xref: /linux/drivers/input/joydev.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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/sched.h>
22 #include <linux/slab.h>
23 #include <linux/mm.h>
24 #include <linux/miscdevice.h>
25 #include <linux/module.h>
26 #include <linux/poll.h>
27 #include <linux/init.h>
28 #include <linux/device.h>
29 
30 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
31 MODULE_DESCRIPTION("Joystick device interfaces");
32 MODULE_SUPPORTED_DEVICE("input/js");
33 MODULE_LICENSE("GPL");
34 
35 #define JOYDEV_MINOR_BASE	0
36 #define JOYDEV_MINORS		16
37 #define JOYDEV_BUFFER_SIZE	64
38 
39 struct joydev {
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 	bool exist;
49 
50 	struct js_corr corr[ABS_CNT];
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_CNT];
57 	__u8 abspam[ABS_CNT];
58 	__s16 abs[ABS_CNT];
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 	struct joydev_client *client = file->private_data;
163 
164 	return fasync_helper(fd, file, on, &client->fasync);
165 }
166 
167 static void joydev_free(struct device *dev)
168 {
169 	struct joydev *joydev = container_of(dev, struct joydev, dev);
170 
171 	input_put_device(joydev->handle.dev);
172 	kfree(joydev);
173 }
174 
175 static void joydev_attach_client(struct joydev *joydev,
176 				 struct joydev_client *client)
177 {
178 	spin_lock(&joydev->client_lock);
179 	list_add_tail_rcu(&client->node, &joydev->client_list);
180 	spin_unlock(&joydev->client_lock);
181 	synchronize_rcu();
182 }
183 
184 static void joydev_detach_client(struct joydev *joydev,
185 				 struct joydev_client *client)
186 {
187 	spin_lock(&joydev->client_lock);
188 	list_del_rcu(&client->node);
189 	spin_unlock(&joydev->client_lock);
190 	synchronize_rcu();
191 }
192 
193 static int joydev_open_device(struct joydev *joydev)
194 {
195 	int retval;
196 
197 	retval = mutex_lock_interruptible(&joydev->mutex);
198 	if (retval)
199 		return retval;
200 
201 	if (!joydev->exist)
202 		retval = -ENODEV;
203 	else if (!joydev->open++) {
204 		retval = input_open_device(&joydev->handle);
205 		if (retval)
206 			joydev->open--;
207 	}
208 
209 	mutex_unlock(&joydev->mutex);
210 	return retval;
211 }
212 
213 static void joydev_close_device(struct joydev *joydev)
214 {
215 	mutex_lock(&joydev->mutex);
216 
217 	if (joydev->exist && !--joydev->open)
218 		input_close_device(&joydev->handle);
219 
220 	mutex_unlock(&joydev->mutex);
221 }
222 
223 /*
224  * Wake up users waiting for IO so they can disconnect from
225  * dead device.
226  */
227 static void joydev_hangup(struct joydev *joydev)
228 {
229 	struct joydev_client *client;
230 
231 	spin_lock(&joydev->client_lock);
232 	list_for_each_entry(client, &joydev->client_list, node)
233 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
234 	spin_unlock(&joydev->client_lock);
235 
236 	wake_up_interruptible(&joydev->wait);
237 }
238 
239 static int joydev_release(struct inode *inode, struct file *file)
240 {
241 	struct joydev_client *client = file->private_data;
242 	struct joydev *joydev = client->joydev;
243 
244 	joydev_detach_client(joydev, client);
245 	kfree(client);
246 
247 	joydev_close_device(joydev);
248 	put_device(&joydev->dev);
249 
250 	return 0;
251 }
252 
253 static int joydev_open(struct inode *inode, struct file *file)
254 {
255 	struct joydev_client *client;
256 	struct joydev *joydev;
257 	int i = iminor(inode) - JOYDEV_MINOR_BASE;
258 	int error;
259 
260 	if (i >= JOYDEV_MINORS)
261 		return -ENODEV;
262 
263 	error = mutex_lock_interruptible(&joydev_table_mutex);
264 	if (error)
265 		return error;
266 	joydev = joydev_table[i];
267 	if (joydev)
268 		get_device(&joydev->dev);
269 	mutex_unlock(&joydev_table_mutex);
270 
271 	if (!joydev)
272 		return -ENODEV;
273 
274 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
275 	if (!client) {
276 		error = -ENOMEM;
277 		goto err_put_joydev;
278 	}
279 
280 	spin_lock_init(&client->buffer_lock);
281 	client->joydev = joydev;
282 	joydev_attach_client(joydev, client);
283 
284 	error = joydev_open_device(joydev);
285 	if (error)
286 		goto err_free_client;
287 
288 	file->private_data = client;
289 	nonseekable_open(inode, file);
290 
291 	return 0;
292 
293  err_free_client:
294 	joydev_detach_client(joydev, client);
295 	kfree(client);
296  err_put_joydev:
297 	put_device(&joydev->dev);
298 	return error;
299 }
300 
301 static int joydev_generate_startup_event(struct joydev_client *client,
302 					 struct input_dev *input,
303 					 struct js_event *event)
304 {
305 	struct joydev *joydev = client->joydev;
306 	int have_event;
307 
308 	spin_lock_irq(&client->buffer_lock);
309 
310 	have_event = client->startup < joydev->nabs + joydev->nkey;
311 
312 	if (have_event) {
313 
314 		event->time = jiffies_to_msecs(jiffies);
315 		if (client->startup < joydev->nkey) {
316 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
317 			event->number = client->startup;
318 			event->value = !!test_bit(joydev->keypam[event->number],
319 						  input->key);
320 		} else {
321 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
322 			event->number = client->startup - joydev->nkey;
323 			event->value = joydev->abs[event->number];
324 		}
325 		client->startup++;
326 	}
327 
328 	spin_unlock_irq(&client->buffer_lock);
329 
330 	return have_event;
331 }
332 
333 static int joydev_fetch_next_event(struct joydev_client *client,
334 				   struct js_event *event)
335 {
336 	int have_event;
337 
338 	spin_lock_irq(&client->buffer_lock);
339 
340 	have_event = client->head != client->tail;
341 	if (have_event) {
342 		*event = client->buffer[client->tail++];
343 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
344 	}
345 
346 	spin_unlock_irq(&client->buffer_lock);
347 
348 	return have_event;
349 }
350 
351 /*
352  * Old joystick interface
353  */
354 static ssize_t joydev_0x_read(struct joydev_client *client,
355 			      struct input_dev *input,
356 			      char __user *buf)
357 {
358 	struct joydev *joydev = client->joydev;
359 	struct JS_DATA_TYPE data;
360 	int i;
361 
362 	spin_lock_irq(&input->event_lock);
363 
364 	/*
365 	 * Get device state
366 	 */
367 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
368 		data.buttons |=
369 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
370 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
371 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
372 
373 	/*
374 	 * Reset reader's event queue
375 	 */
376 	spin_lock(&client->buffer_lock);
377 	client->startup = 0;
378 	client->tail = client->head;
379 	spin_unlock(&client->buffer_lock);
380 
381 	spin_unlock_irq(&input->event_lock);
382 
383 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
384 		return -EFAULT;
385 
386 	return sizeof(struct JS_DATA_TYPE);
387 }
388 
389 static inline int joydev_data_pending(struct joydev_client *client)
390 {
391 	struct joydev *joydev = client->joydev;
392 
393 	return client->startup < joydev->nabs + joydev->nkey ||
394 		client->head != client->tail;
395 }
396 
397 static ssize_t joydev_read(struct file *file, char __user *buf,
398 			   size_t count, loff_t *ppos)
399 {
400 	struct joydev_client *client = file->private_data;
401 	struct joydev *joydev = client->joydev;
402 	struct input_dev *input = joydev->handle.dev;
403 	struct js_event event;
404 	int retval;
405 
406 	if (!joydev->exist)
407 		return -ENODEV;
408 
409 	if (count < sizeof(struct js_event))
410 		return -EINVAL;
411 
412 	if (count == sizeof(struct JS_DATA_TYPE))
413 		return joydev_0x_read(client, input, buf);
414 
415 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
416 		return -EAGAIN;
417 
418 	retval = wait_event_interruptible(joydev->wait,
419 			!joydev->exist || joydev_data_pending(client));
420 	if (retval)
421 		return retval;
422 
423 	if (!joydev->exist)
424 		return -ENODEV;
425 
426 	while (retval + sizeof(struct js_event) <= count &&
427 	       joydev_generate_startup_event(client, input, &event)) {
428 
429 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
430 			return -EFAULT;
431 
432 		retval += sizeof(struct js_event);
433 	}
434 
435 	while (retval + sizeof(struct js_event) <= count &&
436 	       joydev_fetch_next_event(client, &event)) {
437 
438 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
439 			return -EFAULT;
440 
441 		retval += sizeof(struct js_event);
442 	}
443 
444 	return retval;
445 }
446 
447 /* No kernel lock - fine */
448 static unsigned int joydev_poll(struct file *file, poll_table *wait)
449 {
450 	struct joydev_client *client = file->private_data;
451 	struct joydev *joydev = client->joydev;
452 
453 	poll_wait(file, &joydev->wait, wait);
454 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
455 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
456 }
457 
458 static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
459 				     void __user *argp, size_t len)
460 {
461 	__u8 *abspam;
462 	int i;
463 	int retval = 0;
464 
465 	len = min(len, sizeof(joydev->abspam));
466 
467 	/* Validate the map. */
468 	abspam = kmalloc(len, GFP_KERNEL);
469 	if (!abspam)
470 		return -ENOMEM;
471 
472 	if (copy_from_user(abspam, argp, len)) {
473 		retval = -EFAULT;
474 		goto out;
475 	}
476 
477 	for (i = 0; i < joydev->nabs; i++) {
478 		if (abspam[i] > ABS_MAX) {
479 			retval = -EINVAL;
480 			goto out;
481 		}
482 	}
483 
484 	memcpy(joydev->abspam, abspam, len);
485 
486  out:
487 	kfree(abspam);
488 	return retval;
489 }
490 
491 static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
492 				      void __user *argp, size_t len)
493 {
494 	__u16 *keypam;
495 	int i;
496 	int retval = 0;
497 
498 	len = min(len, sizeof(joydev->keypam));
499 
500 	/* Validate the map. */
501 	keypam = kmalloc(len, GFP_KERNEL);
502 	if (!keypam)
503 		return -ENOMEM;
504 
505 	if (copy_from_user(keypam, argp, len)) {
506 		retval = -EFAULT;
507 		goto out;
508 	}
509 
510 	for (i = 0; i < joydev->nkey; i++) {
511 		if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
512 			retval = -EINVAL;
513 			goto out;
514 		}
515 	}
516 
517 	memcpy(joydev->keypam, keypam, len);
518 
519 	for (i = 0; i < joydev->nkey; i++)
520 		joydev->keymap[keypam[i] - BTN_MISC] = i;
521 
522  out:
523 	kfree(keypam);
524 	return retval;
525 }
526 
527 
528 static int joydev_ioctl_common(struct joydev *joydev,
529 				unsigned int cmd, void __user *argp)
530 {
531 	struct input_dev *dev = joydev->handle.dev;
532 	size_t len;
533 	int i;
534 	const char *name;
535 
536 	/* Process fixed-sized commands. */
537 	switch (cmd) {
538 
539 	case JS_SET_CAL:
540 		return copy_from_user(&joydev->glue.JS_CORR, argp,
541 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
542 
543 	case JS_GET_CAL:
544 		return copy_to_user(argp, &joydev->glue.JS_CORR,
545 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
546 
547 	case JS_SET_TIMEOUT:
548 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
549 
550 	case JS_GET_TIMEOUT:
551 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
552 
553 	case JSIOCGVERSION:
554 		return put_user(JS_VERSION, (__u32 __user *) argp);
555 
556 	case JSIOCGAXES:
557 		return put_user(joydev->nabs, (__u8 __user *) argp);
558 
559 	case JSIOCGBUTTONS:
560 		return put_user(joydev->nkey, (__u8 __user *) argp);
561 
562 	case JSIOCSCORR:
563 		if (copy_from_user(joydev->corr, argp,
564 			      sizeof(joydev->corr[0]) * joydev->nabs))
565 			return -EFAULT;
566 
567 		for (i = 0; i < joydev->nabs; i++) {
568 			int val = input_abs_get_val(dev, joydev->abspam[i]);
569 			joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
570 		}
571 		return 0;
572 
573 	case JSIOCGCORR:
574 		return copy_to_user(argp, joydev->corr,
575 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
576 
577 	}
578 
579 	/*
580 	 * Process variable-sized commands (the axis and button map commands
581 	 * are considered variable-sized to decouple them from the values of
582 	 * ABS_MAX and KEY_MAX).
583 	 */
584 	switch (cmd & ~IOCSIZE_MASK) {
585 
586 	case (JSIOCSAXMAP & ~IOCSIZE_MASK):
587 		return joydev_handle_JSIOCSAXMAP(joydev, argp, _IOC_SIZE(cmd));
588 
589 	case (JSIOCGAXMAP & ~IOCSIZE_MASK):
590 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
591 		return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len;
592 
593 	case (JSIOCSBTNMAP & ~IOCSIZE_MASK):
594 		return joydev_handle_JSIOCSBTNMAP(joydev, argp, _IOC_SIZE(cmd));
595 
596 	case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
597 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
598 		return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len;
599 
600 	case JSIOCGNAME(0):
601 		name = dev->name;
602 		if (!name)
603 			return 0;
604 
605 		len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
606 		return copy_to_user(argp, name, len) ? -EFAULT : len;
607 	}
608 
609 	return -EINVAL;
610 }
611 
612 #ifdef CONFIG_COMPAT
613 static long joydev_compat_ioctl(struct file *file,
614 				unsigned int cmd, unsigned long arg)
615 {
616 	struct joydev_client *client = file->private_data;
617 	struct joydev *joydev = client->joydev;
618 	void __user *argp = (void __user *)arg;
619 	s32 tmp32;
620 	struct JS_DATA_SAVE_TYPE_32 ds32;
621 	int retval;
622 
623 	retval = mutex_lock_interruptible(&joydev->mutex);
624 	if (retval)
625 		return retval;
626 
627 	if (!joydev->exist) {
628 		retval = -ENODEV;
629 		goto out;
630 	}
631 
632 	switch (cmd) {
633 
634 	case JS_SET_TIMELIMIT:
635 		retval = get_user(tmp32, (s32 __user *) arg);
636 		if (retval == 0)
637 			joydev->glue.JS_TIMELIMIT = tmp32;
638 		break;
639 
640 	case JS_GET_TIMELIMIT:
641 		tmp32 = joydev->glue.JS_TIMELIMIT;
642 		retval = put_user(tmp32, (s32 __user *) arg);
643 		break;
644 
645 	case JS_SET_ALL:
646 		retval = copy_from_user(&ds32, argp,
647 					sizeof(ds32)) ? -EFAULT : 0;
648 		if (retval == 0) {
649 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
650 			joydev->glue.BUSY          = ds32.BUSY;
651 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
652 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
653 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
654 			joydev->glue.JS_CORR       = ds32.JS_CORR;
655 		}
656 		break;
657 
658 	case JS_GET_ALL:
659 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
660 		ds32.BUSY          = joydev->glue.BUSY;
661 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
662 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
663 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
664 		ds32.JS_CORR       = joydev->glue.JS_CORR;
665 
666 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
667 		break;
668 
669 	default:
670 		retval = joydev_ioctl_common(joydev, cmd, argp);
671 		break;
672 	}
673 
674  out:
675 	mutex_unlock(&joydev->mutex);
676 	return retval;
677 }
678 #endif /* CONFIG_COMPAT */
679 
680 static long joydev_ioctl(struct file *file,
681 			 unsigned int cmd, unsigned long arg)
682 {
683 	struct joydev_client *client = file->private_data;
684 	struct joydev *joydev = client->joydev;
685 	void __user *argp = (void __user *)arg;
686 	int retval;
687 
688 	retval = mutex_lock_interruptible(&joydev->mutex);
689 	if (retval)
690 		return retval;
691 
692 	if (!joydev->exist) {
693 		retval = -ENODEV;
694 		goto out;
695 	}
696 
697 	switch (cmd) {
698 
699 	case JS_SET_TIMELIMIT:
700 		retval = get_user(joydev->glue.JS_TIMELIMIT,
701 				  (long __user *) arg);
702 		break;
703 
704 	case JS_GET_TIMELIMIT:
705 		retval = put_user(joydev->glue.JS_TIMELIMIT,
706 				  (long __user *) arg);
707 		break;
708 
709 	case JS_SET_ALL:
710 		retval = copy_from_user(&joydev->glue, argp,
711 					sizeof(joydev->glue)) ? -EFAULT: 0;
712 		break;
713 
714 	case JS_GET_ALL:
715 		retval = copy_to_user(argp, &joydev->glue,
716 				      sizeof(joydev->glue)) ? -EFAULT : 0;
717 		break;
718 
719 	default:
720 		retval = joydev_ioctl_common(joydev, cmd, argp);
721 		break;
722 	}
723  out:
724 	mutex_unlock(&joydev->mutex);
725 	return retval;
726 }
727 
728 static const struct file_operations joydev_fops = {
729 	.owner		= THIS_MODULE,
730 	.read		= joydev_read,
731 	.poll		= joydev_poll,
732 	.open		= joydev_open,
733 	.release	= joydev_release,
734 	.unlocked_ioctl	= joydev_ioctl,
735 #ifdef CONFIG_COMPAT
736 	.compat_ioctl	= joydev_compat_ioctl,
737 #endif
738 	.fasync		= joydev_fasync,
739 };
740 
741 static int joydev_install_chrdev(struct joydev *joydev)
742 {
743 	joydev_table[joydev->minor] = joydev;
744 	return 0;
745 }
746 
747 static void joydev_remove_chrdev(struct joydev *joydev)
748 {
749 	mutex_lock(&joydev_table_mutex);
750 	joydev_table[joydev->minor] = NULL;
751 	mutex_unlock(&joydev_table_mutex);
752 }
753 
754 /*
755  * Mark device non-existant. This disables writes, ioctls and
756  * prevents new users from opening the device. Already posted
757  * blocking reads will stay, however new ones will fail.
758  */
759 static void joydev_mark_dead(struct joydev *joydev)
760 {
761 	mutex_lock(&joydev->mutex);
762 	joydev->exist = false;
763 	mutex_unlock(&joydev->mutex);
764 }
765 
766 static void joydev_cleanup(struct joydev *joydev)
767 {
768 	struct input_handle *handle = &joydev->handle;
769 
770 	joydev_mark_dead(joydev);
771 	joydev_hangup(joydev);
772 	joydev_remove_chrdev(joydev);
773 
774 	/* joydev is marked dead so noone else accesses joydev->open */
775 	if (joydev->open)
776 		input_close_device(handle);
777 }
778 
779 
780 static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
781 {
782 	/* Avoid touchpads and touchscreens */
783 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
784 		return false;
785 
786 	/* Avoid tablets, digitisers and similar devices */
787 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
788 		return false;
789 
790 	return true;
791 }
792 
793 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
794 			  const struct input_device_id *id)
795 {
796 	struct joydev *joydev;
797 	int i, j, t, minor;
798 	int error;
799 
800 	for (minor = 0; minor < JOYDEV_MINORS; minor++)
801 		if (!joydev_table[minor])
802 			break;
803 
804 	if (minor == JOYDEV_MINORS) {
805 		printk(KERN_ERR "joydev: no more free joydev devices\n");
806 		return -ENFILE;
807 	}
808 
809 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
810 	if (!joydev)
811 		return -ENOMEM;
812 
813 	INIT_LIST_HEAD(&joydev->client_list);
814 	spin_lock_init(&joydev->client_lock);
815 	mutex_init(&joydev->mutex);
816 	init_waitqueue_head(&joydev->wait);
817 
818 	dev_set_name(&joydev->dev, "js%d", minor);
819 	joydev->exist = true;
820 	joydev->minor = minor;
821 
822 	joydev->handle.dev = input_get_device(dev);
823 	joydev->handle.name = dev_name(&joydev->dev);
824 	joydev->handle.handler = handler;
825 	joydev->handle.private = joydev;
826 
827 	for (i = 0; i < ABS_CNT; i++)
828 		if (test_bit(i, dev->absbit)) {
829 			joydev->absmap[i] = joydev->nabs;
830 			joydev->abspam[joydev->nabs] = i;
831 			joydev->nabs++;
832 		}
833 
834 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
835 		if (test_bit(i + BTN_MISC, dev->keybit)) {
836 			joydev->keymap[i] = joydev->nkey;
837 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
838 			joydev->nkey++;
839 		}
840 
841 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
842 		if (test_bit(i + BTN_MISC, dev->keybit)) {
843 			joydev->keymap[i] = joydev->nkey;
844 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
845 			joydev->nkey++;
846 		}
847 
848 	for (i = 0; i < joydev->nabs; i++) {
849 		j = joydev->abspam[i];
850 		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {
851 			joydev->corr[i].type = JS_CORR_NONE;
852 			joydev->abs[i] = input_abs_get_val(dev, j);
853 			continue;
854 		}
855 		joydev->corr[i].type = JS_CORR_BROKEN;
856 		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
857 
858 		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
859 		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
860 		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);
861 
862 		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
863 			- 2 * input_abs_get_flat(dev, j);
864 		if (t) {
865 			joydev->corr[i].coef[2] = (1 << 29) / t;
866 			joydev->corr[i].coef[3] = (1 << 29) / t;
867 
868 			joydev->abs[i] =
869 				joydev_correct(input_abs_get_val(dev, j),
870 					       joydev->corr + i);
871 		}
872 	}
873 
874 	joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
875 	joydev->dev.class = &input_class;
876 	joydev->dev.parent = &dev->dev;
877 	joydev->dev.release = joydev_free;
878 	device_initialize(&joydev->dev);
879 
880 	error = input_register_handle(&joydev->handle);
881 	if (error)
882 		goto err_free_joydev;
883 
884 	error = joydev_install_chrdev(joydev);
885 	if (error)
886 		goto err_unregister_handle;
887 
888 	error = device_add(&joydev->dev);
889 	if (error)
890 		goto err_cleanup_joydev;
891 
892 	return 0;
893 
894  err_cleanup_joydev:
895 	joydev_cleanup(joydev);
896  err_unregister_handle:
897 	input_unregister_handle(&joydev->handle);
898  err_free_joydev:
899 	put_device(&joydev->dev);
900 	return error;
901 }
902 
903 static void joydev_disconnect(struct input_handle *handle)
904 {
905 	struct joydev *joydev = handle->private;
906 
907 	device_del(&joydev->dev);
908 	joydev_cleanup(joydev);
909 	input_unregister_handle(handle);
910 	put_device(&joydev->dev);
911 }
912 
913 static const struct input_device_id joydev_ids[] = {
914 	{
915 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
916 				INPUT_DEVICE_ID_MATCH_ABSBIT,
917 		.evbit = { BIT_MASK(EV_ABS) },
918 		.absbit = { BIT_MASK(ABS_X) },
919 	},
920 	{
921 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
922 				INPUT_DEVICE_ID_MATCH_ABSBIT,
923 		.evbit = { BIT_MASK(EV_ABS) },
924 		.absbit = { BIT_MASK(ABS_WHEEL) },
925 	},
926 	{
927 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
928 				INPUT_DEVICE_ID_MATCH_ABSBIT,
929 		.evbit = { BIT_MASK(EV_ABS) },
930 		.absbit = { BIT_MASK(ABS_THROTTLE) },
931 	},
932 	{
933 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
934 				INPUT_DEVICE_ID_MATCH_KEYBIT,
935 		.evbit = { BIT_MASK(EV_KEY) },
936 		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
937 	},
938 	{
939 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
940 				INPUT_DEVICE_ID_MATCH_KEYBIT,
941 		.evbit = { BIT_MASK(EV_KEY) },
942 		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
943 	},
944 	{
945 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
946 				INPUT_DEVICE_ID_MATCH_KEYBIT,
947 		.evbit = { BIT_MASK(EV_KEY) },
948 		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
949 	},
950 	{ }	/* Terminating entry */
951 };
952 
953 MODULE_DEVICE_TABLE(input, joydev_ids);
954 
955 static struct input_handler joydev_handler = {
956 	.event		= joydev_event,
957 	.match		= joydev_match,
958 	.connect	= joydev_connect,
959 	.disconnect	= joydev_disconnect,
960 	.fops		= &joydev_fops,
961 	.minor		= JOYDEV_MINOR_BASE,
962 	.name		= "joydev",
963 	.id_table	= joydev_ids,
964 };
965 
966 static int __init joydev_init(void)
967 {
968 	return input_register_handler(&joydev_handler);
969 }
970 
971 static void __exit joydev_exit(void)
972 {
973 	input_unregister_handler(&joydev_handler);
974 }
975 
976 module_init(joydev_init);
977 module_exit(joydev_exit);
978