xref: /openbmc/linux/drivers/media/rc/lirc_dev.c (revision 174cd4b1)
1 /*
2  * LIRC base driver
3  *
4  * by Artur Lipowski <alipowski@interia.pl>
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/sched/signal.h>
23 #include <linux/errno.h>
24 #include <linux/ioctl.h>
25 #include <linux/fs.h>
26 #include <linux/poll.h>
27 #include <linux/completion.h>
28 #include <linux/mutex.h>
29 #include <linux/wait.h>
30 #include <linux/unistd.h>
31 #include <linux/kthread.h>
32 #include <linux/bitops.h>
33 #include <linux/device.h>
34 #include <linux/cdev.h>
35 
36 #include <media/rc-core.h>
37 #include <media/lirc.h>
38 #include <media/lirc_dev.h>
39 
40 static bool debug;
41 
42 #define IRCTL_DEV_NAME	"BaseRemoteCtl"
43 #define NOPLUG		-1
44 #define LOGHEAD		"lirc_dev (%s[%d]): "
45 
46 static dev_t lirc_base_dev;
47 
48 struct irctl {
49 	struct lirc_driver d;
50 	int attached;
51 	int open;
52 
53 	struct mutex irctl_lock;
54 	struct lirc_buffer *buf;
55 	unsigned int chunk_size;
56 
57 	struct cdev *cdev;
58 
59 	struct task_struct *task;
60 	long jiffies_to_wait;
61 };
62 
63 static DEFINE_MUTEX(lirc_dev_lock);
64 
65 static struct irctl *irctls[MAX_IRCTL_DEVICES];
66 
67 /* Only used for sysfs but defined to void otherwise */
68 static struct class *lirc_class;
69 
70 /*  helper function
71  *  initializes the irctl structure
72  */
73 static void lirc_irctl_init(struct irctl *ir)
74 {
75 	mutex_init(&ir->irctl_lock);
76 	ir->d.minor = NOPLUG;
77 }
78 
79 static void lirc_irctl_cleanup(struct irctl *ir)
80 {
81 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
82 
83 	if (ir->buf != ir->d.rbuf) {
84 		lirc_buffer_free(ir->buf);
85 		kfree(ir->buf);
86 	}
87 	ir->buf = NULL;
88 }
89 
90 /*  helper function
91  *  reads key codes from driver and puts them into buffer
92  *  returns 0 on success
93  */
94 static int lirc_add_to_buf(struct irctl *ir)
95 {
96 	int res;
97 	int got_data = -1;
98 
99 	if (!ir->d.add_to_buf)
100 		return 0;
101 
102 	/*
103 	 * service the device as long as it is returning
104 	 * data and we have space
105 	 */
106 	do {
107 		got_data++;
108 		res = ir->d.add_to_buf(ir->d.data, ir->buf);
109 	} while (!res);
110 
111 	if (res == -ENODEV)
112 		kthread_stop(ir->task);
113 
114 	return got_data ? 0 : res;
115 }
116 
117 /* main function of the polling thread
118  */
119 static int lirc_thread(void *irctl)
120 {
121 	struct irctl *ir = irctl;
122 
123 	do {
124 		if (ir->open) {
125 			if (ir->jiffies_to_wait) {
126 				set_current_state(TASK_INTERRUPTIBLE);
127 				schedule_timeout(ir->jiffies_to_wait);
128 			}
129 			if (kthread_should_stop())
130 				break;
131 			if (!lirc_add_to_buf(ir))
132 				wake_up_interruptible(&ir->buf->wait_poll);
133 		} else {
134 			set_current_state(TASK_INTERRUPTIBLE);
135 			schedule();
136 		}
137 	} while (!kthread_should_stop());
138 
139 	return 0;
140 }
141 
142 
143 static const struct file_operations lirc_dev_fops = {
144 	.owner		= THIS_MODULE,
145 	.read		= lirc_dev_fop_read,
146 	.write		= lirc_dev_fop_write,
147 	.poll		= lirc_dev_fop_poll,
148 	.unlocked_ioctl	= lirc_dev_fop_ioctl,
149 	.open		= lirc_dev_fop_open,
150 	.release	= lirc_dev_fop_close,
151 	.llseek		= noop_llseek,
152 };
153 
154 static int lirc_cdev_add(struct irctl *ir)
155 {
156 	struct lirc_driver *d = &ir->d;
157 	struct cdev *cdev;
158 	int retval;
159 
160 	cdev = cdev_alloc();
161 	if (!cdev)
162 		return -ENOMEM;
163 
164 	if (d->fops) {
165 		cdev->ops = d->fops;
166 		cdev->owner = d->owner;
167 	} else {
168 		cdev->ops = &lirc_dev_fops;
169 		cdev->owner = THIS_MODULE;
170 	}
171 	retval = kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
172 	if (retval)
173 		goto err_out;
174 
175 	retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
176 	if (retval)
177 		goto err_out;
178 
179 	ir->cdev = cdev;
180 
181 	return 0;
182 
183 err_out:
184 	cdev_del(cdev);
185 	return retval;
186 }
187 
188 static int lirc_allocate_buffer(struct irctl *ir)
189 {
190 	int err = 0;
191 	int bytes_in_key;
192 	unsigned int chunk_size;
193 	unsigned int buffer_size;
194 	struct lirc_driver *d = &ir->d;
195 
196 	mutex_lock(&lirc_dev_lock);
197 
198 	bytes_in_key = BITS_TO_LONGS(d->code_length) +
199 						(d->code_length % 8 ? 1 : 0);
200 	buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
201 	chunk_size  = d->chunk_size  ? d->chunk_size  : bytes_in_key;
202 
203 	if (d->rbuf) {
204 		ir->buf = d->rbuf;
205 	} else {
206 		ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
207 		if (!ir->buf) {
208 			err = -ENOMEM;
209 			goto out;
210 		}
211 
212 		err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
213 		if (err) {
214 			kfree(ir->buf);
215 			goto out;
216 		}
217 	}
218 	ir->chunk_size = ir->buf->chunk_size;
219 
220 out:
221 	mutex_unlock(&lirc_dev_lock);
222 
223 	return err;
224 }
225 
226 static int lirc_allocate_driver(struct lirc_driver *d)
227 {
228 	struct irctl *ir;
229 	int minor;
230 	int err;
231 
232 	if (!d) {
233 		pr_err("driver pointer must be not NULL!\n");
234 		return -EBADRQC;
235 	}
236 
237 	if (!d->dev) {
238 		pr_err("dev pointer not filled in!\n");
239 		return -EINVAL;
240 	}
241 
242 	if (d->minor >= MAX_IRCTL_DEVICES) {
243 		dev_err(d->dev, "minor must be between 0 and %d!\n",
244 						MAX_IRCTL_DEVICES - 1);
245 		return -EBADRQC;
246 	}
247 
248 	if (d->code_length < 1 || d->code_length > (BUFLEN * 8)) {
249 		dev_err(d->dev, "code length must be less than %d bits\n",
250 								BUFLEN * 8);
251 		return -EBADRQC;
252 	}
253 
254 	if (d->sample_rate) {
255 		if (2 > d->sample_rate || HZ < d->sample_rate) {
256 			dev_err(d->dev, "invalid %d sample rate\n",
257 							d->sample_rate);
258 			return -EBADRQC;
259 		}
260 		if (!d->add_to_buf) {
261 			dev_err(d->dev, "add_to_buf not set\n");
262 			return -EBADRQC;
263 		}
264 	} else if (!d->rbuf && !(d->fops && d->fops->read &&
265 				d->fops->poll && d->fops->unlocked_ioctl)) {
266 		dev_err(d->dev, "undefined read, poll, ioctl\n");
267 		return -EBADRQC;
268 	}
269 
270 	mutex_lock(&lirc_dev_lock);
271 
272 	minor = d->minor;
273 
274 	if (minor < 0) {
275 		/* find first free slot for driver */
276 		for (minor = 0; minor < MAX_IRCTL_DEVICES; minor++)
277 			if (!irctls[minor])
278 				break;
279 		if (minor == MAX_IRCTL_DEVICES) {
280 			dev_err(d->dev, "no free slots for drivers!\n");
281 			err = -ENOMEM;
282 			goto out_lock;
283 		}
284 	} else if (irctls[minor]) {
285 		dev_err(d->dev, "minor (%d) just registered!\n", minor);
286 		err = -EBUSY;
287 		goto out_lock;
288 	}
289 
290 	ir = kzalloc(sizeof(struct irctl), GFP_KERNEL);
291 	if (!ir) {
292 		err = -ENOMEM;
293 		goto out_lock;
294 	}
295 	lirc_irctl_init(ir);
296 	irctls[minor] = ir;
297 	d->minor = minor;
298 
299 	/* some safety check 8-) */
300 	d->name[sizeof(d->name)-1] = '\0';
301 
302 	if (d->features == 0)
303 		d->features = LIRC_CAN_REC_LIRCCODE;
304 
305 	ir->d = *d;
306 
307 	device_create(lirc_class, ir->d.dev,
308 		      MKDEV(MAJOR(lirc_base_dev), ir->d.minor), NULL,
309 		      "lirc%u", ir->d.minor);
310 
311 	if (d->sample_rate) {
312 		ir->jiffies_to_wait = HZ / d->sample_rate;
313 
314 		/* try to fire up polling thread */
315 		ir->task = kthread_run(lirc_thread, (void *)ir, "lirc_dev");
316 		if (IS_ERR(ir->task)) {
317 			dev_err(d->dev, "cannot run thread for minor = %d\n",
318 								d->minor);
319 			err = -ECHILD;
320 			goto out_sysfs;
321 		}
322 	} else {
323 		/* it means - wait for external event in task queue */
324 		ir->jiffies_to_wait = 0;
325 	}
326 
327 	err = lirc_cdev_add(ir);
328 	if (err)
329 		goto out_sysfs;
330 
331 	ir->attached = 1;
332 	mutex_unlock(&lirc_dev_lock);
333 
334 	dev_info(ir->d.dev, "lirc_dev: driver %s registered at minor = %d\n",
335 		 ir->d.name, ir->d.minor);
336 	return minor;
337 
338 out_sysfs:
339 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
340 out_lock:
341 	mutex_unlock(&lirc_dev_lock);
342 
343 	return err;
344 }
345 
346 int lirc_register_driver(struct lirc_driver *d)
347 {
348 	int minor, err = 0;
349 
350 	minor = lirc_allocate_driver(d);
351 	if (minor < 0)
352 		return minor;
353 
354 	if (LIRC_CAN_REC(d->features)) {
355 		err = lirc_allocate_buffer(irctls[minor]);
356 		if (err)
357 			lirc_unregister_driver(minor);
358 	}
359 
360 	return err ? err : minor;
361 }
362 EXPORT_SYMBOL(lirc_register_driver);
363 
364 int lirc_unregister_driver(int minor)
365 {
366 	struct irctl *ir;
367 	struct cdev *cdev;
368 
369 	if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
370 		pr_err("minor (%d) must be between 0 and %d!\n",
371 					minor, MAX_IRCTL_DEVICES - 1);
372 		return -EBADRQC;
373 	}
374 
375 	ir = irctls[minor];
376 	if (!ir) {
377 		pr_err("failed to get irctl\n");
378 		return -ENOENT;
379 	}
380 
381 	cdev = ir->cdev;
382 
383 	mutex_lock(&lirc_dev_lock);
384 
385 	if (ir->d.minor != minor) {
386 		dev_err(ir->d.dev, "lirc_dev: minor %d device not registered\n",
387 									minor);
388 		mutex_unlock(&lirc_dev_lock);
389 		return -ENOENT;
390 	}
391 
392 	/* end up polling thread */
393 	if (ir->task)
394 		kthread_stop(ir->task);
395 
396 	dev_dbg(ir->d.dev, "lirc_dev: driver %s unregistered from minor = %d\n",
397 		ir->d.name, ir->d.minor);
398 
399 	ir->attached = 0;
400 	if (ir->open) {
401 		dev_dbg(ir->d.dev, LOGHEAD "releasing opened driver\n",
402 			ir->d.name, ir->d.minor);
403 		wake_up_interruptible(&ir->buf->wait_poll);
404 		mutex_lock(&ir->irctl_lock);
405 
406 		if (ir->d.set_use_dec)
407 			ir->d.set_use_dec(ir->d.data);
408 
409 		module_put(cdev->owner);
410 		mutex_unlock(&ir->irctl_lock);
411 	} else {
412 		lirc_irctl_cleanup(ir);
413 		cdev_del(cdev);
414 		kfree(ir);
415 		irctls[minor] = NULL;
416 	}
417 
418 	mutex_unlock(&lirc_dev_lock);
419 
420 	return 0;
421 }
422 EXPORT_SYMBOL(lirc_unregister_driver);
423 
424 int lirc_dev_fop_open(struct inode *inode, struct file *file)
425 {
426 	struct irctl *ir;
427 	struct cdev *cdev;
428 	int retval = 0;
429 
430 	if (iminor(inode) >= MAX_IRCTL_DEVICES) {
431 		pr_err("open result for %d is -ENODEV\n", iminor(inode));
432 		return -ENODEV;
433 	}
434 
435 	if (mutex_lock_interruptible(&lirc_dev_lock))
436 		return -ERESTARTSYS;
437 
438 	ir = irctls[iminor(inode)];
439 	if (!ir) {
440 		retval = -ENODEV;
441 		goto error;
442 	}
443 
444 	dev_dbg(ir->d.dev, LOGHEAD "open called\n", ir->d.name, ir->d.minor);
445 
446 	if (ir->d.minor == NOPLUG) {
447 		retval = -ENODEV;
448 		goto error;
449 	}
450 
451 	if (ir->open) {
452 		retval = -EBUSY;
453 		goto error;
454 	}
455 
456 	if (ir->d.rdev) {
457 		retval = rc_open(ir->d.rdev);
458 		if (retval)
459 			goto error;
460 	}
461 
462 	cdev = ir->cdev;
463 	if (try_module_get(cdev->owner)) {
464 		ir->open++;
465 		if (ir->d.set_use_inc)
466 			retval = ir->d.set_use_inc(ir->d.data);
467 
468 		if (retval) {
469 			module_put(cdev->owner);
470 			ir->open--;
471 		} else if (ir->buf) {
472 			lirc_buffer_clear(ir->buf);
473 		}
474 		if (ir->task)
475 			wake_up_process(ir->task);
476 	}
477 
478 error:
479 	mutex_unlock(&lirc_dev_lock);
480 
481 	nonseekable_open(inode, file);
482 
483 	return retval;
484 }
485 EXPORT_SYMBOL(lirc_dev_fop_open);
486 
487 int lirc_dev_fop_close(struct inode *inode, struct file *file)
488 {
489 	struct irctl *ir = irctls[iminor(inode)];
490 	struct cdev *cdev;
491 	int ret;
492 
493 	if (!ir) {
494 		pr_err("called with invalid irctl\n");
495 		return -EINVAL;
496 	}
497 
498 	cdev = ir->cdev;
499 
500 	ret = mutex_lock_killable(&lirc_dev_lock);
501 	WARN_ON(ret);
502 
503 	rc_close(ir->d.rdev);
504 
505 	ir->open--;
506 	if (ir->attached) {
507 		if (ir->d.set_use_dec)
508 			ir->d.set_use_dec(ir->d.data);
509 		module_put(cdev->owner);
510 	} else {
511 		lirc_irctl_cleanup(ir);
512 		cdev_del(cdev);
513 		irctls[ir->d.minor] = NULL;
514 		kfree(ir);
515 	}
516 
517 	if (!ret)
518 		mutex_unlock(&lirc_dev_lock);
519 
520 	return 0;
521 }
522 EXPORT_SYMBOL(lirc_dev_fop_close);
523 
524 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
525 {
526 	struct irctl *ir = irctls[iminor(file_inode(file))];
527 	unsigned int ret;
528 
529 	if (!ir) {
530 		pr_err("called with invalid irctl\n");
531 		return POLLERR;
532 	}
533 
534 	if (!ir->attached)
535 		return POLLERR;
536 
537 	if (ir->buf) {
538 		poll_wait(file, &ir->buf->wait_poll, wait);
539 
540 		if (lirc_buffer_empty(ir->buf))
541 			ret = 0;
542 		else
543 			ret = POLLIN | POLLRDNORM;
544 	} else
545 		ret = POLLERR;
546 
547 	dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
548 		ir->d.name, ir->d.minor, ret);
549 
550 	return ret;
551 }
552 EXPORT_SYMBOL(lirc_dev_fop_poll);
553 
554 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
555 {
556 	__u32 mode;
557 	int result = 0;
558 	struct irctl *ir = irctls[iminor(file_inode(file))];
559 
560 	if (!ir) {
561 		pr_err("no irctl found!\n");
562 		return -ENODEV;
563 	}
564 
565 	dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
566 		ir->d.name, ir->d.minor, cmd);
567 
568 	if (ir->d.minor == NOPLUG || !ir->attached) {
569 		dev_err(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
570 			ir->d.name, ir->d.minor);
571 		return -ENODEV;
572 	}
573 
574 	mutex_lock(&ir->irctl_lock);
575 
576 	switch (cmd) {
577 	case LIRC_GET_FEATURES:
578 		result = put_user(ir->d.features, (__u32 __user *)arg);
579 		break;
580 	case LIRC_GET_REC_MODE:
581 		if (!LIRC_CAN_REC(ir->d.features)) {
582 			result = -ENOTTY;
583 			break;
584 		}
585 
586 		result = put_user(LIRC_REC2MODE
587 				  (ir->d.features & LIRC_CAN_REC_MASK),
588 				  (__u32 __user *)arg);
589 		break;
590 	case LIRC_SET_REC_MODE:
591 		if (!LIRC_CAN_REC(ir->d.features)) {
592 			result = -ENOTTY;
593 			break;
594 		}
595 
596 		result = get_user(mode, (__u32 __user *)arg);
597 		if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
598 			result = -EINVAL;
599 		/*
600 		 * FIXME: We should actually set the mode somehow but
601 		 * for now, lirc_serial doesn't support mode changing either
602 		 */
603 		break;
604 	case LIRC_GET_LENGTH:
605 		result = put_user(ir->d.code_length, (__u32 __user *)arg);
606 		break;
607 	case LIRC_GET_MIN_TIMEOUT:
608 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
609 		    ir->d.min_timeout == 0) {
610 			result = -ENOTTY;
611 			break;
612 		}
613 
614 		result = put_user(ir->d.min_timeout, (__u32 __user *)arg);
615 		break;
616 	case LIRC_GET_MAX_TIMEOUT:
617 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
618 		    ir->d.max_timeout == 0) {
619 			result = -ENOTTY;
620 			break;
621 		}
622 
623 		result = put_user(ir->d.max_timeout, (__u32 __user *)arg);
624 		break;
625 	default:
626 		result = -EINVAL;
627 	}
628 
629 	mutex_unlock(&ir->irctl_lock);
630 
631 	return result;
632 }
633 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
634 
635 ssize_t lirc_dev_fop_read(struct file *file,
636 			  char __user *buffer,
637 			  size_t length,
638 			  loff_t *ppos)
639 {
640 	struct irctl *ir = irctls[iminor(file_inode(file))];
641 	unsigned char *buf;
642 	int ret = 0, written = 0;
643 	DECLARE_WAITQUEUE(wait, current);
644 
645 	if (!ir) {
646 		pr_err("called with invalid irctl\n");
647 		return -ENODEV;
648 	}
649 
650 	if (!LIRC_CAN_REC(ir->d.features))
651 		return -EINVAL;
652 
653 	dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
654 
655 	buf = kzalloc(ir->chunk_size, GFP_KERNEL);
656 	if (!buf)
657 		return -ENOMEM;
658 
659 	if (mutex_lock_interruptible(&ir->irctl_lock)) {
660 		ret = -ERESTARTSYS;
661 		goto out_unlocked;
662 	}
663 	if (!ir->attached) {
664 		ret = -ENODEV;
665 		goto out_locked;
666 	}
667 
668 	if (length % ir->chunk_size) {
669 		ret = -EINVAL;
670 		goto out_locked;
671 	}
672 
673 	/*
674 	 * we add ourselves to the task queue before buffer check
675 	 * to avoid losing scan code (in case when queue is awaken somewhere
676 	 * between while condition checking and scheduling)
677 	 */
678 	add_wait_queue(&ir->buf->wait_poll, &wait);
679 
680 	/*
681 	 * while we didn't provide 'length' bytes, device is opened in blocking
682 	 * mode and 'copy_to_user' is happy, wait for data.
683 	 */
684 	while (written < length && ret == 0) {
685 		if (lirc_buffer_empty(ir->buf)) {
686 			/* According to the read(2) man page, 'written' can be
687 			 * returned as less than 'length', instead of blocking
688 			 * again, returning -EWOULDBLOCK, or returning
689 			 * -ERESTARTSYS
690 			 */
691 			if (written)
692 				break;
693 			if (file->f_flags & O_NONBLOCK) {
694 				ret = -EWOULDBLOCK;
695 				break;
696 			}
697 			if (signal_pending(current)) {
698 				ret = -ERESTARTSYS;
699 				break;
700 			}
701 
702 			mutex_unlock(&ir->irctl_lock);
703 			set_current_state(TASK_INTERRUPTIBLE);
704 			schedule();
705 			set_current_state(TASK_RUNNING);
706 
707 			if (mutex_lock_interruptible(&ir->irctl_lock)) {
708 				ret = -ERESTARTSYS;
709 				remove_wait_queue(&ir->buf->wait_poll, &wait);
710 				goto out_unlocked;
711 			}
712 
713 			if (!ir->attached) {
714 				ret = -ENODEV;
715 				goto out_locked;
716 			}
717 		} else {
718 			lirc_buffer_read(ir->buf, buf);
719 			ret = copy_to_user((void __user *)buffer+written, buf,
720 					   ir->buf->chunk_size);
721 			if (!ret)
722 				written += ir->buf->chunk_size;
723 			else
724 				ret = -EFAULT;
725 		}
726 	}
727 
728 	remove_wait_queue(&ir->buf->wait_poll, &wait);
729 
730 out_locked:
731 	mutex_unlock(&ir->irctl_lock);
732 
733 out_unlocked:
734 	kfree(buf);
735 
736 	return ret ? ret : written;
737 }
738 EXPORT_SYMBOL(lirc_dev_fop_read);
739 
740 void *lirc_get_pdata(struct file *file)
741 {
742 	return irctls[iminor(file_inode(file))]->d.data;
743 }
744 EXPORT_SYMBOL(lirc_get_pdata);
745 
746 
747 ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
748 			   size_t length, loff_t *ppos)
749 {
750 	struct irctl *ir = irctls[iminor(file_inode(file))];
751 
752 	if (!ir) {
753 		pr_err("called with invalid irctl\n");
754 		return -ENODEV;
755 	}
756 
757 	if (!ir->attached)
758 		return -ENODEV;
759 
760 	return -EINVAL;
761 }
762 EXPORT_SYMBOL(lirc_dev_fop_write);
763 
764 
765 static int __init lirc_dev_init(void)
766 {
767 	int retval;
768 
769 	lirc_class = class_create(THIS_MODULE, "lirc");
770 	if (IS_ERR(lirc_class)) {
771 		pr_err("class_create failed\n");
772 		return PTR_ERR(lirc_class);
773 	}
774 
775 	retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
776 				     IRCTL_DEV_NAME);
777 	if (retval) {
778 		class_destroy(lirc_class);
779 		pr_err("alloc_chrdev_region failed\n");
780 		return retval;
781 	}
782 
783 
784 	pr_info("IR Remote Control driver registered, major %d\n",
785 						MAJOR(lirc_base_dev));
786 
787 	return 0;
788 }
789 
790 
791 
792 static void __exit lirc_dev_exit(void)
793 {
794 	class_destroy(lirc_class);
795 	unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
796 	pr_info("module unloaded\n");
797 }
798 
799 module_init(lirc_dev_init);
800 module_exit(lirc_dev_exit);
801 
802 MODULE_DESCRIPTION("LIRC base driver module");
803 MODULE_AUTHOR("Artur Lipowski");
804 MODULE_LICENSE("GPL");
805 
806 module_param(debug, bool, S_IRUGO | S_IWUSR);
807 MODULE_PARM_DESC(debug, "Enable debugging messages");
808