
388 	struct joydev *joydev = client->joydev;
389 
390 	return client->startup < joydev->nabs + joydev->nkey ||
391 		client->head != client->tail;
392 }
393 
394 static ssize_t joydev_read(struct file *file, char __user *buf,
395 			   size_t count, loff_t *ppos)
396 {
397 	struct joydev_client *client = file->private_data;
398 	struct joydev *joydev = client->joydev;
399 	struct input_dev *input = joydev->handle.dev;
400 	struct js_event event;
401 	int retval;
402 
403 	if (!joydev->exist)
404 		return -ENODEV;
405 
406 	if (count < sizeof(struct js_event))
407 		return -EINVAL;
408 
409 	if (count == sizeof(struct JS_DATA_TYPE))
410 		return joydev_0x_read(client, input, buf);
411 
412 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
413 		return -EAGAIN;
414 
415 	retval = wait_event_interruptible(joydev->wait,
416 			!joydev->exist || joydev_data_pending(client));
417 	if (retval)
418 		return retval;
419 
420 	if (!joydev->exist)
421 		return -ENODEV;
422 
423 	while (retval + sizeof(struct js_event) <= count &&
424 	       joydev_generate_startup_event(client, input, &event)) {
425 
426 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
427 			return -EFAULT;
428 
429 		retval += sizeof(struct js_event);
430 	}
431 
432 	while (retval + sizeof(struct js_event) <= count &&
433 	       joydev_fetch_next_event(client, &event)) {
434 
435 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
436 			return -EFAULT;
437 
438 		retval += sizeof(struct js_event);
439 	}
440 
441 	return retval;
442 }
443 
444 /* No kernel lock - fine */
445 static unsigned int joydev_poll(struct file *file, poll_table *wait)
446 {
447 	struct joydev_client *client = file->private_data;
448 	struct joydev *joydev = client->joydev;
449 
450 	poll_wait(file, &joydev->wait, wait);
451 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
452 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
453 }
454 
455 static int joydev_ioctl_common(struct joydev *joydev,
456 				unsigned int cmd, void __user *argp)
457 {
458 	struct input_dev *dev = joydev->handle.dev;
459 	int i, j;
460 
461 	switch (cmd) {
462 
463 	case JS_SET_CAL:
464 		return copy_from_user(&joydev->glue.JS_CORR, argp,
465 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
466 
467 	case JS_GET_CAL:
468 		return copy_to_user(argp, &joydev->glue.JS_CORR,
469 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
470 
471 	case JS_SET_TIMEOUT:
472 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
473 
474 	case JS_GET_TIMEOUT:
475 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
476 
477 	case JSIOCGVERSION:
478 		return put_user(JS_VERSION, (__u32 __user *) argp);
479 
480 	case JSIOCGAXES:
481 		return put_user(joydev->nabs, (__u8 __user *) argp);
482 
483 	case JSIOCGBUTTONS:
484 		return put_user(joydev->nkey, (__u8 __user *) argp);
485 
486 	case JSIOCSCORR:
487 		if (copy_from_user(joydev->corr, argp,
488 			      sizeof(joydev->corr[0]) * joydev->nabs))
489 		    return -EFAULT;
490 
491 		for (i = 0; i < joydev->nabs; i++) {
492 			j = joydev->abspam[i];
493 			joydev->abs[i] = joydev_correct(dev->abs[j],
494 							&joydev->corr[i]);
495 		}
496 		return 0;
497 
498 	case JSIOCGCORR:
499 		return copy_to_user(argp, joydev->corr,
500 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
501 
502 	case JSIOCSAXMAP:
503 		if (copy_from_user(joydev->abspam, argp,
504 				   sizeof(__u8) * (ABS_MAX + 1)))
505 			return -EFAULT;
506 
507 		for (i = 0; i < joydev->nabs; i++) {
508 			if (joydev->abspam[i] > ABS_MAX)
509 				return -EINVAL;
510 			joydev->absmap[joydev->abspam[i]] = i;
511 		}
512 		return 0;
513 
514 	case JSIOCGAXMAP:
515 		return copy_to_user(argp, joydev->abspam,
516 			sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
517 
518 	case JSIOCSBTNMAP:
519 		if (copy_from_user(joydev->keypam, argp,
520 				   sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
521 			return -EFAULT;
522 
523 		for (i = 0; i < joydev->nkey; i++) {
524 			if (joydev->keypam[i] > KEY_MAX ||
525 			    joydev->keypam[i] < BTN_MISC)
526 				return -EINVAL;
527 			joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
528 		}
529 
530 		return 0;
531 
532 	case JSIOCGBTNMAP:
533 		return copy_to_user(argp, joydev->keypam,
534 			sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
535 
536 	default:
537 		if ((cmd & ~IOCSIZE_MASK) == JSIOCGNAME(0)) {
538 			int len;
539 			const char *name = dev->name;
540 
541 			if (!name)
542 				return 0;
543 			len = strlen(name) + 1;
544 			if (len > _IOC_SIZE(cmd))
545 				len = _IOC_SIZE(cmd);
546 			if (copy_to_user(argp, name, len))
547 				return -EFAULT;
548 			return len;
549 		}
550 	}
551 	return -EINVAL;
552 }
553 
554 #ifdef CONFIG_COMPAT
555 static long joydev_compat_ioctl(struct file *file,
556 				unsigned int cmd, unsigned long arg)
557 {
558 	struct joydev_client *client = file->private_data;
559 	struct joydev *joydev = client->joydev;
560 	void __user *argp = (void __user *)arg;
561 	s32 tmp32;
562 	struct JS_DATA_SAVE_TYPE_32 ds32;
563 	int retval;
564 
565 	retval = mutex_lock_interruptible(&joydev->mutex);
566 	if (retval)
567 		return retval;
568 
569 	if (!joydev->exist) {
570 		retval = -ENODEV;
571 		goto out;
572 	}
573 
574 	switch (cmd) {
575 
576 	case JS_SET_TIMELIMIT:
577 		retval = get_user(tmp32, (s32 __user *) arg);
578 		if (retval == 0)
579 			joydev->glue.JS_TIMELIMIT = tmp32;
580 		break;
581 
582 	case JS_GET_TIMELIMIT:
583 		tmp32 = joydev->glue.JS_TIMELIMIT;
584 		retval = put_user(tmp32, (s32 __user *) arg);
585 		break;
586 
587 	case JS_SET_ALL:
588 		retval = copy_from_user(&ds32, argp,
589 					sizeof(ds32)) ? -EFAULT : 0;
590 		if (retval == 0) {
591 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
592 			joydev->glue.BUSY          = ds32.BUSY;
593 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
594 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
595 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
596 			joydev->glue.JS_CORR       = ds32.JS_CORR;
597 		}
598 		break;
599 
600 	case JS_GET_ALL:
601 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
602 		ds32.BUSY          = joydev->glue.BUSY;
603 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
604 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
605 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
606 		ds32.JS_CORR       = joydev->glue.JS_CORR;
607 
608 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
609 		break;
610 
611 	default:
612 		retval = joydev_ioctl_common(joydev, cmd, argp);
613 		break;
614 	}
615 
616  out:
617 	mutex_unlock(&joydev->mutex);
618 	return retval;
619 }
620 #endif /* CONFIG_COMPAT */
621 
622 static long joydev_ioctl(struct file *file,
623 			 unsigned int cmd, unsigned long arg)
624 {
625 	struct joydev_client *client = file->private_data;
626 	struct joydev *joydev = client->joydev;
627 	void __user *argp = (void __user *)arg;
628 	int retval;
629 
630 	retval = mutex_lock_interruptible(&joydev->mutex);
631 	if (retval)
632 		return retval;
633 
634 	if (!joydev->exist) {
635 		retval = -ENODEV;
636 		goto out;
637 	}
638 
639 	switch (cmd) {
640 
641 	case JS_SET_TIMELIMIT:
642 		retval = get_user(joydev->glue.JS_TIMELIMIT,
643 				  (long __user *) arg);
644 		break;
645 
646 	case JS_GET_TIMELIMIT:
647 		retval = put_user(joydev->glue.JS_TIMELIMIT,
648 				  (long __user *) arg);
649 		break;
650 
651 	case JS_SET_ALL:
652 		retval = copy_from_user(&joydev->glue, argp,
653 					sizeof(joydev->glue)) ? -EFAULT: 0;
654 		break;
655 
656 	case JS_GET_ALL:
657 		retval = copy_to_user(argp, &joydev->glue,
658 				      sizeof(joydev->glue)) ? -EFAULT : 0;
659 		break;
660 
661 	default:
662 		retval = joydev_ioctl_common(joydev, cmd, argp);
663 		break;
664 	}
665  out:
666 	mutex_unlock(&joydev->mutex);
667 	return retval;
668 }
669 
670 static const struct file_operations joydev_fops = {
671 	.owner		= THIS_MODULE,
672 	.read		= joydev_read,
673 	.poll		= joydev_poll,
674 	.open		= joydev_open,
675 	.release	= joydev_release,
676 	.unlocked_ioctl	= joydev_ioctl,
677 #ifdef CONFIG_COMPAT
678 	.compat_ioctl	= joydev_compat_ioctl,
679 #endif
680 	.fasync		= joydev_fasync,
681 };
682 
683 static int joydev_install_chrdev(struct joydev *joydev)
684 {
685 	joydev_table[joydev->minor] = joydev;
686 	return 0;
687 }
688 
689 static void joydev_remove_chrdev(struct joydev *joydev)
690 {
691 	mutex_lock(&joydev_table_mutex);
692 	joydev_table[joydev->minor] = NULL;
693 	mutex_unlock(&joydev_table_mutex);
694 }
695 
696 /*
697  * Mark device non-existant. This disables writes, ioctls and
698  * prevents new users from opening the device. Already posted
699  * blocking reads will stay, however new ones will fail.
700  */
701 static void joydev_mark_dead(struct joydev *joydev)
702 {
703 	mutex_lock(&joydev->mutex);
704 	joydev->exist = 0;
705 	mutex_unlock(&joydev->mutex);
706 }
707 
708 static void joydev_cleanup(struct joydev *joydev)
709 {
710 	struct input_handle *handle = &joydev->handle;
711 
712 	joydev_mark_dead(joydev);
713 	joydev_hangup(joydev);
714 	joydev_remove_chrdev(joydev);
715 
716 	/* joydev is marked dead so noone else accesses joydev->open */
717 	if (joydev->open)
718 		input_close_device(handle);
719 }
720 
721 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
722 			  const struct input_device_id *id)
723 {
724 	struct joydev *joydev;
725 	int i, j, t, minor;
726 	int error;
727 
728 	for (minor = 0; minor < JOYDEV_MINORS; minor++)
729 		if (!joydev_table[minor])
730 			break;
731 
732 	if (minor == JOYDEV_MINORS) {
733 		printk(KERN_ERR "joydev: no more free joydev devices\n");
734 		return -ENFILE;
735 	}
736 
737 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
738 	if (!joydev)
739 		return -ENOMEM;
740 
741 	INIT_LIST_HEAD(&joydev->client_list);
742 	spin_lock_init(&joydev->client_lock);
743 	mutex_init(&joydev->mutex);
744 	init_waitqueue_head(&joydev->wait);
745 
746 	dev_set_name(&joydev->dev, "js%d", minor);
747 	joydev->exist = 1;
748 	joydev->minor = minor;
749 
750 	joydev->exist = 1;
751 	joydev->handle.dev = input_get_device(dev);
752 	joydev->handle.name = dev_name(&joydev->dev);
753 	joydev->handle.handler = handler;
754 	joydev->handle.private = joydev;
755 
756 	for (i = 0; i < ABS_MAX + 1; i++)
757 		if (test_bit(i, dev->absbit)) {
758 			joydev->absmap[i] = joydev->nabs;
759 			joydev->abspam[joydev->nabs] = i;
760 			joydev->nabs++;
761 		}
762 
763 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
764 		if (test_bit(i + BTN_MISC, dev->keybit)) {
765 			joydev->keymap[i] = joydev->nkey;
766 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
767 			joydev->nkey++;
768 		}
769 
770 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
771 		if (test_bit(i + BTN_MISC, dev->keybit)) {
772 			joydev->keymap[i] = joydev->nkey;
773 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
774 			joydev->nkey++;
775 		}
776 
777 	for (i = 0; i < joydev->nabs; i++) {
778 		j = joydev->abspam[i];
779 		if (dev->absmax[j] == dev->absmin[j]) {
780 			joydev->corr[i].type = JS_CORR_NONE;
781 			joydev->abs[i] = dev->abs[j];
782 			continue;
783 		}
784 		joydev->corr[i].type = JS_CORR_BROKEN;
785 		joydev->corr[i].prec = dev->absfuzz[j];
786 		joydev->corr[i].coef[0] =
787 			(dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
788 		joydev->corr[i].coef[1] =
789 			(dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
790 
791 		t = (dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j];
792 		if (t) {
793 			joydev->corr[i].coef[2] = (1 << 29) / t;
794 			joydev->corr[i].coef[3] = (1 << 29) / t;
795 
796 			joydev->abs[i] = joydev_correct(dev->abs[j],
797 							joydev->corr + i);
798 		}
799 	}
800 
801 	joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
802 	joydev->dev.class = &input_class;
803 	joydev->dev.parent = &dev->dev;
804 	joydev->dev.release = joydev_free;
805 	device_initialize(&joydev->dev);
806 
807 	error = input_register_handle(&joydev->handle);
808 	if (error)
809 		goto err_free_joydev;
810 
811 	error = joydev_install_chrdev(joydev);
812 	if (error)
813 		goto err_unregister_handle;
814 
815 	error = device_add(&joydev->dev);
816 	if (error)
817 		goto err_cleanup_joydev;
818 
819 	return 0;
820 
821  err_cleanup_joydev:
822 	joydev_cleanup(joydev);
823  err_unregister_handle:
824 	input_unregister_handle(&joydev->handle);
825  err_free_joydev:
826 	put_device(&joydev->dev);
827 	return error;
828 }
829 
830 static void joydev_disconnect(struct input_handle *handle)
831 {
832 	struct joydev *joydev = handle->private;
833 
834 	device_del(&joydev->dev);
835 	joydev_cleanup(joydev);
836 	input_unregister_handle(handle);
837 	put_device(&joydev->dev);
838 }
839 
840 static const struct input_device_id joydev_blacklist[] = {
841 	{
842 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
843 				INPUT_DEVICE_ID_MATCH_KEYBIT,
844 		.evbit = { BIT_MASK(EV_KEY) },
845 		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
846 	},	/* Avoid itouchpads and touchscreens */
847 	{
848 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
849 				INPUT_DEVICE_ID_MATCH_KEYBIT,
850 		.evbit = { BIT_MASK(EV_KEY) },
851 		.keybit = { [BIT_WORD(BTN_DIGI)] = BIT_MASK(BTN_DIGI) },
852 	},	/* Avoid tablets, digitisers and similar devices */
853 	{ }	/* Terminating entry */
854 };
855 
856 static const struct input_device_id joydev_ids[] = {
857 	{
858 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
859 				INPUT_DEVICE_ID_MATCH_ABSBIT,
860 		.evbit = { BIT_MASK(EV_ABS) },
861 		.absbit = { BIT_MASK(ABS_X) },
862 	},
863 	{
864 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
865 				INPUT_DEVICE_ID_MATCH_ABSBIT,
866 		.evbit = { BIT_MASK(EV_ABS) },
867 		.absbit = { BIT_MASK(ABS_WHEEL) },
868 	},
869 	{
870 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
871 				INPUT_DEVICE_ID_MATCH_ABSBIT,
872 		.evbit = { BIT_MASK(EV_ABS) },
873 		.absbit = { BIT_MASK(ABS_THROTTLE) },
874 	},
875 	{ }	/* Terminating entry */
876 };
877 
878 MODULE_DEVICE_TABLE(input, joydev_ids);
879 
880 static struct input_handler joydev_handler = {
881 	.event		= joydev_event,
882 	.connect	= joydev_connect,
883 	.disconnect	= joydev_disconnect,
884 	.fops		= &joydev_fops,
885 	.minor		= JOYDEV_MINOR_BASE,
886 	.name		= "joydev",
887 	.id_table	= joydev_ids,
888 	.blacklist	= joydev_blacklist,
889 };
890 
891 static int __init joydev_init(void)
892 {
893 	return input_register_handler(&joydev_handler);
894 }
895 
896 static void __exit joydev_exit(void)
897 {
898 	input_unregister_handler(&joydev_handler);
899 }
900 
901 module_init(joydev_init);
902 module_exit(joydev_exit);
903