xref: /linux/drivers/input/joydev.c (revision 95e9fd10f06cb5642028b6b851e32b8c8afb4571)
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <asm/io.h>
16 #include <linux/delay.h>
17 #include <linux/errno.h>
18 #include <linux/joystick.h>
19 #include <linux/input.h>
20 #include <linux/kernel.h>
21 #include <linux/major.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/mm.h>
25 #include <linux/miscdevice.h>
26 #include <linux/module.h>
27 #include <linux/poll.h>
28 #include <linux/init.h>
29 #include <linux/device.h>
30 
31 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
32 MODULE_DESCRIPTION("Joystick device interfaces");
33 MODULE_SUPPORTED_DEVICE("input/js");
34 MODULE_LICENSE("GPL");
35 
36 #define JOYDEV_MINOR_BASE	0
37 #define JOYDEV_MINORS		16
38 #define JOYDEV_BUFFER_SIZE	64
39 
40 struct joydev {
41 	int open;
42 	int minor;
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 	bool exist;
50 
51 	struct js_corr corr[ABS_CNT];
52 	struct JS_DATA_SAVE_TYPE glue;
53 	int nabs;
54 	int nkey;
55 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
56 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
57 	__u8 absmap[ABS_CNT];
58 	__u8 abspam[ABS_CNT];
59 	__s16 abs[ABS_CNT];
60 };
61 
62 struct joydev_client {
63 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
64 	int head;
65 	int tail;
66 	int startup;
67 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
68 	struct fasync_struct *fasync;
69 	struct joydev *joydev;
70 	struct list_head node;
71 };
72 
73 static struct joydev *joydev_table[JOYDEV_MINORS];
74 static DEFINE_MUTEX(joydev_table_mutex);
75 
76 static int joydev_correct(int value, struct js_corr *corr)
77 {
78 	switch (corr->type) {
79 
80 	case JS_CORR_NONE:
81 		break;
82 
83 	case JS_CORR_BROKEN:
84 		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
85 			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
86 			((corr->coef[2] * (value - corr->coef[0])) >> 14);
87 		break;
88 
89 	default:
90 		return 0;
91 	}
92 
93 	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
94 }
95 
96 static void joydev_pass_event(struct joydev_client *client,
97 			      struct js_event *event)
98 {
99 	struct joydev *joydev = client->joydev;
100 
101 	/*
102 	 * IRQs already disabled, just acquire the lock
103 	 */
104 	spin_lock(&client->buffer_lock);
105 
106 	client->buffer[client->head] = *event;
107 
108 	if (client->startup == joydev->nabs + joydev->nkey) {
109 		client->head++;
110 		client->head &= JOYDEV_BUFFER_SIZE - 1;
111 		if (client->tail == client->head)
112 			client->startup = 0;
113 	}
114 
115 	spin_unlock(&client->buffer_lock);
116 
117 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
118 }
119 
120 static void joydev_event(struct input_handle *handle,
121 			 unsigned int type, unsigned int code, int value)
122 {
123 	struct joydev *joydev = handle->private;
124 	struct joydev_client *client;
125 	struct js_event event;
126 
127 	switch (type) {
128 
129 	case EV_KEY:
130 		if (code < BTN_MISC || value == 2)
131 			return;
132 		event.type = JS_EVENT_BUTTON;
133 		event.number = joydev->keymap[code - BTN_MISC];
134 		event.value = value;
135 		break;
136 
137 	case EV_ABS:
138 		event.type = JS_EVENT_AXIS;
139 		event.number = joydev->absmap[code];
140 		event.value = joydev_correct(value,
141 					&joydev->corr[event.number]);
142 		if (event.value == joydev->abs[event.number])
143 			return;
144 		joydev->abs[event.number] = event.value;
145 		break;
146 
147 	default:
148 		return;
149 	}
150 
151 	event.time = jiffies_to_msecs(jiffies);
152 
153 	rcu_read_lock();
154 	list_for_each_entry_rcu(client, &joydev->client_list, node)
155 		joydev_pass_event(client, &event);
156 	rcu_read_unlock();
157 
158 	wake_up_interruptible(&joydev->wait);
159 }
160 
161 static int joydev_fasync(int fd, struct file *file, int on)
162 {
163 	struct joydev_client *client = file->private_data;
164 
165 	return fasync_helper(fd, file, on, &client->fasync);
166 }
167 
168 static void joydev_free(struct device *dev)
169 {
170 	struct joydev *joydev = container_of(dev, struct joydev, dev);
171 
172 	input_put_device(joydev->handle.dev);
173 	kfree(joydev);
174 }
175 
176 static void joydev_attach_client(struct joydev *joydev,
177 				 struct joydev_client *client)
178 {
179 	spin_lock(&joydev->client_lock);
180 	list_add_tail_rcu(&client->node, &joydev->client_list);
181 	spin_unlock(&joydev->client_lock);
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 	for (i = 0; i < joydev->nabs; i++)
487 		joydev->absmap[joydev->abspam[i]] = i;
488 
489  out:
490 	kfree(abspam);
491 	return retval;
492 }
493 
494 static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
495 				      void __user *argp, size_t len)
496 {
497 	__u16 *keypam;
498 	int i;
499 	int retval = 0;
500 
501 	len = min(len, sizeof(joydev->keypam));
502 
503 	/* Validate the map. */
504 	keypam = kmalloc(len, GFP_KERNEL);
505 	if (!keypam)
506 		return -ENOMEM;
507 
508 	if (copy_from_user(keypam, argp, len)) {
509 		retval = -EFAULT;
510 		goto out;
511 	}
512 
513 	for (i = 0; i < joydev->nkey; i++) {
514 		if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
515 			retval = -EINVAL;
516 			goto out;
517 		}
518 	}
519 
520 	memcpy(joydev->keypam, keypam, len);
521 
522 	for (i = 0; i < joydev->nkey; i++)
523 		joydev->keymap[keypam[i] - BTN_MISC] = i;
524 
525  out:
526 	kfree(keypam);
527 	return retval;
528 }
529 
530 
531 static int joydev_ioctl_common(struct joydev *joydev,
532 				unsigned int cmd, void __user *argp)
533 {
534 	struct input_dev *dev = joydev->handle.dev;
535 	size_t len;
536 	int i;
537 	const char *name;
538 
539 	/* Process fixed-sized commands. */
540 	switch (cmd) {
541 
542 	case JS_SET_CAL:
543 		return copy_from_user(&joydev->glue.JS_CORR, argp,
544 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
545 
546 	case JS_GET_CAL:
547 		return copy_to_user(argp, &joydev->glue.JS_CORR,
548 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
549 
550 	case JS_SET_TIMEOUT:
551 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
552 
553 	case JS_GET_TIMEOUT:
554 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
555 
556 	case JSIOCGVERSION:
557 		return put_user(JS_VERSION, (__u32 __user *) argp);
558 
559 	case JSIOCGAXES:
560 		return put_user(joydev->nabs, (__u8 __user *) argp);
561 
562 	case JSIOCGBUTTONS:
563 		return put_user(joydev->nkey, (__u8 __user *) argp);
564 
565 	case JSIOCSCORR:
566 		if (copy_from_user(joydev->corr, argp,
567 			      sizeof(joydev->corr[0]) * joydev->nabs))
568 			return -EFAULT;
569 
570 		for (i = 0; i < joydev->nabs; i++) {
571 			int val = input_abs_get_val(dev, joydev->abspam[i]);
572 			joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
573 		}
574 		return 0;
575 
576 	case JSIOCGCORR:
577 		return copy_to_user(argp, joydev->corr,
578 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
579 
580 	}
581 
582 	/*
583 	 * Process variable-sized commands (the axis and button map commands
584 	 * are considered variable-sized to decouple them from the values of
585 	 * ABS_MAX and KEY_MAX).
586 	 */
587 	switch (cmd & ~IOCSIZE_MASK) {
588 
589 	case (JSIOCSAXMAP & ~IOCSIZE_MASK):
590 		return joydev_handle_JSIOCSAXMAP(joydev, argp, _IOC_SIZE(cmd));
591 
592 	case (JSIOCGAXMAP & ~IOCSIZE_MASK):
593 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
594 		return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len;
595 
596 	case (JSIOCSBTNMAP & ~IOCSIZE_MASK):
597 		return joydev_handle_JSIOCSBTNMAP(joydev, argp, _IOC_SIZE(cmd));
598 
599 	case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
600 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
601 		return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len;
602 
603 	case JSIOCGNAME(0):
604 		name = dev->name;
605 		if (!name)
606 			return 0;
607 
608 		len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
609 		return copy_to_user(argp, name, len) ? -EFAULT : len;
610 	}
611 
612 	return -EINVAL;
613 }
614 
615 #ifdef CONFIG_COMPAT
616 static long joydev_compat_ioctl(struct file *file,
617 				unsigned int cmd, unsigned long arg)
618 {
619 	struct joydev_client *client = file->private_data;
620 	struct joydev *joydev = client->joydev;
621 	void __user *argp = (void __user *)arg;
622 	s32 tmp32;
623 	struct JS_DATA_SAVE_TYPE_32 ds32;
624 	int retval;
625 
626 	retval = mutex_lock_interruptible(&joydev->mutex);
627 	if (retval)
628 		return retval;
629 
630 	if (!joydev->exist) {
631 		retval = -ENODEV;
632 		goto out;
633 	}
634 
635 	switch (cmd) {
636 
637 	case JS_SET_TIMELIMIT:
638 		retval = get_user(tmp32, (s32 __user *) arg);
639 		if (retval == 0)
640 			joydev->glue.JS_TIMELIMIT = tmp32;
641 		break;
642 
643 	case JS_GET_TIMELIMIT:
644 		tmp32 = joydev->glue.JS_TIMELIMIT;
645 		retval = put_user(tmp32, (s32 __user *) arg);
646 		break;
647 
648 	case JS_SET_ALL:
649 		retval = copy_from_user(&ds32, argp,
650 					sizeof(ds32)) ? -EFAULT : 0;
651 		if (retval == 0) {
652 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
653 			joydev->glue.BUSY          = ds32.BUSY;
654 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
655 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
656 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
657 			joydev->glue.JS_CORR       = ds32.JS_CORR;
658 		}
659 		break;
660 
661 	case JS_GET_ALL:
662 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
663 		ds32.BUSY          = joydev->glue.BUSY;
664 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
665 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
666 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
667 		ds32.JS_CORR       = joydev->glue.JS_CORR;
668 
669 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
670 		break;
671 
672 	default:
673 		retval = joydev_ioctl_common(joydev, cmd, argp);
674 		break;
675 	}
676 
677  out:
678 	mutex_unlock(&joydev->mutex);
679 	return retval;
680 }
681 #endif /* CONFIG_COMPAT */
682 
683 static long joydev_ioctl(struct file *file,
684 			 unsigned int cmd, unsigned long arg)
685 {
686 	struct joydev_client *client = file->private_data;
687 	struct joydev *joydev = client->joydev;
688 	void __user *argp = (void __user *)arg;
689 	int retval;
690 
691 	retval = mutex_lock_interruptible(&joydev->mutex);
692 	if (retval)
693 		return retval;
694 
695 	if (!joydev->exist) {
696 		retval = -ENODEV;
697 		goto out;
698 	}
699 
700 	switch (cmd) {
701 
702 	case JS_SET_TIMELIMIT:
703 		retval = get_user(joydev->glue.JS_TIMELIMIT,
704 				  (long __user *) arg);
705 		break;
706 
707 	case JS_GET_TIMELIMIT:
708 		retval = put_user(joydev->glue.JS_TIMELIMIT,
709 				  (long __user *) arg);
710 		break;
711 
712 	case JS_SET_ALL:
713 		retval = copy_from_user(&joydev->glue, argp,
714 					sizeof(joydev->glue)) ? -EFAULT: 0;
715 		break;
716 
717 	case JS_GET_ALL:
718 		retval = copy_to_user(argp, &joydev->glue,
719 				      sizeof(joydev->glue)) ? -EFAULT : 0;
720 		break;
721 
722 	default:
723 		retval = joydev_ioctl_common(joydev, cmd, argp);
724 		break;
725 	}
726  out:
727 	mutex_unlock(&joydev->mutex);
728 	return retval;
729 }
730 
731 static const struct file_operations joydev_fops = {
732 	.owner		= THIS_MODULE,
733 	.read		= joydev_read,
734 	.poll		= joydev_poll,
735 	.open		= joydev_open,
736 	.release	= joydev_release,
737 	.unlocked_ioctl	= joydev_ioctl,
738 #ifdef CONFIG_COMPAT
739 	.compat_ioctl	= joydev_compat_ioctl,
740 #endif
741 	.fasync		= joydev_fasync,
742 	.llseek		= no_llseek,
743 };
744 
745 static int joydev_install_chrdev(struct joydev *joydev)
746 {
747 	joydev_table[joydev->minor] = joydev;
748 	return 0;
749 }
750 
751 static void joydev_remove_chrdev(struct joydev *joydev)
752 {
753 	mutex_lock(&joydev_table_mutex);
754 	joydev_table[joydev->minor] = NULL;
755 	mutex_unlock(&joydev_table_mutex);
756 }
757 
758 /*
759  * Mark device non-existent. This disables writes, ioctls and
760  * prevents new users from opening the device. Already posted
761  * blocking reads will stay, however new ones will fail.
762  */
763 static void joydev_mark_dead(struct joydev *joydev)
764 {
765 	mutex_lock(&joydev->mutex);
766 	joydev->exist = false;
767 	mutex_unlock(&joydev->mutex);
768 }
769 
770 static void joydev_cleanup(struct joydev *joydev)
771 {
772 	struct input_handle *handle = &joydev->handle;
773 
774 	joydev_mark_dead(joydev);
775 	joydev_hangup(joydev);
776 	joydev_remove_chrdev(joydev);
777 
778 	/* joydev is marked dead so no one else accesses joydev->open */
779 	if (joydev->open)
780 		input_close_device(handle);
781 }
782 
783 
784 static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
785 {
786 	/* Avoid touchpads and touchscreens */
787 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
788 		return false;
789 
790 	/* Avoid tablets, digitisers and similar devices */
791 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
792 		return false;
793 
794 	return true;
795 }
796 
797 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
798 			  const struct input_device_id *id)
799 {
800 	struct joydev *joydev;
801 	int i, j, t, minor;
802 	int error;
803 
804 	for (minor = 0; minor < JOYDEV_MINORS; minor++)
805 		if (!joydev_table[minor])
806 			break;
807 
808 	if (minor == JOYDEV_MINORS) {
809 		pr_err("no more free joydev devices\n");
810 		return -ENFILE;
811 	}
812 
813 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
814 	if (!joydev)
815 		return -ENOMEM;
816 
817 	INIT_LIST_HEAD(&joydev->client_list);
818 	spin_lock_init(&joydev->client_lock);
819 	mutex_init(&joydev->mutex);
820 	init_waitqueue_head(&joydev->wait);
821 
822 	dev_set_name(&joydev->dev, "js%d", minor);
823 	joydev->exist = true;
824 	joydev->minor = minor;
825 
826 	joydev->handle.dev = input_get_device(dev);
827 	joydev->handle.name = dev_name(&joydev->dev);
828 	joydev->handle.handler = handler;
829 	joydev->handle.private = joydev;
830 
831 	for (i = 0; i < ABS_CNT; i++)
832 		if (test_bit(i, dev->absbit)) {
833 			joydev->absmap[i] = joydev->nabs;
834 			joydev->abspam[joydev->nabs] = i;
835 			joydev->nabs++;
836 		}
837 
838 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
839 		if (test_bit(i + BTN_MISC, dev->keybit)) {
840 			joydev->keymap[i] = joydev->nkey;
841 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
842 			joydev->nkey++;
843 		}
844 
845 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
846 		if (test_bit(i + BTN_MISC, dev->keybit)) {
847 			joydev->keymap[i] = joydev->nkey;
848 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
849 			joydev->nkey++;
850 		}
851 
852 	for (i = 0; i < joydev->nabs; i++) {
853 		j = joydev->abspam[i];
854 		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {
855 			joydev->corr[i].type = JS_CORR_NONE;
856 			joydev->abs[i] = input_abs_get_val(dev, j);
857 			continue;
858 		}
859 		joydev->corr[i].type = JS_CORR_BROKEN;
860 		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
861 
862 		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
863 		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
864 		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);
865 
866 		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
867 			- 2 * input_abs_get_flat(dev, j);
868 		if (t) {
869 			joydev->corr[i].coef[2] = (1 << 29) / t;
870 			joydev->corr[i].coef[3] = (1 << 29) / t;
871 
872 			joydev->abs[i] =
873 				joydev_correct(input_abs_get_val(dev, j),
874 					       joydev->corr + i);
875 		}
876 	}
877 
878 	joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
879 	joydev->dev.class = &input_class;
880 	joydev->dev.parent = &dev->dev;
881 	joydev->dev.release = joydev_free;
882 	device_initialize(&joydev->dev);
883 
884 	error = input_register_handle(&joydev->handle);
885 	if (error)
886 		goto err_free_joydev;
887 
888 	error = joydev_install_chrdev(joydev);
889 	if (error)
890 		goto err_unregister_handle;
891 
892 	error = device_add(&joydev->dev);
893 	if (error)
894 		goto err_cleanup_joydev;
895 
896 	return 0;
897 
898  err_cleanup_joydev:
899 	joydev_cleanup(joydev);
900  err_unregister_handle:
901 	input_unregister_handle(&joydev->handle);
902  err_free_joydev:
903 	put_device(&joydev->dev);
904 	return error;
905 }
906 
907 static void joydev_disconnect(struct input_handle *handle)
908 {
909 	struct joydev *joydev = handle->private;
910 
911 	device_del(&joydev->dev);
912 	joydev_cleanup(joydev);
913 	input_unregister_handle(handle);
914 	put_device(&joydev->dev);
915 }
916 
917 static const struct input_device_id joydev_ids[] = {
918 	{
919 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
920 				INPUT_DEVICE_ID_MATCH_ABSBIT,
921 		.evbit = { BIT_MASK(EV_ABS) },
922 		.absbit = { BIT_MASK(ABS_X) },
923 	},
924 	{
925 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
926 				INPUT_DEVICE_ID_MATCH_ABSBIT,
927 		.evbit = { BIT_MASK(EV_ABS) },
928 		.absbit = { BIT_MASK(ABS_WHEEL) },
929 	},
930 	{
931 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
932 				INPUT_DEVICE_ID_MATCH_ABSBIT,
933 		.evbit = { BIT_MASK(EV_ABS) },
934 		.absbit = { BIT_MASK(ABS_THROTTLE) },
935 	},
936 	{
937 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
938 				INPUT_DEVICE_ID_MATCH_KEYBIT,
939 		.evbit = { BIT_MASK(EV_KEY) },
940 		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
941 	},
942 	{
943 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
944 				INPUT_DEVICE_ID_MATCH_KEYBIT,
945 		.evbit = { BIT_MASK(EV_KEY) },
946 		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
947 	},
948 	{
949 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
950 				INPUT_DEVICE_ID_MATCH_KEYBIT,
951 		.evbit = { BIT_MASK(EV_KEY) },
952 		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
953 	},
954 	{ }	/* Terminating entry */
955 };
956 
957 MODULE_DEVICE_TABLE(input, joydev_ids);
958 
959 static struct input_handler joydev_handler = {
960 	.event		= joydev_event,
961 	.match		= joydev_match,
962 	.connect	= joydev_connect,
963 	.disconnect	= joydev_disconnect,
964 	.fops		= &joydev_fops,
965 	.minor		= JOYDEV_MINOR_BASE,
966 	.name		= "joydev",
967 	.id_table	= joydev_ids,
968 };
969 
970 static int __init joydev_init(void)
971 {
972 	return input_register_handler(&joydev_handler);
973 }
974 
975 static void __exit joydev_exit(void)
976 {
977 	input_unregister_handler(&joydev_handler);
978 }
979 
980 module_init(joydev_init);
981 module_exit(joydev_exit);
982