xref: /openbmc/linux/drivers/media/rc/lirc_dev.c (revision 4800cd83)
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  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  *
20  */
21 
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/errno.h>
26 #include <linux/ioctl.h>
27 #include <linux/fs.h>
28 #include <linux/poll.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
31 #include <linux/wait.h>
32 #include <linux/unistd.h>
33 #include <linux/kthread.h>
34 #include <linux/bitops.h>
35 #include <linux/device.h>
36 #include <linux/cdev.h>
37 
38 #include <media/lirc.h>
39 #include <media/lirc_dev.h>
40 
41 static int debug;
42 
43 #define IRCTL_DEV_NAME	"BaseRemoteCtl"
44 #define NOPLUG		-1
45 #define LOGHEAD		"lirc_dev (%s[%d]): "
46 
47 static dev_t lirc_base_dev;
48 
49 struct irctl {
50 	struct lirc_driver d;
51 	int attached;
52 	int open;
53 
54 	struct mutex irctl_lock;
55 	struct lirc_buffer *buf;
56 	unsigned int chunk_size;
57 
58 	struct task_struct *task;
59 	long jiffies_to_wait;
60 };
61 
62 static DEFINE_MUTEX(lirc_dev_lock);
63 
64 static struct irctl *irctls[MAX_IRCTL_DEVICES];
65 static struct cdev cdevs[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 	dev_dbg(ir->d.dev, LOGHEAD "cleaning up\n", ir->d.name, ir->d.minor);
82 
83 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
84 
85 	if (ir->buf != ir->d.rbuf) {
86 		lirc_buffer_free(ir->buf);
87 		kfree(ir->buf);
88 	}
89 	ir->buf = NULL;
90 }
91 
92 /*  helper function
93  *  reads key codes from driver and puts them into buffer
94  *  returns 0 on success
95  */
96 static int lirc_add_to_buf(struct irctl *ir)
97 {
98 	if (ir->d.add_to_buf) {
99 		int res = -ENODATA;
100 		int got_data = 0;
101 
102 		/*
103 		 * service the device as long as it is returning
104 		 * data and we have space
105 		 */
106 get_data:
107 		res = ir->d.add_to_buf(ir->d.data, ir->buf);
108 		if (res == 0) {
109 			got_data++;
110 			goto get_data;
111 		}
112 
113 		if (res == -ENODEV)
114 			kthread_stop(ir->task);
115 
116 		return got_data ? 0 : res;
117 	}
118 
119 	return 0;
120 }
121 
122 /* main function of the polling thread
123  */
124 static int lirc_thread(void *irctl)
125 {
126 	struct irctl *ir = irctl;
127 
128 	dev_dbg(ir->d.dev, LOGHEAD "poll thread started\n",
129 		ir->d.name, ir->d.minor);
130 
131 	do {
132 		if (ir->open) {
133 			if (ir->jiffies_to_wait) {
134 				set_current_state(TASK_INTERRUPTIBLE);
135 				schedule_timeout(ir->jiffies_to_wait);
136 			}
137 			if (kthread_should_stop())
138 				break;
139 			if (!lirc_add_to_buf(ir))
140 				wake_up_interruptible(&ir->buf->wait_poll);
141 		} else {
142 			set_current_state(TASK_INTERRUPTIBLE);
143 			schedule();
144 		}
145 	} while (!kthread_should_stop());
146 
147 	dev_dbg(ir->d.dev, LOGHEAD "poll thread ended\n",
148 		ir->d.name, ir->d.minor);
149 
150 	return 0;
151 }
152 
153 
154 static struct file_operations lirc_dev_fops = {
155 	.owner		= THIS_MODULE,
156 	.read		= lirc_dev_fop_read,
157 	.write		= lirc_dev_fop_write,
158 	.poll		= lirc_dev_fop_poll,
159 	.unlocked_ioctl	= lirc_dev_fop_ioctl,
160 #ifdef CONFIG_COMPAT
161 	.compat_ioctl	= lirc_dev_fop_ioctl,
162 #endif
163 	.open		= lirc_dev_fop_open,
164 	.release	= lirc_dev_fop_close,
165 	.llseek		= noop_llseek,
166 };
167 
168 static int lirc_cdev_add(struct irctl *ir)
169 {
170 	int retval;
171 	struct lirc_driver *d = &ir->d;
172 	struct cdev *cdev = &cdevs[d->minor];
173 
174 	if (d->fops) {
175 		cdev_init(cdev, d->fops);
176 		cdev->owner = d->owner;
177 	} else {
178 		cdev_init(cdev, &lirc_dev_fops);
179 		cdev->owner = THIS_MODULE;
180 	}
181 	retval = kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
182 	if (retval)
183 		return retval;
184 
185 	retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
186 	if (retval)
187 		kobject_put(&cdev->kobj);
188 
189 	return retval;
190 }
191 
192 int lirc_register_driver(struct lirc_driver *d)
193 {
194 	struct irctl *ir;
195 	int minor;
196 	int bytes_in_key;
197 	unsigned int chunk_size;
198 	unsigned int buffer_size;
199 	int err;
200 
201 	if (!d) {
202 		printk(KERN_ERR "lirc_dev: lirc_register_driver: "
203 		       "driver pointer must be not NULL!\n");
204 		err = -EBADRQC;
205 		goto out;
206 	}
207 
208 	if (!d->dev) {
209 		printk(KERN_ERR "%s: dev pointer not filled in!\n", __func__);
210 		err = -EINVAL;
211 		goto out;
212 	}
213 
214 	if (MAX_IRCTL_DEVICES <= d->minor) {
215 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
216 			"\"minor\" must be between 0 and %d (%d)!\n",
217 			MAX_IRCTL_DEVICES-1, d->minor);
218 		err = -EBADRQC;
219 		goto out;
220 	}
221 
222 	if (1 > d->code_length || (BUFLEN * 8) < d->code_length) {
223 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
224 			"code length in bits for minor (%d) "
225 			"must be less than %d!\n",
226 			d->minor, BUFLEN * 8);
227 		err = -EBADRQC;
228 		goto out;
229 	}
230 
231 	dev_dbg(d->dev, "lirc_dev: lirc_register_driver: sample_rate: %d\n",
232 		d->sample_rate);
233 	if (d->sample_rate) {
234 		if (2 > d->sample_rate || HZ < d->sample_rate) {
235 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
236 				"sample_rate must be between 2 and %d!\n", HZ);
237 			err = -EBADRQC;
238 			goto out;
239 		}
240 		if (!d->add_to_buf) {
241 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
242 				"add_to_buf cannot be NULL when "
243 				"sample_rate is set\n");
244 			err = -EBADRQC;
245 			goto out;
246 		}
247 	} else if (!(d->fops && d->fops->read) && !d->rbuf) {
248 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
249 			"fops->read and rbuf cannot all be NULL!\n");
250 		err = -EBADRQC;
251 		goto out;
252 	} else if (!d->rbuf) {
253 		if (!(d->fops && d->fops->read && d->fops->poll &&
254 		      d->fops->unlocked_ioctl)) {
255 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
256 				"neither read, poll nor unlocked_ioctl can be NULL!\n");
257 			err = -EBADRQC;
258 			goto out;
259 		}
260 	}
261 
262 	mutex_lock(&lirc_dev_lock);
263 
264 	minor = d->minor;
265 
266 	if (minor < 0) {
267 		/* find first free slot for driver */
268 		for (minor = 0; minor < MAX_IRCTL_DEVICES; minor++)
269 			if (!irctls[minor])
270 				break;
271 		if (MAX_IRCTL_DEVICES == minor) {
272 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
273 				"no free slots for drivers!\n");
274 			err = -ENOMEM;
275 			goto out_lock;
276 		}
277 	} else if (irctls[minor]) {
278 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
279 			"minor (%d) just registered!\n", minor);
280 		err = -EBUSY;
281 		goto out_lock;
282 	}
283 
284 	ir = kzalloc(sizeof(struct irctl), GFP_KERNEL);
285 	if (!ir) {
286 		err = -ENOMEM;
287 		goto out_lock;
288 	}
289 	lirc_irctl_init(ir);
290 	irctls[minor] = ir;
291 	d->minor = minor;
292 
293 	if (d->sample_rate) {
294 		ir->jiffies_to_wait = HZ / d->sample_rate;
295 	} else {
296 		/* it means - wait for external event in task queue */
297 		ir->jiffies_to_wait = 0;
298 	}
299 
300 	/* some safety check 8-) */
301 	d->name[sizeof(d->name)-1] = '\0';
302 
303 	bytes_in_key = BITS_TO_LONGS(d->code_length) +
304 			(d->code_length % 8 ? 1 : 0);
305 	buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
306 	chunk_size  = d->chunk_size  ? d->chunk_size  : bytes_in_key;
307 
308 	if (d->rbuf) {
309 		ir->buf = d->rbuf;
310 	} else {
311 		ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
312 		if (!ir->buf) {
313 			err = -ENOMEM;
314 			goto out_lock;
315 		}
316 		err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
317 		if (err) {
318 			kfree(ir->buf);
319 			goto out_lock;
320 		}
321 	}
322 	ir->chunk_size = ir->buf->chunk_size;
323 
324 	if (d->features == 0)
325 		d->features = LIRC_CAN_REC_LIRCCODE;
326 
327 	ir->d = *d;
328 
329 	device_create(lirc_class, ir->d.dev,
330 		      MKDEV(MAJOR(lirc_base_dev), ir->d.minor), NULL,
331 		      "lirc%u", ir->d.minor);
332 
333 	if (d->sample_rate) {
334 		/* try to fire up polling thread */
335 		ir->task = kthread_run(lirc_thread, (void *)ir, "lirc_dev");
336 		if (IS_ERR(ir->task)) {
337 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
338 				"cannot run poll thread for minor = %d\n",
339 				d->minor);
340 			err = -ECHILD;
341 			goto out_sysfs;
342 		}
343 	}
344 
345 	err = lirc_cdev_add(ir);
346 	if (err)
347 		goto out_sysfs;
348 
349 	ir->attached = 1;
350 	mutex_unlock(&lirc_dev_lock);
351 
352 	dev_info(ir->d.dev, "lirc_dev: driver %s registered at minor = %d\n",
353 		 ir->d.name, ir->d.minor);
354 	return minor;
355 
356 out_sysfs:
357 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
358 out_lock:
359 	mutex_unlock(&lirc_dev_lock);
360 out:
361 	return err;
362 }
363 EXPORT_SYMBOL(lirc_register_driver);
364 
365 int lirc_unregister_driver(int minor)
366 {
367 	struct irctl *ir;
368 	struct cdev *cdev;
369 
370 	if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
371 		printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
372 		       "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES-1);
373 		return -EBADRQC;
374 	}
375 
376 	ir = irctls[minor];
377 	if (!ir) {
378 		printk(KERN_ERR "lirc_dev: %s: failed to get irctl struct "
379 		       "for minor %d!\n", __func__, minor);
380 		return -ENOENT;
381 	}
382 
383 	cdev = &cdevs[minor];
384 
385 	mutex_lock(&lirc_dev_lock);
386 
387 	if (ir->d.minor != minor) {
388 		printk(KERN_ERR "lirc_dev: %s: minor (%d) device not "
389 		       "registered!\n", __func__, minor);
390 		mutex_unlock(&lirc_dev_lock);
391 		return -ENOENT;
392 	}
393 
394 	/* end up polling thread */
395 	if (ir->task)
396 		kthread_stop(ir->task);
397 
398 	dev_dbg(ir->d.dev, "lirc_dev: driver %s unregistered from minor = %d\n",
399 		ir->d.name, ir->d.minor);
400 
401 	ir->attached = 0;
402 	if (ir->open) {
403 		dev_dbg(ir->d.dev, LOGHEAD "releasing opened driver\n",
404 			ir->d.name, ir->d.minor);
405 		wake_up_interruptible(&ir->buf->wait_poll);
406 		mutex_lock(&ir->irctl_lock);
407 		ir->d.set_use_dec(ir->d.data);
408 		module_put(cdev->owner);
409 		mutex_unlock(&ir->irctl_lock);
410 	} else {
411 		lirc_irctl_cleanup(ir);
412 		cdev_del(cdev);
413 		kfree(ir);
414 		irctls[minor] = NULL;
415 	}
416 
417 	mutex_unlock(&lirc_dev_lock);
418 
419 	return 0;
420 }
421 EXPORT_SYMBOL(lirc_unregister_driver);
422 
423 int lirc_dev_fop_open(struct inode *inode, struct file *file)
424 {
425 	struct irctl *ir;
426 	struct cdev *cdev;
427 	int retval = 0;
428 
429 	if (iminor(inode) >= MAX_IRCTL_DEVICES) {
430 		printk(KERN_WARNING "lirc_dev [%d]: open result = -ENODEV\n",
431 		       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 	cdev = &cdevs[iminor(inode)];
457 	if (try_module_get(cdev->owner)) {
458 		ir->open++;
459 		retval = ir->d.set_use_inc(ir->d.data);
460 
461 		if (retval) {
462 			module_put(cdev->owner);
463 			ir->open--;
464 		} else {
465 			lirc_buffer_clear(ir->buf);
466 		}
467 		if (ir->task)
468 			wake_up_process(ir->task);
469 	}
470 
471 error:
472 	if (ir)
473 		dev_dbg(ir->d.dev, LOGHEAD "open result = %d\n",
474 			ir->d.name, ir->d.minor, retval);
475 
476 	mutex_unlock(&lirc_dev_lock);
477 
478 	nonseekable_open(inode, file);
479 
480 	return retval;
481 }
482 EXPORT_SYMBOL(lirc_dev_fop_open);
483 
484 int lirc_dev_fop_close(struct inode *inode, struct file *file)
485 {
486 	struct irctl *ir = irctls[iminor(inode)];
487 	struct cdev *cdev = &cdevs[iminor(inode)];
488 
489 	if (!ir) {
490 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
491 		return -EINVAL;
492 	}
493 
494 	dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
495 
496 	WARN_ON(mutex_lock_killable(&lirc_dev_lock));
497 
498 	ir->open--;
499 	if (ir->attached) {
500 		ir->d.set_use_dec(ir->d.data);
501 		module_put(cdev->owner);
502 	} else {
503 		lirc_irctl_cleanup(ir);
504 		cdev_del(cdev);
505 		irctls[ir->d.minor] = NULL;
506 		kfree(ir);
507 	}
508 
509 	mutex_unlock(&lirc_dev_lock);
510 
511 	return 0;
512 }
513 EXPORT_SYMBOL(lirc_dev_fop_close);
514 
515 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
516 {
517 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
518 	unsigned int ret;
519 
520 	if (!ir) {
521 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
522 		return POLLERR;
523 	}
524 
525 	dev_dbg(ir->d.dev, LOGHEAD "poll called\n", ir->d.name, ir->d.minor);
526 
527 	if (!ir->attached)
528 		return POLLERR;
529 
530 	poll_wait(file, &ir->buf->wait_poll, wait);
531 
532 	if (ir->buf)
533 		if (lirc_buffer_empty(ir->buf))
534 			ret = 0;
535 		else
536 			ret = POLLIN | POLLRDNORM;
537 	else
538 		ret = POLLERR;
539 
540 	dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
541 		ir->d.name, ir->d.minor, ret);
542 
543 	return ret;
544 }
545 EXPORT_SYMBOL(lirc_dev_fop_poll);
546 
547 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
548 {
549 	__u32 mode;
550 	int result = 0;
551 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
552 
553 	if (!ir) {
554 		printk(KERN_ERR "lirc_dev: %s: no irctl found!\n", __func__);
555 		return -ENODEV;
556 	}
557 
558 	dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
559 		ir->d.name, ir->d.minor, cmd);
560 
561 	if (ir->d.minor == NOPLUG || !ir->attached) {
562 		dev_dbg(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
563 			ir->d.name, ir->d.minor);
564 		return -ENODEV;
565 	}
566 
567 	mutex_lock(&ir->irctl_lock);
568 
569 	switch (cmd) {
570 	case LIRC_GET_FEATURES:
571 		result = put_user(ir->d.features, (__u32 *)arg);
572 		break;
573 	case LIRC_GET_REC_MODE:
574 		if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
575 			result = -ENOSYS;
576 			break;
577 		}
578 
579 		result = put_user(LIRC_REC2MODE
580 				  (ir->d.features & LIRC_CAN_REC_MASK),
581 				  (__u32 *)arg);
582 		break;
583 	case LIRC_SET_REC_MODE:
584 		if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
585 			result = -ENOSYS;
586 			break;
587 		}
588 
589 		result = get_user(mode, (__u32 *)arg);
590 		if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
591 			result = -EINVAL;
592 		/*
593 		 * FIXME: We should actually set the mode somehow but
594 		 * for now, lirc_serial doesn't support mode changing either
595 		 */
596 		break;
597 	case LIRC_GET_LENGTH:
598 		result = put_user(ir->d.code_length, (__u32 *)arg);
599 		break;
600 	case LIRC_GET_MIN_TIMEOUT:
601 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
602 		    ir->d.min_timeout == 0) {
603 			result = -ENOSYS;
604 			break;
605 		}
606 
607 		result = put_user(ir->d.min_timeout, (__u32 *)arg);
608 		break;
609 	case LIRC_GET_MAX_TIMEOUT:
610 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
611 		    ir->d.max_timeout == 0) {
612 			result = -ENOSYS;
613 			break;
614 		}
615 
616 		result = put_user(ir->d.max_timeout, (__u32 *)arg);
617 		break;
618 	default:
619 		result = -EINVAL;
620 	}
621 
622 	dev_dbg(ir->d.dev, LOGHEAD "ioctl result = %d\n",
623 		ir->d.name, ir->d.minor, result);
624 
625 	mutex_unlock(&ir->irctl_lock);
626 
627 	return result;
628 }
629 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
630 
631 ssize_t lirc_dev_fop_read(struct file *file,
632 			  char __user *buffer,
633 			  size_t length,
634 			  loff_t *ppos)
635 {
636 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
637 	unsigned char *buf;
638 	int ret = 0, written = 0;
639 	DECLARE_WAITQUEUE(wait, current);
640 
641 	if (!ir) {
642 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
643 		return -ENODEV;
644 	}
645 
646 	dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
647 
648 	buf = kzalloc(ir->chunk_size, GFP_KERNEL);
649 	if (!buf)
650 		return -ENOMEM;
651 
652 	if (mutex_lock_interruptible(&ir->irctl_lock)) {
653 		ret = -ERESTARTSYS;
654 		goto out_unlocked;
655 	}
656 	if (!ir->attached) {
657 		ret = -ENODEV;
658 		goto out_locked;
659 	}
660 
661 	if (length % ir->chunk_size) {
662 		ret = -EINVAL;
663 		goto out_locked;
664 	}
665 
666 	/*
667 	 * we add ourselves to the task queue before buffer check
668 	 * to avoid losing scan code (in case when queue is awaken somewhere
669 	 * between while condition checking and scheduling)
670 	 */
671 	add_wait_queue(&ir->buf->wait_poll, &wait);
672 	set_current_state(TASK_INTERRUPTIBLE);
673 
674 	/*
675 	 * while we didn't provide 'length' bytes, device is opened in blocking
676 	 * mode and 'copy_to_user' is happy, wait for data.
677 	 */
678 	while (written < length && ret == 0) {
679 		if (lirc_buffer_empty(ir->buf)) {
680 			/* According to the read(2) man page, 'written' can be
681 			 * returned as less than 'length', instead of blocking
682 			 * again, returning -EWOULDBLOCK, or returning
683 			 * -ERESTARTSYS */
684 			if (written)
685 				break;
686 			if (file->f_flags & O_NONBLOCK) {
687 				ret = -EWOULDBLOCK;
688 				break;
689 			}
690 			if (signal_pending(current)) {
691 				ret = -ERESTARTSYS;
692 				break;
693 			}
694 
695 			mutex_unlock(&ir->irctl_lock);
696 			schedule();
697 			set_current_state(TASK_INTERRUPTIBLE);
698 
699 			if (mutex_lock_interruptible(&ir->irctl_lock)) {
700 				ret = -ERESTARTSYS;
701 				remove_wait_queue(&ir->buf->wait_poll, &wait);
702 				set_current_state(TASK_RUNNING);
703 				goto out_unlocked;
704 			}
705 
706 			if (!ir->attached) {
707 				ret = -ENODEV;
708 				break;
709 			}
710 		} else {
711 			lirc_buffer_read(ir->buf, buf);
712 			ret = copy_to_user((void *)buffer+written, buf,
713 					   ir->buf->chunk_size);
714 			if (!ret)
715 				written += ir->buf->chunk_size;
716 			else
717 				ret = -EFAULT;
718 		}
719 	}
720 
721 	remove_wait_queue(&ir->buf->wait_poll, &wait);
722 	set_current_state(TASK_RUNNING);
723 
724 out_locked:
725 	mutex_unlock(&ir->irctl_lock);
726 
727 out_unlocked:
728 	kfree(buf);
729 	dev_dbg(ir->d.dev, LOGHEAD "read result = %s (%d)\n",
730 		ir->d.name, ir->d.minor, ret ? "<fail>" : "<ok>", ret);
731 
732 	return ret ? ret : written;
733 }
734 EXPORT_SYMBOL(lirc_dev_fop_read);
735 
736 void *lirc_get_pdata(struct file *file)
737 {
738 	void *data = NULL;
739 
740 	if (file && file->f_dentry && file->f_dentry->d_inode &&
741 	    file->f_dentry->d_inode->i_rdev) {
742 		struct irctl *ir;
743 		ir = irctls[iminor(file->f_dentry->d_inode)];
744 		data = ir->d.data;
745 	}
746 
747 	return data;
748 }
749 EXPORT_SYMBOL(lirc_get_pdata);
750 
751 
752 ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
753 			   size_t length, loff_t *ppos)
754 {
755 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
756 
757 	if (!ir) {
758 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
759 		return -ENODEV;
760 	}
761 
762 	dev_dbg(ir->d.dev, LOGHEAD "write called\n", ir->d.name, ir->d.minor);
763 
764 	if (!ir->attached)
765 		return -ENODEV;
766 
767 	return -EINVAL;
768 }
769 EXPORT_SYMBOL(lirc_dev_fop_write);
770 
771 
772 static int __init lirc_dev_init(void)
773 {
774 	int retval;
775 
776 	lirc_class = class_create(THIS_MODULE, "lirc");
777 	if (IS_ERR(lirc_class)) {
778 		retval = PTR_ERR(lirc_class);
779 		printk(KERN_ERR "lirc_dev: class_create failed\n");
780 		goto error;
781 	}
782 
783 	retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
784 				     IRCTL_DEV_NAME);
785 	if (retval) {
786 		class_destroy(lirc_class);
787 		printk(KERN_ERR "lirc_dev: alloc_chrdev_region failed\n");
788 		goto error;
789 	}
790 
791 
792 	printk(KERN_INFO "lirc_dev: IR Remote Control driver registered, "
793 	       "major %d \n", MAJOR(lirc_base_dev));
794 
795 error:
796 	return retval;
797 }
798 
799 
800 
801 static void __exit lirc_dev_exit(void)
802 {
803 	class_destroy(lirc_class);
804 	unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
805 	printk(KERN_INFO "lirc_dev: module unloaded\n");
806 }
807 
808 module_init(lirc_dev_init);
809 module_exit(lirc_dev_exit);
810 
811 MODULE_DESCRIPTION("LIRC base driver module");
812 MODULE_AUTHOR("Artur Lipowski");
813 MODULE_LICENSE("GPL");
814 
815 module_param(debug, bool, S_IRUGO | S_IWUSR);
816 MODULE_PARM_DESC(debug, "Enable debugging messages");
817