xref: /linux/drivers/input/joydev.c (revision f884ab15afdc5514e88105c92a4e2e1e6539869a)
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 #include <linux/cdev.h>
31 
32 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
33 MODULE_DESCRIPTION("Joystick device interfaces");
34 MODULE_SUPPORTED_DEVICE("input/js");
35 MODULE_LICENSE("GPL");
36 
37 #define JOYDEV_MINOR_BASE	0
38 #define JOYDEV_MINORS		16
39 #define JOYDEV_BUFFER_SIZE	64
40 
41 struct joydev {
42 	int open;
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 	struct cdev cdev;
50 	bool exist;
51 
52 	struct js_corr corr[ABS_CNT];
53 	struct JS_DATA_SAVE_TYPE glue;
54 	int nabs;
55 	int nkey;
56 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
57 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
58 	__u8 absmap[ABS_CNT];
59 	__u8 abspam[ABS_CNT];
60 	__s16 abs[ABS_CNT];
61 };
62 
63 struct joydev_client {
64 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
65 	int head;
66 	int tail;
67 	int startup;
68 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
69 	struct fasync_struct *fasync;
70 	struct joydev *joydev;
71 	struct list_head node;
72 };
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 }
181 
182 static void joydev_detach_client(struct joydev *joydev,
183 				 struct joydev_client *client)
184 {
185 	spin_lock(&joydev->client_lock);
186 	list_del_rcu(&client->node);
187 	spin_unlock(&joydev->client_lock);
188 	synchronize_rcu();
189 }
190 
191 static int joydev_open_device(struct joydev *joydev)
192 {
193 	int retval;
194 
195 	retval = mutex_lock_interruptible(&joydev->mutex);
196 	if (retval)
197 		return retval;
198 
199 	if (!joydev->exist)
200 		retval = -ENODEV;
201 	else if (!joydev->open++) {
202 		retval = input_open_device(&joydev->handle);
203 		if (retval)
204 			joydev->open--;
205 	}
206 
207 	mutex_unlock(&joydev->mutex);
208 	return retval;
209 }
210 
211 static void joydev_close_device(struct joydev *joydev)
212 {
213 	mutex_lock(&joydev->mutex);
214 
215 	if (joydev->exist && !--joydev->open)
216 		input_close_device(&joydev->handle);
217 
218 	mutex_unlock(&joydev->mutex);
219 }
220 
221 /*
222  * Wake up users waiting for IO so they can disconnect from
223  * dead device.
224  */
225 static void joydev_hangup(struct joydev *joydev)
226 {
227 	struct joydev_client *client;
228 
229 	spin_lock(&joydev->client_lock);
230 	list_for_each_entry(client, &joydev->client_list, node)
231 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
232 	spin_unlock(&joydev->client_lock);
233 
234 	wake_up_interruptible(&joydev->wait);
235 }
236 
237 static int joydev_release(struct inode *inode, struct file *file)
238 {
239 	struct joydev_client *client = file->private_data;
240 	struct joydev *joydev = client->joydev;
241 
242 	joydev_detach_client(joydev, client);
243 	kfree(client);
244 
245 	joydev_close_device(joydev);
246 
247 	return 0;
248 }
249 
250 static int joydev_open(struct inode *inode, struct file *file)
251 {
252 	struct joydev *joydev =
253 			container_of(inode->i_cdev, struct joydev, cdev);
254 	struct joydev_client *client;
255 	int error;
256 
257 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
258 	if (!client)
259 		return -ENOMEM;
260 
261 	spin_lock_init(&client->buffer_lock);
262 	client->joydev = joydev;
263 	joydev_attach_client(joydev, client);
264 
265 	error = joydev_open_device(joydev);
266 	if (error)
267 		goto err_free_client;
268 
269 	file->private_data = client;
270 	nonseekable_open(inode, file);
271 
272 	return 0;
273 
274  err_free_client:
275 	joydev_detach_client(joydev, client);
276 	kfree(client);
277 	return error;
278 }
279 
280 static int joydev_generate_startup_event(struct joydev_client *client,
281 					 struct input_dev *input,
282 					 struct js_event *event)
283 {
284 	struct joydev *joydev = client->joydev;
285 	int have_event;
286 
287 	spin_lock_irq(&client->buffer_lock);
288 
289 	have_event = client->startup < joydev->nabs + joydev->nkey;
290 
291 	if (have_event) {
292 
293 		event->time = jiffies_to_msecs(jiffies);
294 		if (client->startup < joydev->nkey) {
295 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
296 			event->number = client->startup;
297 			event->value = !!test_bit(joydev->keypam[event->number],
298 						  input->key);
299 		} else {
300 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
301 			event->number = client->startup - joydev->nkey;
302 			event->value = joydev->abs[event->number];
303 		}
304 		client->startup++;
305 	}
306 
307 	spin_unlock_irq(&client->buffer_lock);
308 
309 	return have_event;
310 }
311 
312 static int joydev_fetch_next_event(struct joydev_client *client,
313 				   struct js_event *event)
314 {
315 	int have_event;
316 
317 	spin_lock_irq(&client->buffer_lock);
318 
319 	have_event = client->head != client->tail;
320 	if (have_event) {
321 		*event = client->buffer[client->tail++];
322 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
323 	}
324 
325 	spin_unlock_irq(&client->buffer_lock);
326 
327 	return have_event;
328 }
329 
330 /*
331  * Old joystick interface
332  */
333 static ssize_t joydev_0x_read(struct joydev_client *client,
334 			      struct input_dev *input,
335 			      char __user *buf)
336 {
337 	struct joydev *joydev = client->joydev;
338 	struct JS_DATA_TYPE data;
339 	int i;
340 
341 	spin_lock_irq(&input->event_lock);
342 
343 	/*
344 	 * Get device state
345 	 */
346 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
347 		data.buttons |=
348 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
349 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
350 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
351 
352 	/*
353 	 * Reset reader's event queue
354 	 */
355 	spin_lock(&client->buffer_lock);
356 	client->startup = 0;
357 	client->tail = client->head;
358 	spin_unlock(&client->buffer_lock);
359 
360 	spin_unlock_irq(&input->event_lock);
361 
362 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
363 		return -EFAULT;
364 
365 	return sizeof(struct JS_DATA_TYPE);
366 }
367 
368 static inline int joydev_data_pending(struct joydev_client *client)
369 {
370 	struct joydev *joydev = client->joydev;
371 
372 	return client->startup < joydev->nabs + joydev->nkey ||
373 		client->head != client->tail;
374 }
375 
376 static ssize_t joydev_read(struct file *file, char __user *buf,
377 			   size_t count, loff_t *ppos)
378 {
379 	struct joydev_client *client = file->private_data;
380 	struct joydev *joydev = client->joydev;
381 	struct input_dev *input = joydev->handle.dev;
382 	struct js_event event;
383 	int retval;
384 
385 	if (!joydev->exist)
386 		return -ENODEV;
387 
388 	if (count < sizeof(struct js_event))
389 		return -EINVAL;
390 
391 	if (count == sizeof(struct JS_DATA_TYPE))
392 		return joydev_0x_read(client, input, buf);
393 
394 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
395 		return -EAGAIN;
396 
397 	retval = wait_event_interruptible(joydev->wait,
398 			!joydev->exist || joydev_data_pending(client));
399 	if (retval)
400 		return retval;
401 
402 	if (!joydev->exist)
403 		return -ENODEV;
404 
405 	while (retval + sizeof(struct js_event) <= count &&
406 	       joydev_generate_startup_event(client, input, &event)) {
407 
408 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
409 			return -EFAULT;
410 
411 		retval += sizeof(struct js_event);
412 	}
413 
414 	while (retval + sizeof(struct js_event) <= count &&
415 	       joydev_fetch_next_event(client, &event)) {
416 
417 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
418 			return -EFAULT;
419 
420 		retval += sizeof(struct js_event);
421 	}
422 
423 	return retval;
424 }
425 
426 /* No kernel lock - fine */
427 static unsigned int joydev_poll(struct file *file, poll_table *wait)
428 {
429 	struct joydev_client *client = file->private_data;
430 	struct joydev *joydev = client->joydev;
431 
432 	poll_wait(file, &joydev->wait, wait);
433 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
434 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
435 }
436 
437 static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
438 				     void __user *argp, size_t len)
439 {
440 	__u8 *abspam;
441 	int i;
442 	int retval = 0;
443 
444 	len = min(len, sizeof(joydev->abspam));
445 
446 	/* Validate the map. */
447 	abspam = kmalloc(len, GFP_KERNEL);
448 	if (!abspam)
449 		return -ENOMEM;
450 
451 	if (copy_from_user(abspam, argp, len)) {
452 		retval = -EFAULT;
453 		goto out;
454 	}
455 
456 	for (i = 0; i < joydev->nabs; i++) {
457 		if (abspam[i] > ABS_MAX) {
458 			retval = -EINVAL;
459 			goto out;
460 		}
461 	}
462 
463 	memcpy(joydev->abspam, abspam, len);
464 
465 	for (i = 0; i < joydev->nabs; i++)
466 		joydev->absmap[joydev->abspam[i]] = i;
467 
468  out:
469 	kfree(abspam);
470 	return retval;
471 }
472 
473 static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
474 				      void __user *argp, size_t len)
475 {
476 	__u16 *keypam;
477 	int i;
478 	int retval = 0;
479 
480 	len = min(len, sizeof(joydev->keypam));
481 
482 	/* Validate the map. */
483 	keypam = kmalloc(len, GFP_KERNEL);
484 	if (!keypam)
485 		return -ENOMEM;
486 
487 	if (copy_from_user(keypam, argp, len)) {
488 		retval = -EFAULT;
489 		goto out;
490 	}
491 
492 	for (i = 0; i < joydev->nkey; i++) {
493 		if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
494 			retval = -EINVAL;
495 			goto out;
496 		}
497 	}
498 
499 	memcpy(joydev->keypam, keypam, len);
500 
501 	for (i = 0; i < joydev->nkey; i++)
502 		joydev->keymap[keypam[i] - BTN_MISC] = i;
503 
504  out:
505 	kfree(keypam);
506 	return retval;
507 }
508 
509 
510 static int joydev_ioctl_common(struct joydev *joydev,
511 				unsigned int cmd, void __user *argp)
512 {
513 	struct input_dev *dev = joydev->handle.dev;
514 	size_t len;
515 	int i;
516 	const char *name;
517 
518 	/* Process fixed-sized commands. */
519 	switch (cmd) {
520 
521 	case JS_SET_CAL:
522 		return copy_from_user(&joydev->glue.JS_CORR, argp,
523 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
524 
525 	case JS_GET_CAL:
526 		return copy_to_user(argp, &joydev->glue.JS_CORR,
527 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
528 
529 	case JS_SET_TIMEOUT:
530 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
531 
532 	case JS_GET_TIMEOUT:
533 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
534 
535 	case JSIOCGVERSION:
536 		return put_user(JS_VERSION, (__u32 __user *) argp);
537 
538 	case JSIOCGAXES:
539 		return put_user(joydev->nabs, (__u8 __user *) argp);
540 
541 	case JSIOCGBUTTONS:
542 		return put_user(joydev->nkey, (__u8 __user *) argp);
543 
544 	case JSIOCSCORR:
545 		if (copy_from_user(joydev->corr, argp,
546 			      sizeof(joydev->corr[0]) * joydev->nabs))
547 			return -EFAULT;
548 
549 		for (i = 0; i < joydev->nabs; i++) {
550 			int val = input_abs_get_val(dev, joydev->abspam[i]);
551 			joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
552 		}
553 		return 0;
554 
555 	case JSIOCGCORR:
556 		return copy_to_user(argp, joydev->corr,
557 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
558 
559 	}
560 
561 	/*
562 	 * Process variable-sized commands (the axis and button map commands
563 	 * are considered variable-sized to decouple them from the values of
564 	 * ABS_MAX and KEY_MAX).
565 	 */
566 	switch (cmd & ~IOCSIZE_MASK) {
567 
568 	case (JSIOCSAXMAP & ~IOCSIZE_MASK):
569 		return joydev_handle_JSIOCSAXMAP(joydev, argp, _IOC_SIZE(cmd));
570 
571 	case (JSIOCGAXMAP & ~IOCSIZE_MASK):
572 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
573 		return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len;
574 
575 	case (JSIOCSBTNMAP & ~IOCSIZE_MASK):
576 		return joydev_handle_JSIOCSBTNMAP(joydev, argp, _IOC_SIZE(cmd));
577 
578 	case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
579 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
580 		return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len;
581 
582 	case JSIOCGNAME(0):
583 		name = dev->name;
584 		if (!name)
585 			return 0;
586 
587 		len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
588 		return copy_to_user(argp, name, len) ? -EFAULT : len;
589 	}
590 
591 	return -EINVAL;
592 }
593 
594 #ifdef CONFIG_COMPAT
595 static long joydev_compat_ioctl(struct file *file,
596 				unsigned int cmd, unsigned long arg)
597 {
598 	struct joydev_client *client = file->private_data;
599 	struct joydev *joydev = client->joydev;
600 	void __user *argp = (void __user *)arg;
601 	s32 tmp32;
602 	struct JS_DATA_SAVE_TYPE_32 ds32;
603 	int retval;
604 
605 	retval = mutex_lock_interruptible(&joydev->mutex);
606 	if (retval)
607 		return retval;
608 
609 	if (!joydev->exist) {
610 		retval = -ENODEV;
611 		goto out;
612 	}
613 
614 	switch (cmd) {
615 
616 	case JS_SET_TIMELIMIT:
617 		retval = get_user(tmp32, (s32 __user *) arg);
618 		if (retval == 0)
619 			joydev->glue.JS_TIMELIMIT = tmp32;
620 		break;
621 
622 	case JS_GET_TIMELIMIT:
623 		tmp32 = joydev->glue.JS_TIMELIMIT;
624 		retval = put_user(tmp32, (s32 __user *) arg);
625 		break;
626 
627 	case JS_SET_ALL:
628 		retval = copy_from_user(&ds32, argp,
629 					sizeof(ds32)) ? -EFAULT : 0;
630 		if (retval == 0) {
631 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
632 			joydev->glue.BUSY          = ds32.BUSY;
633 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
634 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
635 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
636 			joydev->glue.JS_CORR       = ds32.JS_CORR;
637 		}
638 		break;
639 
640 	case JS_GET_ALL:
641 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
642 		ds32.BUSY          = joydev->glue.BUSY;
643 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
644 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
645 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
646 		ds32.JS_CORR       = joydev->glue.JS_CORR;
647 
648 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
649 		break;
650 
651 	default:
652 		retval = joydev_ioctl_common(joydev, cmd, argp);
653 		break;
654 	}
655 
656  out:
657 	mutex_unlock(&joydev->mutex);
658 	return retval;
659 }
660 #endif /* CONFIG_COMPAT */
661 
662 static long joydev_ioctl(struct file *file,
663 			 unsigned int cmd, unsigned long arg)
664 {
665 	struct joydev_client *client = file->private_data;
666 	struct joydev *joydev = client->joydev;
667 	void __user *argp = (void __user *)arg;
668 	int retval;
669 
670 	retval = mutex_lock_interruptible(&joydev->mutex);
671 	if (retval)
672 		return retval;
673 
674 	if (!joydev->exist) {
675 		retval = -ENODEV;
676 		goto out;
677 	}
678 
679 	switch (cmd) {
680 
681 	case JS_SET_TIMELIMIT:
682 		retval = get_user(joydev->glue.JS_TIMELIMIT,
683 				  (long __user *) arg);
684 		break;
685 
686 	case JS_GET_TIMELIMIT:
687 		retval = put_user(joydev->glue.JS_TIMELIMIT,
688 				  (long __user *) arg);
689 		break;
690 
691 	case JS_SET_ALL:
692 		retval = copy_from_user(&joydev->glue, argp,
693 					sizeof(joydev->glue)) ? -EFAULT : 0;
694 		break;
695 
696 	case JS_GET_ALL:
697 		retval = copy_to_user(argp, &joydev->glue,
698 				      sizeof(joydev->glue)) ? -EFAULT : 0;
699 		break;
700 
701 	default:
702 		retval = joydev_ioctl_common(joydev, cmd, argp);
703 		break;
704 	}
705  out:
706 	mutex_unlock(&joydev->mutex);
707 	return retval;
708 }
709 
710 static const struct file_operations joydev_fops = {
711 	.owner		= THIS_MODULE,
712 	.read		= joydev_read,
713 	.poll		= joydev_poll,
714 	.open		= joydev_open,
715 	.release	= joydev_release,
716 	.unlocked_ioctl	= joydev_ioctl,
717 #ifdef CONFIG_COMPAT
718 	.compat_ioctl	= joydev_compat_ioctl,
719 #endif
720 	.fasync		= joydev_fasync,
721 	.llseek		= no_llseek,
722 };
723 
724 /*
725  * Mark device non-existent. This disables writes, ioctls and
726  * prevents new users from opening the device. Already posted
727  * blocking reads will stay, however new ones will fail.
728  */
729 static void joydev_mark_dead(struct joydev *joydev)
730 {
731 	mutex_lock(&joydev->mutex);
732 	joydev->exist = false;
733 	mutex_unlock(&joydev->mutex);
734 }
735 
736 static void joydev_cleanup(struct joydev *joydev)
737 {
738 	struct input_handle *handle = &joydev->handle;
739 
740 	joydev_mark_dead(joydev);
741 	joydev_hangup(joydev);
742 
743 	cdev_del(&joydev->cdev);
744 
745 	/* joydev is marked dead so no one else accesses joydev->open */
746 	if (joydev->open)
747 		input_close_device(handle);
748 }
749 
750 
751 static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
752 {
753 	/* Avoid touchpads and touchscreens */
754 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
755 		return false;
756 
757 	/* Avoid tablets, digitisers and similar devices */
758 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
759 		return false;
760 
761 	return true;
762 }
763 
764 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
765 			  const struct input_device_id *id)
766 {
767 	struct joydev *joydev;
768 	int i, j, t, minor, dev_no;
769 	int error;
770 
771 	minor = input_get_new_minor(JOYDEV_MINOR_BASE, JOYDEV_MINORS, true);
772 	if (minor < 0) {
773 		error = minor;
774 		pr_err("failed to reserve new minor: %d\n", error);
775 		return error;
776 	}
777 
778 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
779 	if (!joydev) {
780 		error = -ENOMEM;
781 		goto err_free_minor;
782 	}
783 
784 	INIT_LIST_HEAD(&joydev->client_list);
785 	spin_lock_init(&joydev->client_lock);
786 	mutex_init(&joydev->mutex);
787 	init_waitqueue_head(&joydev->wait);
788 	joydev->exist = true;
789 
790 	dev_no = minor;
791 	/* Normalize device number if it falls into legacy range */
792 	if (dev_no < JOYDEV_MINOR_BASE + JOYDEV_MINORS)
793 		dev_no -= JOYDEV_MINOR_BASE;
794 	dev_set_name(&joydev->dev, "js%d", dev_no);
795 
796 	joydev->handle.dev = input_get_device(dev);
797 	joydev->handle.name = dev_name(&joydev->dev);
798 	joydev->handle.handler = handler;
799 	joydev->handle.private = joydev;
800 
801 	for (i = 0; i < ABS_CNT; i++)
802 		if (test_bit(i, dev->absbit)) {
803 			joydev->absmap[i] = joydev->nabs;
804 			joydev->abspam[joydev->nabs] = i;
805 			joydev->nabs++;
806 		}
807 
808 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
809 		if (test_bit(i + BTN_MISC, dev->keybit)) {
810 			joydev->keymap[i] = joydev->nkey;
811 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
812 			joydev->nkey++;
813 		}
814 
815 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
816 		if (test_bit(i + BTN_MISC, dev->keybit)) {
817 			joydev->keymap[i] = joydev->nkey;
818 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
819 			joydev->nkey++;
820 		}
821 
822 	for (i = 0; i < joydev->nabs; i++) {
823 		j = joydev->abspam[i];
824 		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {
825 			joydev->corr[i].type = JS_CORR_NONE;
826 			joydev->abs[i] = input_abs_get_val(dev, j);
827 			continue;
828 		}
829 		joydev->corr[i].type = JS_CORR_BROKEN;
830 		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
831 
832 		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
833 		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
834 		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);
835 
836 		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
837 			- 2 * input_abs_get_flat(dev, j);
838 		if (t) {
839 			joydev->corr[i].coef[2] = (1 << 29) / t;
840 			joydev->corr[i].coef[3] = (1 << 29) / t;
841 
842 			joydev->abs[i] =
843 				joydev_correct(input_abs_get_val(dev, j),
844 					       joydev->corr + i);
845 		}
846 	}
847 
848 	joydev->dev.devt = MKDEV(INPUT_MAJOR, minor);
849 	joydev->dev.class = &input_class;
850 	joydev->dev.parent = &dev->dev;
851 	joydev->dev.release = joydev_free;
852 	device_initialize(&joydev->dev);
853 
854 	error = input_register_handle(&joydev->handle);
855 	if (error)
856 		goto err_free_joydev;
857 
858 	cdev_init(&joydev->cdev, &joydev_fops);
859 	joydev->cdev.kobj.parent = &joydev->dev.kobj;
860 	error = cdev_add(&joydev->cdev, joydev->dev.devt, 1);
861 	if (error)
862 		goto err_unregister_handle;
863 
864 	error = device_add(&joydev->dev);
865 	if (error)
866 		goto err_cleanup_joydev;
867 
868 	return 0;
869 
870  err_cleanup_joydev:
871 	joydev_cleanup(joydev);
872  err_unregister_handle:
873 	input_unregister_handle(&joydev->handle);
874  err_free_joydev:
875 	put_device(&joydev->dev);
876  err_free_minor:
877 	input_free_minor(minor);
878 	return error;
879 }
880 
881 static void joydev_disconnect(struct input_handle *handle)
882 {
883 	struct joydev *joydev = handle->private;
884 
885 	device_del(&joydev->dev);
886 	joydev_cleanup(joydev);
887 	input_free_minor(MINOR(joydev->dev.devt));
888 	input_unregister_handle(handle);
889 	put_device(&joydev->dev);
890 }
891 
892 static const struct input_device_id joydev_ids[] = {
893 	{
894 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
895 				INPUT_DEVICE_ID_MATCH_ABSBIT,
896 		.evbit = { BIT_MASK(EV_ABS) },
897 		.absbit = { BIT_MASK(ABS_X) },
898 	},
899 	{
900 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
901 				INPUT_DEVICE_ID_MATCH_ABSBIT,
902 		.evbit = { BIT_MASK(EV_ABS) },
903 		.absbit = { BIT_MASK(ABS_WHEEL) },
904 	},
905 	{
906 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
907 				INPUT_DEVICE_ID_MATCH_ABSBIT,
908 		.evbit = { BIT_MASK(EV_ABS) },
909 		.absbit = { BIT_MASK(ABS_THROTTLE) },
910 	},
911 	{
912 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
913 				INPUT_DEVICE_ID_MATCH_KEYBIT,
914 		.evbit = { BIT_MASK(EV_KEY) },
915 		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
916 	},
917 	{
918 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
919 				INPUT_DEVICE_ID_MATCH_KEYBIT,
920 		.evbit = { BIT_MASK(EV_KEY) },
921 		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
922 	},
923 	{
924 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
925 				INPUT_DEVICE_ID_MATCH_KEYBIT,
926 		.evbit = { BIT_MASK(EV_KEY) },
927 		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
928 	},
929 	{ }	/* Terminating entry */
930 };
931 
932 MODULE_DEVICE_TABLE(input, joydev_ids);
933 
934 static struct input_handler joydev_handler = {
935 	.event		= joydev_event,
936 	.match		= joydev_match,
937 	.connect	= joydev_connect,
938 	.disconnect	= joydev_disconnect,
939 	.legacy_minors	= true,
940 	.minor		= JOYDEV_MINOR_BASE,
941 	.name		= "joydev",
942 	.id_table	= joydev_ids,
943 };
944 
945 static int __init joydev_init(void)
946 {
947 	return input_register_handler(&joydev_handler);
948 }
949 
950 static void __exit joydev_exit(void)
951 {
952 	input_unregister_handler(&joydev_handler);
953 }
954 
955 module_init(joydev_init);
956 module_exit(joydev_exit);
957