xref: /openbmc/linux/drivers/input/joydev.c (revision f42b3800)
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 	char name[16];
43 	struct input_handle handle;
44 	wait_queue_head_t wait;
45 	struct list_head client_list;
46 	spinlock_t client_lock; /* protects client_list */
47 	struct mutex mutex;
48 	struct device dev;
49 
50 	struct js_corr corr[ABS_MAX + 1];
51 	struct JS_DATA_SAVE_TYPE glue;
52 	int nabs;
53 	int nkey;
54 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
55 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
56 	__u8 absmap[ABS_MAX + 1];
57 	__u8 abspam[ABS_MAX + 1];
58 	__s16 abs[ABS_MAX + 1];
59 };
60 
61 struct joydev_client {
62 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
63 	int head;
64 	int tail;
65 	int startup;
66 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
67 	struct fasync_struct *fasync;
68 	struct joydev *joydev;
69 	struct list_head node;
70 };
71 
72 static struct joydev *joydev_table[JOYDEV_MINORS];
73 static DEFINE_MUTEX(joydev_table_mutex);
74 
75 static int joydev_correct(int value, struct js_corr *corr)
76 {
77 	switch (corr->type) {
78 
79 	case JS_CORR_NONE:
80 		break;
81 
82 	case JS_CORR_BROKEN:
83 		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
84 			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
85 			((corr->coef[2] * (value - corr->coef[0])) >> 14);
86 		break;
87 
88 	default:
89 		return 0;
90 	}
91 
92 	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
93 }
94 
95 static void joydev_pass_event(struct joydev_client *client,
96 			      struct js_event *event)
97 {
98 	struct joydev *joydev = client->joydev;
99 
100 	/*
101 	 * IRQs already disabled, just acquire the lock
102 	 */
103 	spin_lock(&client->buffer_lock);
104 
105 	client->buffer[client->head] = *event;
106 
107 	if (client->startup == joydev->nabs + joydev->nkey) {
108 		client->head++;
109 		client->head &= JOYDEV_BUFFER_SIZE - 1;
110 		if (client->tail == client->head)
111 			client->startup = 0;
112 	}
113 
114 	spin_unlock(&client->buffer_lock);
115 
116 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
117 }
118 
119 static void joydev_event(struct input_handle *handle,
120 			 unsigned int type, unsigned int code, int value)
121 {
122 	struct joydev *joydev = handle->private;
123 	struct joydev_client *client;
124 	struct js_event event;
125 
126 	switch (type) {
127 
128 	case EV_KEY:
129 		if (code < BTN_MISC || value == 2)
130 			return;
131 		event.type = JS_EVENT_BUTTON;
132 		event.number = joydev->keymap[code - BTN_MISC];
133 		event.value = value;
134 		break;
135 
136 	case EV_ABS:
137 		event.type = JS_EVENT_AXIS;
138 		event.number = joydev->absmap[code];
139 		event.value = joydev_correct(value,
140 					&joydev->corr[event.number]);
141 		if (event.value == joydev->abs[event.number])
142 			return;
143 		joydev->abs[event.number] = event.value;
144 		break;
145 
146 	default:
147 		return;
148 	}
149 
150 	event.time = jiffies_to_msecs(jiffies);
151 
152 	rcu_read_lock();
153 	list_for_each_entry_rcu(client, &joydev->client_list, node)
154 		joydev_pass_event(client, &event);
155 	rcu_read_unlock();
156 
157 	wake_up_interruptible(&joydev->wait);
158 }
159 
160 static int joydev_fasync(int fd, struct file *file, int on)
161 {
162 	int retval;
163 	struct joydev_client *client = file->private_data;
164 
165 	retval = fasync_helper(fd, file, on, &client->fasync);
166 
167 	return retval < 0 ? retval : 0;
168 }
169 
170 static void joydev_free(struct device *dev)
171 {
172 	struct joydev *joydev = container_of(dev, struct joydev, dev);
173 
174 	input_put_device(joydev->handle.dev);
175 	kfree(joydev);
176 }
177 
178 static void joydev_attach_client(struct joydev *joydev,
179 				 struct joydev_client *client)
180 {
181 	spin_lock(&joydev->client_lock);
182 	list_add_tail_rcu(&client->node, &joydev->client_list);
183 	spin_unlock(&joydev->client_lock);
184 	synchronize_rcu();
185 }
186 
187 static void joydev_detach_client(struct joydev *joydev,
188 				 struct joydev_client *client)
189 {
190 	spin_lock(&joydev->client_lock);
191 	list_del_rcu(&client->node);
192 	spin_unlock(&joydev->client_lock);
193 	synchronize_rcu();
194 }
195 
196 static int joydev_open_device(struct joydev *joydev)
197 {
198 	int retval;
199 
200 	retval = mutex_lock_interruptible(&joydev->mutex);
201 	if (retval)
202 		return retval;
203 
204 	if (!joydev->exist)
205 		retval = -ENODEV;
206 	else if (!joydev->open++) {
207 		retval = input_open_device(&joydev->handle);
208 		if (retval)
209 			joydev->open--;
210 	}
211 
212 	mutex_unlock(&joydev->mutex);
213 	return retval;
214 }
215 
216 static void joydev_close_device(struct joydev *joydev)
217 {
218 	mutex_lock(&joydev->mutex);
219 
220 	if (joydev->exist && !--joydev->open)
221 		input_close_device(&joydev->handle);
222 
223 	mutex_unlock(&joydev->mutex);
224 }
225 
226 /*
227  * Wake up users waiting for IO so they can disconnect from
228  * dead device.
229  */
230 static void joydev_hangup(struct joydev *joydev)
231 {
232 	struct joydev_client *client;
233 
234 	spin_lock(&joydev->client_lock);
235 	list_for_each_entry(client, &joydev->client_list, node)
236 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
237 	spin_unlock(&joydev->client_lock);
238 
239 	wake_up_interruptible(&joydev->wait);
240 }
241 
242 static int joydev_release(struct inode *inode, struct file *file)
243 {
244 	struct joydev_client *client = file->private_data;
245 	struct joydev *joydev = client->joydev;
246 
247 	joydev_fasync(-1, file, 0);
248 	joydev_detach_client(joydev, client);
249 	kfree(client);
250 
251 	joydev_close_device(joydev);
252 	put_device(&joydev->dev);
253 
254 	return 0;
255 }
256 
257 static int joydev_open(struct inode *inode, struct file *file)
258 {
259 	struct joydev_client *client;
260 	struct joydev *joydev;
261 	int i = iminor(inode) - JOYDEV_MINOR_BASE;
262 	int error;
263 
264 	if (i >= JOYDEV_MINORS)
265 		return -ENODEV;
266 
267 	error = mutex_lock_interruptible(&joydev_table_mutex);
268 	if (error)
269 		return error;
270 	joydev = joydev_table[i];
271 	if (joydev)
272 		get_device(&joydev->dev);
273 	mutex_unlock(&joydev_table_mutex);
274 
275 	if (!joydev)
276 		return -ENODEV;
277 
278 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
279 	if (!client) {
280 		error = -ENOMEM;
281 		goto err_put_joydev;
282 	}
283 
284 	spin_lock_init(&client->buffer_lock);
285 	client->joydev = joydev;
286 	joydev_attach_client(joydev, client);
287 
288 	error = joydev_open_device(joydev);
289 	if (error)
290 		goto err_free_client;
291 
292 	file->private_data = client;
293 	return 0;
294 
295  err_free_client:
296 	joydev_detach_client(joydev, client);
297 	kfree(client);
298  err_put_joydev:
299 	put_device(&joydev->dev);
300 	return error;
301 }
302 
303 static int joydev_generate_startup_event(struct joydev_client *client,
304 					 struct input_dev *input,
305 					 struct js_event *event)
306 {
307 	struct joydev *joydev = client->joydev;
308 	int have_event;
309 
310 	spin_lock_irq(&client->buffer_lock);
311 
312 	have_event = client->startup < joydev->nabs + joydev->nkey;
313 
314 	if (have_event) {
315 
316 		event->time = jiffies_to_msecs(jiffies);
317 		if (client->startup < joydev->nkey) {
318 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
319 			event->number = client->startup;
320 			event->value = !!test_bit(joydev->keypam[event->number],
321 						  input->key);
322 		} else {
323 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
324 			event->number = client->startup - joydev->nkey;
325 			event->value = joydev->abs[event->number];
326 		}
327 		client->startup++;
328 	}
329 
330 	spin_unlock_irq(&client->buffer_lock);
331 
332 	return have_event;
333 }
334 
335 static int joydev_fetch_next_event(struct joydev_client *client,
336 				   struct js_event *event)
337 {
338 	int have_event;
339 
340 	spin_lock_irq(&client->buffer_lock);
341 
342 	have_event = client->head != client->tail;
343 	if (have_event) {
344 		*event = client->buffer[client->tail++];
345 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
346 	}
347 
348 	spin_unlock_irq(&client->buffer_lock);
349 
350 	return have_event;
351 }
352 
353 /*
354  * Old joystick interface
355  */
356 static ssize_t joydev_0x_read(struct joydev_client *client,
357 			      struct input_dev *input,
358 			      char __user *buf)
359 {
360 	struct joydev *joydev = client->joydev;
361 	struct JS_DATA_TYPE data;
362 	int i;
363 
364 	spin_lock_irq(&input->event_lock);
365 
366 	/*
367 	 * Get device state
368 	 */
369 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
370 		data.buttons |=
371 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
372 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
373 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
374 
375 	/*
376 	 * Reset reader's event queue
377 	 */
378 	spin_lock(&client->buffer_lock);
379 	client->startup = 0;
380 	client->tail = client->head;
381 	spin_unlock(&client->buffer_lock);
382 
383 	spin_unlock_irq(&input->event_lock);
384 
385 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
386 		return -EFAULT;
387 
388 	return sizeof(struct JS_DATA_TYPE);
389 }
390 
391 static inline int joydev_data_pending(struct joydev_client *client)
392 {
393 	struct joydev *joydev = client->joydev;
394 
395 	return client->startup < joydev->nabs + joydev->nkey ||
396 		client->head != client->tail;
397 }
398 
399 static ssize_t joydev_read(struct file *file, char __user *buf,
400 			   size_t count, loff_t *ppos)
401 {
402 	struct joydev_client *client = file->private_data;
403 	struct joydev *joydev = client->joydev;
404 	struct input_dev *input = joydev->handle.dev;
405 	struct js_event event;
406 	int retval;
407 
408 	if (!joydev->exist)
409 		return -ENODEV;
410 
411 	if (count < sizeof(struct js_event))
412 		return -EINVAL;
413 
414 	if (count == sizeof(struct JS_DATA_TYPE))
415 		return joydev_0x_read(client, input, buf);
416 
417 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
418 		return -EAGAIN;
419 
420 	retval = wait_event_interruptible(joydev->wait,
421 			!joydev->exist || joydev_data_pending(client));
422 	if (retval)
423 		return retval;
424 
425 	if (!joydev->exist)
426 		return -ENODEV;
427 
428 	while (retval + sizeof(struct js_event) <= count &&
429 	       joydev_generate_startup_event(client, input, &event)) {
430 
431 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
432 			return -EFAULT;
433 
434 		retval += sizeof(struct js_event);
435 	}
436 
437 	while (retval + sizeof(struct js_event) <= count &&
438 	       joydev_fetch_next_event(client, &event)) {
439 
440 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
441 			return -EFAULT;
442 
443 		retval += sizeof(struct js_event);
444 	}
445 
446 	return retval;
447 }
448 
449 /* No kernel lock - fine */
450 static unsigned int joydev_poll(struct file *file, poll_table *wait)
451 {
452 	struct joydev_client *client = file->private_data;
453 	struct joydev *joydev = client->joydev;
454 
455 	poll_wait(file, &joydev->wait, wait);
456 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
457 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
458 }
459 
460 static int joydev_ioctl_common(struct joydev *joydev,
461 				unsigned int cmd, void __user *argp)
462 {
463 	struct input_dev *dev = joydev->handle.dev;
464 	int i, j;
465 
466 	switch (cmd) {
467 
468 	case JS_SET_CAL:
469 		return copy_from_user(&joydev->glue.JS_CORR, argp,
470 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
471 
472 	case JS_GET_CAL:
473 		return copy_to_user(argp, &joydev->glue.JS_CORR,
474 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
475 
476 	case JS_SET_TIMEOUT:
477 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
478 
479 	case JS_GET_TIMEOUT:
480 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
481 
482 	case JSIOCGVERSION:
483 		return put_user(JS_VERSION, (__u32 __user *) argp);
484 
485 	case JSIOCGAXES:
486 		return put_user(joydev->nabs, (__u8 __user *) argp);
487 
488 	case JSIOCGBUTTONS:
489 		return put_user(joydev->nkey, (__u8 __user *) argp);
490 
491 	case JSIOCSCORR:
492 		if (copy_from_user(joydev->corr, argp,
493 			      sizeof(joydev->corr[0]) * joydev->nabs))
494 		    return -EFAULT;
495 
496 		for (i = 0; i < joydev->nabs; i++) {
497 			j = joydev->abspam[i];
498 			joydev->abs[i] = joydev_correct(dev->abs[j],
499 							&joydev->corr[i]);
500 		}
501 		return 0;
502 
503 	case JSIOCGCORR:
504 		return copy_to_user(argp, joydev->corr,
505 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
506 
507 	case JSIOCSAXMAP:
508 		if (copy_from_user(joydev->abspam, argp,
509 				   sizeof(__u8) * (ABS_MAX + 1)))
510 			return -EFAULT;
511 
512 		for (i = 0; i < joydev->nabs; i++) {
513 			if (joydev->abspam[i] > ABS_MAX)
514 				return -EINVAL;
515 			joydev->absmap[joydev->abspam[i]] = i;
516 		}
517 		return 0;
518 
519 	case JSIOCGAXMAP:
520 		return copy_to_user(argp, joydev->abspam,
521 			sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
522 
523 	case JSIOCSBTNMAP:
524 		if (copy_from_user(joydev->keypam, argp,
525 				   sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
526 			return -EFAULT;
527 
528 		for (i = 0; i < joydev->nkey; i++) {
529 			if (joydev->keypam[i] > KEY_MAX ||
530 			    joydev->keypam[i] < BTN_MISC)
531 				return -EINVAL;
532 			joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
533 		}
534 
535 		return 0;
536 
537 	case JSIOCGBTNMAP:
538 		return copy_to_user(argp, joydev->keypam,
539 			sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
540 
541 	default:
542 		if ((cmd & ~IOCSIZE_MASK) == JSIOCGNAME(0)) {
543 			int len;
544 			if (!dev->name)
545 				return 0;
546 			len = strlen(dev->name) + 1;
547 			if (len > _IOC_SIZE(cmd))
548 				len = _IOC_SIZE(cmd);
549 			if (copy_to_user(argp, dev->name, len))
550 				return -EFAULT;
551 			return len;
552 		}
553 	}
554 	return -EINVAL;
555 }
556 
557 #ifdef CONFIG_COMPAT
558 static long joydev_compat_ioctl(struct file *file,
559 				unsigned int cmd, unsigned long arg)
560 {
561 	struct joydev_client *client = file->private_data;
562 	struct joydev *joydev = client->joydev;
563 	void __user *argp = (void __user *)arg;
564 	s32 tmp32;
565 	struct JS_DATA_SAVE_TYPE_32 ds32;
566 	int retval;
567 
568 	retval = mutex_lock_interruptible(&joydev->mutex);
569 	if (retval)
570 		return retval;
571 
572 	if (!joydev->exist) {
573 		retval = -ENODEV;
574 		goto out;
575 	}
576 
577 	switch (cmd) {
578 
579 	case JS_SET_TIMELIMIT:
580 		retval = get_user(tmp32, (s32 __user *) arg);
581 		if (retval == 0)
582 			joydev->glue.JS_TIMELIMIT = tmp32;
583 		break;
584 
585 	case JS_GET_TIMELIMIT:
586 		tmp32 = joydev->glue.JS_TIMELIMIT;
587 		retval = put_user(tmp32, (s32 __user *) arg);
588 		break;
589 
590 	case JS_SET_ALL:
591 		retval = copy_from_user(&ds32, argp,
592 					sizeof(ds32)) ? -EFAULT : 0;
593 		if (retval == 0) {
594 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
595 			joydev->glue.BUSY          = ds32.BUSY;
596 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
597 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
598 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
599 			joydev->glue.JS_CORR       = ds32.JS_CORR;
600 		}
601 		break;
602 
603 	case JS_GET_ALL:
604 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
605 		ds32.BUSY          = joydev->glue.BUSY;
606 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
607 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
608 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
609 		ds32.JS_CORR       = joydev->glue.JS_CORR;
610 
611 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
612 		break;
613 
614 	default:
615 		retval = joydev_ioctl_common(joydev, cmd, argp);
616 		break;
617 	}
618 
619  out:
620 	mutex_unlock(&joydev->mutex);
621 	return retval;
622 }
623 #endif /* CONFIG_COMPAT */
624 
625 static long joydev_ioctl(struct file *file,
626 			 unsigned int cmd, unsigned long arg)
627 {
628 	struct joydev_client *client = file->private_data;
629 	struct joydev *joydev = client->joydev;
630 	void __user *argp = (void __user *)arg;
631 	int retval;
632 
633 	retval = mutex_lock_interruptible(&joydev->mutex);
634 	if (retval)
635 		return retval;
636 
637 	if (!joydev->exist) {
638 		retval = -ENODEV;
639 		goto out;
640 	}
641 
642 	switch (cmd) {
643 
644 	case JS_SET_TIMELIMIT:
645 		retval = get_user(joydev->glue.JS_TIMELIMIT,
646 				  (long __user *) arg);
647 		break;
648 
649 	case JS_GET_TIMELIMIT:
650 		retval = put_user(joydev->glue.JS_TIMELIMIT,
651 				  (long __user *) arg);
652 		break;
653 
654 	case JS_SET_ALL:
655 		retval = copy_from_user(&joydev->glue, argp,
656 					sizeof(joydev->glue)) ? -EFAULT: 0;
657 		break;
658 
659 	case JS_GET_ALL:
660 		retval = copy_to_user(argp, &joydev->glue,
661 				      sizeof(joydev->glue)) ? -EFAULT : 0;
662 		break;
663 
664 	default:
665 		retval = joydev_ioctl_common(joydev, cmd, argp);
666 		break;
667 	}
668  out:
669 	mutex_unlock(&joydev->mutex);
670 	return retval;
671 }
672 
673 static const struct file_operations joydev_fops = {
674 	.owner		= THIS_MODULE,
675 	.read		= joydev_read,
676 	.poll		= joydev_poll,
677 	.open		= joydev_open,
678 	.release	= joydev_release,
679 	.unlocked_ioctl	= joydev_ioctl,
680 #ifdef CONFIG_COMPAT
681 	.compat_ioctl	= joydev_compat_ioctl,
682 #endif
683 	.fasync		= joydev_fasync,
684 };
685 
686 static int joydev_install_chrdev(struct joydev *joydev)
687 {
688 	joydev_table[joydev->minor] = joydev;
689 	return 0;
690 }
691 
692 static void joydev_remove_chrdev(struct joydev *joydev)
693 {
694 	mutex_lock(&joydev_table_mutex);
695 	joydev_table[joydev->minor] = NULL;
696 	mutex_unlock(&joydev_table_mutex);
697 }
698 
699 /*
700  * Mark device non-existant. This disables writes, ioctls and
701  * prevents new users from opening the device. Already posted
702  * blocking reads will stay, however new ones will fail.
703  */
704 static void joydev_mark_dead(struct joydev *joydev)
705 {
706 	mutex_lock(&joydev->mutex);
707 	joydev->exist = 0;
708 	mutex_unlock(&joydev->mutex);
709 }
710 
711 static void joydev_cleanup(struct joydev *joydev)
712 {
713 	struct input_handle *handle = &joydev->handle;
714 
715 	joydev_mark_dead(joydev);
716 	joydev_hangup(joydev);
717 	joydev_remove_chrdev(joydev);
718 
719 	/* joydev is marked dead so noone else accesses joydev->open */
720 	if (joydev->open)
721 		input_close_device(handle);
722 }
723 
724 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
725 			  const struct input_device_id *id)
726 {
727 	struct joydev *joydev;
728 	int i, j, t, minor;
729 	int error;
730 
731 	for (minor = 0; minor < JOYDEV_MINORS; minor++)
732 		if (!joydev_table[minor])
733 			break;
734 
735 	if (minor == JOYDEV_MINORS) {
736 		printk(KERN_ERR "joydev: no more free joydev devices\n");
737 		return -ENFILE;
738 	}
739 
740 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
741 	if (!joydev)
742 		return -ENOMEM;
743 
744 	INIT_LIST_HEAD(&joydev->client_list);
745 	spin_lock_init(&joydev->client_lock);
746 	mutex_init(&joydev->mutex);
747 	init_waitqueue_head(&joydev->wait);
748 
749 	snprintf(joydev->name, sizeof(joydev->name), "js%d", minor);
750 	joydev->exist = 1;
751 	joydev->minor = minor;
752 
753 	joydev->exist = 1;
754 	joydev->handle.dev = input_get_device(dev);
755 	joydev->handle.name = joydev->name;
756 	joydev->handle.handler = handler;
757 	joydev->handle.private = joydev;
758 
759 	for (i = 0; i < ABS_MAX + 1; i++)
760 		if (test_bit(i, dev->absbit)) {
761 			joydev->absmap[i] = joydev->nabs;
762 			joydev->abspam[joydev->nabs] = i;
763 			joydev->nabs++;
764 		}
765 
766 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
767 		if (test_bit(i + BTN_MISC, dev->keybit)) {
768 			joydev->keymap[i] = joydev->nkey;
769 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
770 			joydev->nkey++;
771 		}
772 
773 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
774 		if (test_bit(i + BTN_MISC, dev->keybit)) {
775 			joydev->keymap[i] = joydev->nkey;
776 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
777 			joydev->nkey++;
778 		}
779 
780 	for (i = 0; i < joydev->nabs; i++) {
781 		j = joydev->abspam[i];
782 		if (dev->absmax[j] == dev->absmin[j]) {
783 			joydev->corr[i].type = JS_CORR_NONE;
784 			joydev->abs[i] = dev->abs[j];
785 			continue;
786 		}
787 		joydev->corr[i].type = JS_CORR_BROKEN;
788 		joydev->corr[i].prec = dev->absfuzz[j];
789 		joydev->corr[i].coef[0] =
790 			(dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
791 		joydev->corr[i].coef[1] =
792 			(dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
793 
794 		t = (dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j];
795 		if (t) {
796 			joydev->corr[i].coef[2] = (1 << 29) / t;
797 			joydev->corr[i].coef[3] = (1 << 29) / t;
798 
799 			joydev->abs[i] = joydev_correct(dev->abs[j],
800 							joydev->corr + i);
801 		}
802 	}
803 
804 	strlcpy(joydev->dev.bus_id, joydev->name, sizeof(joydev->dev.bus_id));
805 	joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
806 	joydev->dev.class = &input_class;
807 	joydev->dev.parent = &dev->dev;
808 	joydev->dev.release = joydev_free;
809 	device_initialize(&joydev->dev);
810 
811 	error = input_register_handle(&joydev->handle);
812 	if (error)
813 		goto err_free_joydev;
814 
815 	error = joydev_install_chrdev(joydev);
816 	if (error)
817 		goto err_unregister_handle;
818 
819 	error = device_add(&joydev->dev);
820 	if (error)
821 		goto err_cleanup_joydev;
822 
823 	return 0;
824 
825  err_cleanup_joydev:
826 	joydev_cleanup(joydev);
827  err_unregister_handle:
828 	input_unregister_handle(&joydev->handle);
829  err_free_joydev:
830 	put_device(&joydev->dev);
831 	return error;
832 }
833 
834 static void joydev_disconnect(struct input_handle *handle)
835 {
836 	struct joydev *joydev = handle->private;
837 
838 	device_del(&joydev->dev);
839 	joydev_cleanup(joydev);
840 	input_unregister_handle(handle);
841 	put_device(&joydev->dev);
842 }
843 
844 static const struct input_device_id joydev_blacklist[] = {
845 	{
846 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
847 				INPUT_DEVICE_ID_MATCH_KEYBIT,
848 		.evbit = { BIT_MASK(EV_KEY) },
849 		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
850 	},	/* Avoid itouchpads, touchscreens and tablets */
851 	{ }	/* Terminating entry */
852 };
853 
854 static const struct input_device_id joydev_ids[] = {
855 	{
856 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
857 				INPUT_DEVICE_ID_MATCH_ABSBIT,
858 		.evbit = { BIT_MASK(EV_ABS) },
859 		.absbit = { BIT_MASK(ABS_X) },
860 	},
861 	{
862 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
863 				INPUT_DEVICE_ID_MATCH_ABSBIT,
864 		.evbit = { BIT_MASK(EV_ABS) },
865 		.absbit = { BIT_MASK(ABS_WHEEL) },
866 	},
867 	{
868 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
869 				INPUT_DEVICE_ID_MATCH_ABSBIT,
870 		.evbit = { BIT_MASK(EV_ABS) },
871 		.absbit = { BIT_MASK(ABS_THROTTLE) },
872 	},
873 	{ }	/* Terminating entry */
874 };
875 
876 MODULE_DEVICE_TABLE(input, joydev_ids);
877 
878 static struct input_handler joydev_handler = {
879 	.event		= joydev_event,
880 	.connect	= joydev_connect,
881 	.disconnect	= joydev_disconnect,
882 	.fops		= &joydev_fops,
883 	.minor		= JOYDEV_MINOR_BASE,
884 	.name		= "joydev",
885 	.id_table	= joydev_ids,
886 	.blacklist	= joydev_blacklist,
887 };
888 
889 static int __init joydev_init(void)
890 {
891 	return input_register_handler(&joydev_handler);
892 }
893 
894 static void __exit joydev_exit(void)
895 {
896 	input_unregister_handler(&joydev_handler);
897 }
898 
899 module_init(joydev_init);
900 module_exit(joydev_exit);
901