xref: /openbmc/linux/drivers/media/radio/radio-mr800.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  * A driver for the AverMedia MR 800 USB FM radio. This device plugs
3  * into both the USB and an analog audio input, so this thing
4  * only deals with initialization and frequency setting, the
5  * audio data has to be handled by a sound driver.
6  *
7  * Copyright (c) 2008 Alexey Klimov <klimov.linux@gmail.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22  */
23 
24 /*
25  * Big thanks to authors and contributors of dsbr100.c and radio-si470x.c
26  *
27  * When work was looked pretty good, i discover this:
28  * http://av-usbradio.sourceforge.net/index.php
29  * http://sourceforge.net/projects/av-usbradio/
30  * Latest release of theirs project was in 2005.
31  * Probably, this driver could be improved trough using their
32  * achievements (specifications given).
33  * Also, Faidon Liambotis <paravoid@debian.org> wrote nice driver for this radio
34  * in 2007. He allowed to use his driver to improve current mr800 radio driver.
35  * http://kerneltrap.org/mailarchive/linux-usb-devel/2007/10/11/342492
36  *
37  * Version 0.01:	First working version.
38  * 			It's required to blacklist AverMedia USB Radio
39  * 			in usbhid/hid-quirks.c
40  * Version 0.10:	A lot of cleanups and fixes: unpluging the device,
41  * 			few mutex locks were added, codinstyle issues, etc.
42  * 			Added stereo support. Thanks to
43  * 			Douglas Schilling Landgraf <dougsland@gmail.com> and
44  * 			David Ellingsworth <david@identd.dyndns.org>
45  * 			for discussion, help and support.
46  *
47  * Many things to do:
48  * 	- Correct power managment of device (suspend & resume)
49  * 	- Add code for scanning and smooth tuning
50  * 	- Add code for sensitivity value
51  * 	- Correct mistakes
52  * 	- In Japan another FREQ_MIN and FREQ_MAX
53  */
54 
55 /* kernel includes */
56 #include <linux/kernel.h>
57 #include <linux/module.h>
58 #include <linux/init.h>
59 #include <linux/slab.h>
60 #include <linux/input.h>
61 #include <linux/videodev2.h>
62 #include <media/v4l2-common.h>
63 #include <media/v4l2-ioctl.h>
64 #include <linux/usb.h>
65 #include <linux/version.h>	/* for KERNEL_VERSION MACRO */
66 
67 /* driver and module definitions */
68 #define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>"
69 #define DRIVER_DESC "AverMedia MR 800 USB FM radio driver"
70 #define DRIVER_VERSION "0.10"
71 #define RADIO_VERSION KERNEL_VERSION(0, 1, 0)
72 
73 MODULE_AUTHOR(DRIVER_AUTHOR);
74 MODULE_DESCRIPTION(DRIVER_DESC);
75 MODULE_LICENSE("GPL");
76 
77 #define USB_AMRADIO_VENDOR 0x07ca
78 #define USB_AMRADIO_PRODUCT 0xb800
79 
80 /* dev_warn macro with driver name */
81 #define MR800_DRIVER_NAME "radio-mr800"
82 #define amradio_dev_warn(dev, fmt, arg...)				\
83 		dev_warn(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
84 
85 /* Probably USB_TIMEOUT should be modified in module parameter */
86 #define BUFFER_LENGTH 8
87 #define USB_TIMEOUT 500
88 
89 /* Frequency limits in MHz -- these are European values.  For Japanese
90 devices, that would be 76 and 91.  */
91 #define FREQ_MIN  87.5
92 #define FREQ_MAX 108.0
93 #define FREQ_MUL 16000
94 
95 /*
96  * Commands that device should understand
97  * List isnt full and will be updated with implementation of new functions
98  */
99 #define AMRADIO_SET_FREQ	0xa4
100 #define AMRADIO_SET_MUTE	0xab
101 #define AMRADIO_SET_MONO	0xae
102 
103 /* Comfortable defines for amradio_set_mute */
104 #define AMRADIO_START		0x00
105 #define AMRADIO_STOP		0x01
106 
107 /* Comfortable defines for amradio_set_stereo */
108 #define WANT_STEREO		0x00
109 #define WANT_MONO		0x01
110 
111 /* module parameter */
112 static int radio_nr = -1;
113 module_param(radio_nr, int, 0);
114 MODULE_PARM_DESC(radio_nr, "Radio Nr");
115 
116 static struct v4l2_queryctrl radio_qctrl[] = {
117 	{
118 		.id            = V4L2_CID_AUDIO_MUTE,
119 		.name          = "Mute",
120 		.minimum       = 0,
121 		.maximum       = 1,
122 		.step	       = 1,
123 		.default_value = 1,
124 		.type          = V4L2_CTRL_TYPE_BOOLEAN,
125 	},
126 /* HINT: the disabled controls are only here to satify kradio and such apps */
127 	{	.id		= V4L2_CID_AUDIO_VOLUME,
128 		.flags		= V4L2_CTRL_FLAG_DISABLED,
129 	},
130 	{
131 		.id		= V4L2_CID_AUDIO_BALANCE,
132 		.flags		= V4L2_CTRL_FLAG_DISABLED,
133 	},
134 	{
135 		.id		= V4L2_CID_AUDIO_BASS,
136 		.flags		= V4L2_CTRL_FLAG_DISABLED,
137 	},
138 	{
139 		.id		= V4L2_CID_AUDIO_TREBLE,
140 		.flags		= V4L2_CTRL_FLAG_DISABLED,
141 	},
142 	{
143 		.id		= V4L2_CID_AUDIO_LOUDNESS,
144 		.flags		= V4L2_CTRL_FLAG_DISABLED,
145 	},
146 };
147 
148 static int usb_amradio_probe(struct usb_interface *intf,
149 			     const struct usb_device_id *id);
150 static void usb_amradio_disconnect(struct usb_interface *intf);
151 static int usb_amradio_open(struct file *file);
152 static int usb_amradio_close(struct file *file);
153 static int usb_amradio_suspend(struct usb_interface *intf,
154 				pm_message_t message);
155 static int usb_amradio_resume(struct usb_interface *intf);
156 
157 /* Data for one (physical) device */
158 struct amradio_device {
159 	/* reference to USB and video device */
160 	struct usb_device *usbdev;
161 	struct video_device *videodev;
162 
163 	unsigned char *buffer;
164 	struct mutex lock;	/* buffer locking */
165 	int curfreq;
166 	int stereo;
167 	int users;
168 	int removed;
169 	int muted;
170 };
171 
172 /* USB Device ID List */
173 static struct usb_device_id usb_amradio_device_table[] = {
174 	{USB_DEVICE_AND_INTERFACE_INFO(USB_AMRADIO_VENDOR, USB_AMRADIO_PRODUCT,
175 							USB_CLASS_HID, 0, 0) },
176 	{ }						/* Terminating entry */
177 };
178 
179 MODULE_DEVICE_TABLE(usb, usb_amradio_device_table);
180 
181 /* USB subsystem interface */
182 static struct usb_driver usb_amradio_driver = {
183 	.name			= MR800_DRIVER_NAME,
184 	.probe			= usb_amradio_probe,
185 	.disconnect		= usb_amradio_disconnect,
186 	.suspend		= usb_amradio_suspend,
187 	.resume			= usb_amradio_resume,
188 	.reset_resume		= usb_amradio_resume,
189 	.id_table		= usb_amradio_device_table,
190 	.supports_autosuspend	= 0,
191 };
192 
193 /* switch on/off the radio. Send 8 bytes to device */
194 static int amradio_set_mute(struct amradio_device *radio, char argument)
195 {
196 	int retval;
197 	int size;
198 
199 	/* safety check */
200 	if (radio->removed)
201 		return -EIO;
202 
203 	mutex_lock(&radio->lock);
204 
205 	radio->buffer[0] = 0x00;
206 	radio->buffer[1] = 0x55;
207 	radio->buffer[2] = 0xaa;
208 	radio->buffer[3] = 0x00;
209 	radio->buffer[4] = AMRADIO_SET_MUTE;
210 	radio->buffer[5] = argument;
211 	radio->buffer[6] = 0x00;
212 	radio->buffer[7] = 0x00;
213 
214 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
215 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
216 
217 	if (retval < 0 || size != BUFFER_LENGTH) {
218 		mutex_unlock(&radio->lock);
219 		return retval;
220 	}
221 
222 	radio->muted = argument;
223 
224 	mutex_unlock(&radio->lock);
225 
226 	return retval;
227 }
228 
229 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
230 static int amradio_setfreq(struct amradio_device *radio, int freq)
231 {
232 	int retval;
233 	int size;
234 	unsigned short freq_send = 0x10 + (freq >> 3) / 25;
235 
236 	/* safety check */
237 	if (radio->removed)
238 		return -EIO;
239 
240 	mutex_lock(&radio->lock);
241 
242 	radio->buffer[0] = 0x00;
243 	radio->buffer[1] = 0x55;
244 	radio->buffer[2] = 0xaa;
245 	radio->buffer[3] = 0x03;
246 	radio->buffer[4] = AMRADIO_SET_FREQ;
247 	radio->buffer[5] = 0x00;
248 	radio->buffer[6] = 0x00;
249 	radio->buffer[7] = 0x08;
250 
251 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
252 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
253 
254 	if (retval < 0 || size != BUFFER_LENGTH) {
255 		mutex_unlock(&radio->lock);
256 		return retval;
257 	}
258 
259 	/* frequency is calculated from freq_send and placed in first 2 bytes */
260 	radio->buffer[0] = (freq_send >> 8) & 0xff;
261 	radio->buffer[1] = freq_send & 0xff;
262 	radio->buffer[2] = 0x01;
263 	radio->buffer[3] = 0x00;
264 	radio->buffer[4] = 0x00;
265 	/* 5 and 6 bytes of buffer already = 0x00 */
266 	radio->buffer[7] = 0x00;
267 
268 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
269 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
270 
271 	if (retval < 0 || size != BUFFER_LENGTH) {
272 		mutex_unlock(&radio->lock);
273 		return retval;
274 	}
275 
276 	mutex_unlock(&radio->lock);
277 
278 	return retval;
279 }
280 
281 static int amradio_set_stereo(struct amradio_device *radio, char argument)
282 {
283 	int retval;
284 	int size;
285 
286 	/* safety check */
287 	if (radio->removed)
288 		return -EIO;
289 
290 	mutex_lock(&radio->lock);
291 
292 	radio->buffer[0] = 0x00;
293 	radio->buffer[1] = 0x55;
294 	radio->buffer[2] = 0xaa;
295 	radio->buffer[3] = 0x00;
296 	radio->buffer[4] = AMRADIO_SET_MONO;
297 	radio->buffer[5] = argument;
298 	radio->buffer[6] = 0x00;
299 	radio->buffer[7] = 0x00;
300 
301 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
302 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
303 
304 	if (retval < 0 || size != BUFFER_LENGTH) {
305 		radio->stereo = -1;
306 		mutex_unlock(&radio->lock);
307 		return retval;
308 	}
309 
310 	radio->stereo = 1;
311 
312 	mutex_unlock(&radio->lock);
313 
314 	return retval;
315 }
316 
317 /* Handle unplugging the device.
318  * We call video_unregister_device in any case.
319  * The last function called in this procedure is
320  * usb_amradio_device_release.
321  */
322 static void usb_amradio_disconnect(struct usb_interface *intf)
323 {
324 	struct amradio_device *radio = usb_get_intfdata(intf);
325 
326 	mutex_lock(&radio->lock);
327 	radio->removed = 1;
328 	mutex_unlock(&radio->lock);
329 
330 	usb_set_intfdata(intf, NULL);
331 	video_unregister_device(radio->videodev);
332 }
333 
334 /* vidioc_querycap - query device capabilities */
335 static int vidioc_querycap(struct file *file, void *priv,
336 					struct v4l2_capability *v)
337 {
338 	struct amradio_device *radio = video_drvdata(file);
339 
340 	strlcpy(v->driver, "radio-mr800", sizeof(v->driver));
341 	strlcpy(v->card, "AverMedia MR 800 USB FM Radio", sizeof(v->card));
342 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
343 	v->version = RADIO_VERSION;
344 	v->capabilities = V4L2_CAP_TUNER;
345 	return 0;
346 }
347 
348 /* vidioc_g_tuner - get tuner attributes */
349 static int vidioc_g_tuner(struct file *file, void *priv,
350 				struct v4l2_tuner *v)
351 {
352 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
353 	int retval;
354 
355 	/* safety check */
356 	if (radio->removed)
357 		return -EIO;
358 
359 	if (v->index > 0)
360 		return -EINVAL;
361 
362 /* TODO: Add function which look is signal stereo or not
363  * 	amradio_getstat(radio);
364  */
365 
366 /* we call amradio_set_stereo to set radio->stereo
367  * Honestly, amradio_getstat should cover this in future and
368  * amradio_set_stereo shouldn't be here
369  */
370 	retval = amradio_set_stereo(radio, WANT_STEREO);
371 	if (retval < 0)
372 		amradio_dev_warn(&radio->videodev->dev,
373 			"set stereo failed\n");
374 
375 	strcpy(v->name, "FM");
376 	v->type = V4L2_TUNER_RADIO;
377 	v->rangelow = FREQ_MIN * FREQ_MUL;
378 	v->rangehigh = FREQ_MAX * FREQ_MUL;
379 	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
380 	v->capability = V4L2_TUNER_CAP_LOW;
381 	if (radio->stereo)
382 		v->audmode = V4L2_TUNER_MODE_STEREO;
383 	else
384 		v->audmode = V4L2_TUNER_MODE_MONO;
385 	v->signal = 0xffff;     /* Can't get the signal strength, sad.. */
386 	v->afc = 0; /* Don't know what is this */
387 	return 0;
388 }
389 
390 /* vidioc_s_tuner - set tuner attributes */
391 static int vidioc_s_tuner(struct file *file, void *priv,
392 				struct v4l2_tuner *v)
393 {
394 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
395 	int retval;
396 
397 	/* safety check */
398 	if (radio->removed)
399 		return -EIO;
400 
401 	if (v->index > 0)
402 		return -EINVAL;
403 
404 	/* mono/stereo selector */
405 	switch (v->audmode) {
406 	case V4L2_TUNER_MODE_MONO:
407 		retval = amradio_set_stereo(radio, WANT_MONO);
408 		if (retval < 0)
409 			amradio_dev_warn(&radio->videodev->dev,
410 				"set mono failed\n");
411 		break;
412 	case V4L2_TUNER_MODE_STEREO:
413 		retval = amradio_set_stereo(radio, WANT_STEREO);
414 		if (retval < 0)
415 			amradio_dev_warn(&radio->videodev->dev,
416 				"set stereo failed\n");
417 		break;
418 	default:
419 		return -EINVAL;
420 	}
421 
422 	return 0;
423 }
424 
425 /* vidioc_s_frequency - set tuner radio frequency */
426 static int vidioc_s_frequency(struct file *file, void *priv,
427 				struct v4l2_frequency *f)
428 {
429 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
430 	int retval;
431 
432 	/* safety check */
433 	if (radio->removed)
434 		return -EIO;
435 
436 	mutex_lock(&radio->lock);
437 	radio->curfreq = f->frequency;
438 	mutex_unlock(&radio->lock);
439 
440 	retval = amradio_setfreq(radio, radio->curfreq);
441 	if (retval < 0)
442 		amradio_dev_warn(&radio->videodev->dev,
443 			"set frequency failed\n");
444 	return 0;
445 }
446 
447 /* vidioc_g_frequency - get tuner radio frequency */
448 static int vidioc_g_frequency(struct file *file, void *priv,
449 				struct v4l2_frequency *f)
450 {
451 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
452 
453 	/* safety check */
454 	if (radio->removed)
455 		return -EIO;
456 
457 	f->type = V4L2_TUNER_RADIO;
458 	f->frequency = radio->curfreq;
459 	return 0;
460 }
461 
462 /* vidioc_queryctrl - enumerate control items */
463 static int vidioc_queryctrl(struct file *file, void *priv,
464 				struct v4l2_queryctrl *qc)
465 {
466 	int i;
467 
468 	for (i = 0; i < ARRAY_SIZE(radio_qctrl); i++) {
469 		if (qc->id && qc->id == radio_qctrl[i].id) {
470 			memcpy(qc, &(radio_qctrl[i]), sizeof(*qc));
471 			return 0;
472 		}
473 	}
474 	return -EINVAL;
475 }
476 
477 /* vidioc_g_ctrl - get the value of a control */
478 static int vidioc_g_ctrl(struct file *file, void *priv,
479 				struct v4l2_control *ctrl)
480 {
481 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
482 
483 	/* safety check */
484 	if (radio->removed)
485 		return -EIO;
486 
487 	switch (ctrl->id) {
488 	case V4L2_CID_AUDIO_MUTE:
489 		ctrl->value = radio->muted;
490 		return 0;
491 	}
492 	return -EINVAL;
493 }
494 
495 /* vidioc_s_ctrl - set the value of a control */
496 static int vidioc_s_ctrl(struct file *file, void *priv,
497 				struct v4l2_control *ctrl)
498 {
499 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
500 	int retval;
501 
502 	/* safety check */
503 	if (radio->removed)
504 		return -EIO;
505 
506 	switch (ctrl->id) {
507 	case V4L2_CID_AUDIO_MUTE:
508 		if (ctrl->value) {
509 			retval = amradio_set_mute(radio, AMRADIO_STOP);
510 			if (retval < 0) {
511 				amradio_dev_warn(&radio->videodev->dev,
512 					"amradio_stop failed\n");
513 				return -1;
514 			}
515 		} else {
516 			retval = amradio_set_mute(radio, AMRADIO_START);
517 			if (retval < 0) {
518 				amradio_dev_warn(&radio->videodev->dev,
519 					"amradio_start failed\n");
520 				return -1;
521 			}
522 		}
523 		return 0;
524 	}
525 	return -EINVAL;
526 }
527 
528 /* vidioc_g_audio - get audio attributes */
529 static int vidioc_g_audio(struct file *file, void *priv,
530 				struct v4l2_audio *a)
531 {
532 	if (a->index > 1)
533 		return -EINVAL;
534 
535 	strcpy(a->name, "Radio");
536 	a->capability = V4L2_AUDCAP_STEREO;
537 	return 0;
538 }
539 
540 /* vidioc_s_audio - set audio attributes  */
541 static int vidioc_s_audio(struct file *file, void *priv,
542 					struct v4l2_audio *a)
543 {
544 	if (a->index != 0)
545 		return -EINVAL;
546 	return 0;
547 }
548 
549 /* vidioc_g_input - get input */
550 static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
551 {
552 	*i = 0;
553 	return 0;
554 }
555 
556 /* vidioc_s_input - set input */
557 static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
558 {
559 	if (i != 0)
560 		return -EINVAL;
561 	return 0;
562 }
563 
564 /* open device - amradio_start() and amradio_setfreq() */
565 static int usb_amradio_open(struct file *file)
566 {
567 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
568 	int retval;
569 
570 	lock_kernel();
571 
572 	radio->users = 1;
573 	radio->muted = 1;
574 
575 	retval = amradio_set_mute(radio, AMRADIO_START);
576 	if (retval < 0) {
577 		amradio_dev_warn(&radio->videodev->dev,
578 			"radio did not start up properly\n");
579 		radio->users = 0;
580 		unlock_kernel();
581 		return -EIO;
582 	}
583 
584 	retval = amradio_set_stereo(radio, WANT_STEREO);
585 	if (retval < 0)
586 		amradio_dev_warn(&radio->videodev->dev,
587 			"set stereo failed\n");
588 
589 	retval = amradio_setfreq(radio, radio->curfreq);
590 	if (retval < 0)
591 		amradio_dev_warn(&radio->videodev->dev,
592 			"set frequency failed\n");
593 
594 	unlock_kernel();
595 	return 0;
596 }
597 
598 /*close device */
599 static int usb_amradio_close(struct file *file)
600 {
601 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
602 	int retval;
603 
604 	if (!radio)
605 		return -ENODEV;
606 
607 	mutex_lock(&radio->lock);
608 	radio->users = 0;
609 	mutex_unlock(&radio->lock);
610 
611 	if (!radio->removed) {
612 		retval = amradio_set_mute(radio, AMRADIO_STOP);
613 		if (retval < 0)
614 			amradio_dev_warn(&radio->videodev->dev,
615 				"amradio_stop failed\n");
616 	}
617 
618 	return 0;
619 }
620 
621 /* Suspend device - stop device. Need to be checked and fixed */
622 static int usb_amradio_suspend(struct usb_interface *intf, pm_message_t message)
623 {
624 	struct amradio_device *radio = usb_get_intfdata(intf);
625 	int retval;
626 
627 	retval = amradio_set_mute(radio, AMRADIO_STOP);
628 	if (retval < 0)
629 		dev_warn(&intf->dev, "amradio_stop failed\n");
630 
631 	dev_info(&intf->dev, "going into suspend..\n");
632 
633 	return 0;
634 }
635 
636 /* Resume device - start device. Need to be checked and fixed */
637 static int usb_amradio_resume(struct usb_interface *intf)
638 {
639 	struct amradio_device *radio = usb_get_intfdata(intf);
640 	int retval;
641 
642 	retval = amradio_set_mute(radio, AMRADIO_START);
643 	if (retval < 0)
644 		dev_warn(&intf->dev, "amradio_start failed\n");
645 
646 	dev_info(&intf->dev, "coming out of suspend..\n");
647 
648 	return 0;
649 }
650 
651 /* File system interface */
652 static const struct v4l2_file_operations usb_amradio_fops = {
653 	.owner		= THIS_MODULE,
654 	.open		= usb_amradio_open,
655 	.release	= usb_amradio_close,
656 	.ioctl		= video_ioctl2,
657 };
658 
659 static const struct v4l2_ioctl_ops usb_amradio_ioctl_ops = {
660 	.vidioc_querycap    = vidioc_querycap,
661 	.vidioc_g_tuner     = vidioc_g_tuner,
662 	.vidioc_s_tuner     = vidioc_s_tuner,
663 	.vidioc_g_frequency = vidioc_g_frequency,
664 	.vidioc_s_frequency = vidioc_s_frequency,
665 	.vidioc_queryctrl   = vidioc_queryctrl,
666 	.vidioc_g_ctrl      = vidioc_g_ctrl,
667 	.vidioc_s_ctrl      = vidioc_s_ctrl,
668 	.vidioc_g_audio     = vidioc_g_audio,
669 	.vidioc_s_audio     = vidioc_s_audio,
670 	.vidioc_g_input     = vidioc_g_input,
671 	.vidioc_s_input     = vidioc_s_input,
672 };
673 
674 static void usb_amradio_device_release(struct video_device *videodev)
675 {
676 	struct amradio_device *radio = video_get_drvdata(videodev);
677 
678 	/* we call v4l to free radio->videodev */
679 	video_device_release(videodev);
680 
681 	/* free rest memory */
682 	kfree(radio->buffer);
683 	kfree(radio);
684 }
685 
686 /* V4L2 interface */
687 static struct video_device amradio_videodev_template = {
688 	.name		= "AverMedia MR 800 USB FM Radio",
689 	.fops		= &usb_amradio_fops,
690 	.ioctl_ops 	= &usb_amradio_ioctl_ops,
691 	.release	= usb_amradio_device_release,
692 };
693 
694 /* check if the device is present and register with v4l and usb if it is */
695 static int usb_amradio_probe(struct usb_interface *intf,
696 				const struct usb_device_id *id)
697 {
698 	struct amradio_device *radio;
699 	int retval;
700 
701 	radio = kmalloc(sizeof(struct amradio_device), GFP_KERNEL);
702 
703 	if (!radio) {
704 		dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
705 		return -ENOMEM;
706 	}
707 
708 	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
709 
710 	if (!radio->buffer) {
711 		dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
712 		kfree(radio);
713 		return -ENOMEM;
714 	}
715 
716 	radio->videodev = video_device_alloc();
717 
718 	if (!radio->videodev) {
719 		dev_err(&intf->dev, "video_device_alloc failed\n");
720 		kfree(radio->buffer);
721 		kfree(radio);
722 		return -ENOMEM;
723 	}
724 
725 	memcpy(radio->videodev, &amradio_videodev_template,
726 		sizeof(amradio_videodev_template));
727 
728 	radio->removed = 0;
729 	radio->users = 0;
730 	radio->usbdev = interface_to_usbdev(intf);
731 	radio->curfreq = 95.16 * FREQ_MUL;
732 	radio->stereo = -1;
733 
734 	mutex_init(&radio->lock);
735 
736 	video_set_drvdata(radio->videodev, radio);
737 	retval = video_register_device(radio->videodev,	VFL_TYPE_RADIO,	radio_nr);
738 	if (retval < 0) {
739 		dev_err(&intf->dev, "could not register video device\n");
740 		video_device_release(radio->videodev);
741 		kfree(radio->buffer);
742 		kfree(radio);
743 		return -EIO;
744 	}
745 
746 	usb_set_intfdata(intf, radio);
747 	return 0;
748 }
749 
750 static int __init amradio_init(void)
751 {
752 	int retval = usb_register(&usb_amradio_driver);
753 
754 	pr_info(KBUILD_MODNAME
755 		": version " DRIVER_VERSION " " DRIVER_DESC "\n");
756 
757 	if (retval)
758 		pr_err(KBUILD_MODNAME
759 			": usb_register failed. Error number %d\n", retval);
760 
761 	return retval;
762 }
763 
764 static void __exit amradio_exit(void)
765 {
766 	usb_deregister(&usb_amradio_driver);
767 }
768 
769 module_init(amradio_init);
770 module_exit(amradio_exit);
771 
772