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  * Version 0.11:	Converted to v4l2_device.
47  *
48  * Many things to do:
49  * 	- Correct power managment of device (suspend & resume)
50  * 	- Add code for scanning and smooth tuning
51  * 	- Add code for sensitivity value
52  * 	- Correct mistakes
53  * 	- In Japan another FREQ_MIN and FREQ_MAX
54  */
55 
56 /* kernel includes */
57 #include <linux/kernel.h>
58 #include <linux/module.h>
59 #include <linux/init.h>
60 #include <linux/slab.h>
61 #include <linux/input.h>
62 #include <linux/videodev2.h>
63 #include <media/v4l2-device.h>
64 #include <media/v4l2-ioctl.h>
65 #include <linux/usb.h>
66 #include <linux/version.h>	/* for KERNEL_VERSION MACRO */
67 
68 /* driver and module definitions */
69 #define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>"
70 #define DRIVER_DESC "AverMedia MR 800 USB FM radio driver"
71 #define DRIVER_VERSION "0.11"
72 #define RADIO_VERSION KERNEL_VERSION(0, 1, 1)
73 
74 MODULE_AUTHOR(DRIVER_AUTHOR);
75 MODULE_DESCRIPTION(DRIVER_DESC);
76 MODULE_LICENSE("GPL");
77 
78 #define USB_AMRADIO_VENDOR 0x07ca
79 #define USB_AMRADIO_PRODUCT 0xb800
80 
81 /* dev_warn macro with driver name */
82 #define MR800_DRIVER_NAME "radio-mr800"
83 #define amradio_dev_warn(dev, fmt, arg...)				\
84 		dev_warn(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
85 
86 /* Probably USB_TIMEOUT should be modified in module parameter */
87 #define BUFFER_LENGTH 8
88 #define USB_TIMEOUT 500
89 
90 /* Frequency limits in MHz -- these are European values.  For Japanese
91 devices, that would be 76 and 91.  */
92 #define FREQ_MIN  87.5
93 #define FREQ_MAX 108.0
94 #define FREQ_MUL 16000
95 
96 /*
97  * Commands that device should understand
98  * List isnt full and will be updated with implementation of new functions
99  */
100 #define AMRADIO_SET_FREQ	0xa4
101 #define AMRADIO_SET_MUTE	0xab
102 #define AMRADIO_SET_MONO	0xae
103 
104 /* Comfortable defines for amradio_set_mute */
105 #define AMRADIO_START		0x00
106 #define AMRADIO_STOP		0x01
107 
108 /* Comfortable defines for amradio_set_stereo */
109 #define WANT_STEREO		0x00
110 #define WANT_MONO		0x01
111 
112 /* module parameter */
113 static int radio_nr = -1;
114 module_param(radio_nr, int, 0);
115 MODULE_PARM_DESC(radio_nr, "Radio Nr");
116 
117 static int usb_amradio_probe(struct usb_interface *intf,
118 			     const struct usb_device_id *id);
119 static void usb_amradio_disconnect(struct usb_interface *intf);
120 static int usb_amradio_open(struct file *file);
121 static int usb_amradio_close(struct file *file);
122 static int usb_amradio_suspend(struct usb_interface *intf,
123 				pm_message_t message);
124 static int usb_amradio_resume(struct usb_interface *intf);
125 
126 /* Data for one (physical) device */
127 struct amradio_device {
128 	/* reference to USB and video device */
129 	struct usb_device *usbdev;
130 	struct video_device *videodev;
131 	struct v4l2_device v4l2_dev;
132 
133 	unsigned char *buffer;
134 	struct mutex lock;	/* buffer locking */
135 	int curfreq;
136 	int stereo;
137 	int users;
138 	int removed;
139 	int muted;
140 };
141 
142 /* USB Device ID List */
143 static struct usb_device_id usb_amradio_device_table[] = {
144 	{USB_DEVICE_AND_INTERFACE_INFO(USB_AMRADIO_VENDOR, USB_AMRADIO_PRODUCT,
145 							USB_CLASS_HID, 0, 0) },
146 	{ }						/* Terminating entry */
147 };
148 
149 MODULE_DEVICE_TABLE(usb, usb_amradio_device_table);
150 
151 /* USB subsystem interface */
152 static struct usb_driver usb_amradio_driver = {
153 	.name			= MR800_DRIVER_NAME,
154 	.probe			= usb_amradio_probe,
155 	.disconnect		= usb_amradio_disconnect,
156 	.suspend		= usb_amradio_suspend,
157 	.resume			= usb_amradio_resume,
158 	.reset_resume		= usb_amradio_resume,
159 	.id_table		= usb_amradio_device_table,
160 	.supports_autosuspend	= 0,
161 };
162 
163 /* switch on/off the radio. Send 8 bytes to device */
164 static int amradio_set_mute(struct amradio_device *radio, char argument)
165 {
166 	int retval;
167 	int size;
168 
169 	/* safety check */
170 	if (radio->removed)
171 		return -EIO;
172 
173 	mutex_lock(&radio->lock);
174 
175 	radio->buffer[0] = 0x00;
176 	radio->buffer[1] = 0x55;
177 	radio->buffer[2] = 0xaa;
178 	radio->buffer[3] = 0x00;
179 	radio->buffer[4] = AMRADIO_SET_MUTE;
180 	radio->buffer[5] = argument;
181 	radio->buffer[6] = 0x00;
182 	radio->buffer[7] = 0x00;
183 
184 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
185 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
186 
187 	if (retval < 0 || size != BUFFER_LENGTH) {
188 		mutex_unlock(&radio->lock);
189 		return retval;
190 	}
191 
192 	radio->muted = argument;
193 
194 	mutex_unlock(&radio->lock);
195 
196 	return retval;
197 }
198 
199 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
200 static int amradio_setfreq(struct amradio_device *radio, int freq)
201 {
202 	int retval;
203 	int size;
204 	unsigned short freq_send = 0x10 + (freq >> 3) / 25;
205 
206 	/* safety check */
207 	if (radio->removed)
208 		return -EIO;
209 
210 	mutex_lock(&radio->lock);
211 
212 	radio->buffer[0] = 0x00;
213 	radio->buffer[1] = 0x55;
214 	radio->buffer[2] = 0xaa;
215 	radio->buffer[3] = 0x03;
216 	radio->buffer[4] = AMRADIO_SET_FREQ;
217 	radio->buffer[5] = 0x00;
218 	radio->buffer[6] = 0x00;
219 	radio->buffer[7] = 0x08;
220 
221 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
222 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
223 
224 	if (retval < 0 || size != BUFFER_LENGTH) {
225 		mutex_unlock(&radio->lock);
226 		return retval;
227 	}
228 
229 	/* frequency is calculated from freq_send and placed in first 2 bytes */
230 	radio->buffer[0] = (freq_send >> 8) & 0xff;
231 	radio->buffer[1] = freq_send & 0xff;
232 	radio->buffer[2] = 0x01;
233 	radio->buffer[3] = 0x00;
234 	radio->buffer[4] = 0x00;
235 	/* 5 and 6 bytes of buffer already = 0x00 */
236 	radio->buffer[7] = 0x00;
237 
238 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
239 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
240 
241 	if (retval < 0 || size != BUFFER_LENGTH) {
242 		mutex_unlock(&radio->lock);
243 		return retval;
244 	}
245 
246 	mutex_unlock(&radio->lock);
247 
248 	return retval;
249 }
250 
251 static int amradio_set_stereo(struct amradio_device *radio, char argument)
252 {
253 	int retval;
254 	int size;
255 
256 	/* safety check */
257 	if (radio->removed)
258 		return -EIO;
259 
260 	mutex_lock(&radio->lock);
261 
262 	radio->buffer[0] = 0x00;
263 	radio->buffer[1] = 0x55;
264 	radio->buffer[2] = 0xaa;
265 	radio->buffer[3] = 0x00;
266 	radio->buffer[4] = AMRADIO_SET_MONO;
267 	radio->buffer[5] = argument;
268 	radio->buffer[6] = 0x00;
269 	radio->buffer[7] = 0x00;
270 
271 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
272 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
273 
274 	if (retval < 0 || size != BUFFER_LENGTH) {
275 		radio->stereo = -1;
276 		mutex_unlock(&radio->lock);
277 		return retval;
278 	}
279 
280 	radio->stereo = 1;
281 
282 	mutex_unlock(&radio->lock);
283 
284 	return retval;
285 }
286 
287 /* Handle unplugging the device.
288  * We call video_unregister_device in any case.
289  * The last function called in this procedure is
290  * usb_amradio_device_release.
291  */
292 static void usb_amradio_disconnect(struct usb_interface *intf)
293 {
294 	struct amradio_device *radio = usb_get_intfdata(intf);
295 
296 	mutex_lock(&radio->lock);
297 	radio->removed = 1;
298 	mutex_unlock(&radio->lock);
299 
300 	usb_set_intfdata(intf, NULL);
301 	video_unregister_device(radio->videodev);
302 	v4l2_device_disconnect(&radio->v4l2_dev);
303 }
304 
305 /* vidioc_querycap - query device capabilities */
306 static int vidioc_querycap(struct file *file, void *priv,
307 					struct v4l2_capability *v)
308 {
309 	struct amradio_device *radio = video_drvdata(file);
310 
311 	strlcpy(v->driver, "radio-mr800", sizeof(v->driver));
312 	strlcpy(v->card, "AverMedia MR 800 USB FM Radio", sizeof(v->card));
313 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
314 	v->version = RADIO_VERSION;
315 	v->capabilities = V4L2_CAP_TUNER;
316 	return 0;
317 }
318 
319 /* vidioc_g_tuner - get tuner attributes */
320 static int vidioc_g_tuner(struct file *file, void *priv,
321 				struct v4l2_tuner *v)
322 {
323 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
324 	int retval;
325 
326 	/* safety check */
327 	if (radio->removed)
328 		return -EIO;
329 
330 	if (v->index > 0)
331 		return -EINVAL;
332 
333 /* TODO: Add function which look is signal stereo or not
334  * 	amradio_getstat(radio);
335  */
336 
337 /* we call amradio_set_stereo to set radio->stereo
338  * Honestly, amradio_getstat should cover this in future and
339  * amradio_set_stereo shouldn't be here
340  */
341 	retval = amradio_set_stereo(radio, WANT_STEREO);
342 	if (retval < 0)
343 		amradio_dev_warn(&radio->videodev->dev,
344 			"set stereo failed\n");
345 
346 	strcpy(v->name, "FM");
347 	v->type = V4L2_TUNER_RADIO;
348 	v->rangelow = FREQ_MIN * FREQ_MUL;
349 	v->rangehigh = FREQ_MAX * FREQ_MUL;
350 	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
351 	v->capability = V4L2_TUNER_CAP_LOW;
352 	if (radio->stereo)
353 		v->audmode = V4L2_TUNER_MODE_STEREO;
354 	else
355 		v->audmode = V4L2_TUNER_MODE_MONO;
356 	v->signal = 0xffff;     /* Can't get the signal strength, sad.. */
357 	v->afc = 0; /* Don't know what is this */
358 	return 0;
359 }
360 
361 /* vidioc_s_tuner - set tuner attributes */
362 static int vidioc_s_tuner(struct file *file, void *priv,
363 				struct v4l2_tuner *v)
364 {
365 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
366 	int retval;
367 
368 	/* safety check */
369 	if (radio->removed)
370 		return -EIO;
371 
372 	if (v->index > 0)
373 		return -EINVAL;
374 
375 	/* mono/stereo selector */
376 	switch (v->audmode) {
377 	case V4L2_TUNER_MODE_MONO:
378 		retval = amradio_set_stereo(radio, WANT_MONO);
379 		if (retval < 0)
380 			amradio_dev_warn(&radio->videodev->dev,
381 				"set mono failed\n");
382 		break;
383 	case V4L2_TUNER_MODE_STEREO:
384 		retval = amradio_set_stereo(radio, WANT_STEREO);
385 		if (retval < 0)
386 			amradio_dev_warn(&radio->videodev->dev,
387 				"set stereo failed\n");
388 		break;
389 	default:
390 		return -EINVAL;
391 	}
392 
393 	return 0;
394 }
395 
396 /* vidioc_s_frequency - set tuner radio frequency */
397 static int vidioc_s_frequency(struct file *file, void *priv,
398 				struct v4l2_frequency *f)
399 {
400 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
401 	int retval;
402 
403 	/* safety check */
404 	if (radio->removed)
405 		return -EIO;
406 
407 	mutex_lock(&radio->lock);
408 	radio->curfreq = f->frequency;
409 	mutex_unlock(&radio->lock);
410 
411 	retval = amradio_setfreq(radio, radio->curfreq);
412 	if (retval < 0)
413 		amradio_dev_warn(&radio->videodev->dev,
414 			"set frequency failed\n");
415 	return 0;
416 }
417 
418 /* vidioc_g_frequency - get tuner radio frequency */
419 static int vidioc_g_frequency(struct file *file, void *priv,
420 				struct v4l2_frequency *f)
421 {
422 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
423 
424 	/* safety check */
425 	if (radio->removed)
426 		return -EIO;
427 
428 	f->type = V4L2_TUNER_RADIO;
429 	f->frequency = radio->curfreq;
430 	return 0;
431 }
432 
433 /* vidioc_queryctrl - enumerate control items */
434 static int vidioc_queryctrl(struct file *file, void *priv,
435 				struct v4l2_queryctrl *qc)
436 {
437 	switch (qc->id) {
438 	case V4L2_CID_AUDIO_MUTE:
439 		return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
440 	}
441 
442 	return -EINVAL;
443 }
444 
445 /* vidioc_g_ctrl - get the value of a control */
446 static int vidioc_g_ctrl(struct file *file, void *priv,
447 				struct v4l2_control *ctrl)
448 {
449 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
450 
451 	/* safety check */
452 	if (radio->removed)
453 		return -EIO;
454 
455 	switch (ctrl->id) {
456 	case V4L2_CID_AUDIO_MUTE:
457 		ctrl->value = radio->muted;
458 		return 0;
459 	}
460 	return -EINVAL;
461 }
462 
463 /* vidioc_s_ctrl - set the value of a control */
464 static int vidioc_s_ctrl(struct file *file, void *priv,
465 				struct v4l2_control *ctrl)
466 {
467 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
468 	int retval;
469 
470 	/* safety check */
471 	if (radio->removed)
472 		return -EIO;
473 
474 	switch (ctrl->id) {
475 	case V4L2_CID_AUDIO_MUTE:
476 		if (ctrl->value) {
477 			retval = amradio_set_mute(radio, AMRADIO_STOP);
478 			if (retval < 0) {
479 				amradio_dev_warn(&radio->videodev->dev,
480 					"amradio_stop failed\n");
481 				return -1;
482 			}
483 		} else {
484 			retval = amradio_set_mute(radio, AMRADIO_START);
485 			if (retval < 0) {
486 				amradio_dev_warn(&radio->videodev->dev,
487 					"amradio_start failed\n");
488 				return -1;
489 			}
490 		}
491 		return 0;
492 	}
493 	return -EINVAL;
494 }
495 
496 /* vidioc_g_audio - get audio attributes */
497 static int vidioc_g_audio(struct file *file, void *priv,
498 				struct v4l2_audio *a)
499 {
500 	if (a->index > 1)
501 		return -EINVAL;
502 
503 	strcpy(a->name, "Radio");
504 	a->capability = V4L2_AUDCAP_STEREO;
505 	return 0;
506 }
507 
508 /* vidioc_s_audio - set audio attributes  */
509 static int vidioc_s_audio(struct file *file, void *priv,
510 					struct v4l2_audio *a)
511 {
512 	if (a->index != 0)
513 		return -EINVAL;
514 	return 0;
515 }
516 
517 /* vidioc_g_input - get input */
518 static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
519 {
520 	*i = 0;
521 	return 0;
522 }
523 
524 /* vidioc_s_input - set input */
525 static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
526 {
527 	if (i != 0)
528 		return -EINVAL;
529 	return 0;
530 }
531 
532 /* open device - amradio_start() and amradio_setfreq() */
533 static int usb_amradio_open(struct file *file)
534 {
535 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
536 	int retval;
537 
538 	lock_kernel();
539 
540 	radio->users = 1;
541 	radio->muted = 1;
542 
543 	retval = amradio_set_mute(radio, AMRADIO_START);
544 	if (retval < 0) {
545 		amradio_dev_warn(&radio->videodev->dev,
546 			"radio did not start up properly\n");
547 		radio->users = 0;
548 		unlock_kernel();
549 		return -EIO;
550 	}
551 
552 	retval = amradio_set_stereo(radio, WANT_STEREO);
553 	if (retval < 0)
554 		amradio_dev_warn(&radio->videodev->dev,
555 			"set stereo failed\n");
556 
557 	retval = amradio_setfreq(radio, radio->curfreq);
558 	if (retval < 0)
559 		amradio_dev_warn(&radio->videodev->dev,
560 			"set frequency failed\n");
561 
562 	unlock_kernel();
563 	return 0;
564 }
565 
566 /*close device */
567 static int usb_amradio_close(struct file *file)
568 {
569 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
570 	int retval;
571 
572 	if (!radio)
573 		return -ENODEV;
574 
575 	mutex_lock(&radio->lock);
576 	radio->users = 0;
577 	mutex_unlock(&radio->lock);
578 
579 	if (!radio->removed) {
580 		retval = amradio_set_mute(radio, AMRADIO_STOP);
581 		if (retval < 0)
582 			amradio_dev_warn(&radio->videodev->dev,
583 				"amradio_stop failed\n");
584 	}
585 
586 	return 0;
587 }
588 
589 /* Suspend device - stop device. Need to be checked and fixed */
590 static int usb_amradio_suspend(struct usb_interface *intf, pm_message_t message)
591 {
592 	struct amradio_device *radio = usb_get_intfdata(intf);
593 	int retval;
594 
595 	retval = amradio_set_mute(radio, AMRADIO_STOP);
596 	if (retval < 0)
597 		dev_warn(&intf->dev, "amradio_stop failed\n");
598 
599 	dev_info(&intf->dev, "going into suspend..\n");
600 
601 	return 0;
602 }
603 
604 /* Resume device - start device. Need to be checked and fixed */
605 static int usb_amradio_resume(struct usb_interface *intf)
606 {
607 	struct amradio_device *radio = usb_get_intfdata(intf);
608 	int retval;
609 
610 	retval = amradio_set_mute(radio, AMRADIO_START);
611 	if (retval < 0)
612 		dev_warn(&intf->dev, "amradio_start failed\n");
613 
614 	dev_info(&intf->dev, "coming out of suspend..\n");
615 
616 	return 0;
617 }
618 
619 /* File system interface */
620 static const struct v4l2_file_operations usb_amradio_fops = {
621 	.owner		= THIS_MODULE,
622 	.open		= usb_amradio_open,
623 	.release	= usb_amradio_close,
624 	.ioctl		= video_ioctl2,
625 };
626 
627 static const struct v4l2_ioctl_ops usb_amradio_ioctl_ops = {
628 	.vidioc_querycap    = vidioc_querycap,
629 	.vidioc_g_tuner     = vidioc_g_tuner,
630 	.vidioc_s_tuner     = vidioc_s_tuner,
631 	.vidioc_g_frequency = vidioc_g_frequency,
632 	.vidioc_s_frequency = vidioc_s_frequency,
633 	.vidioc_queryctrl   = vidioc_queryctrl,
634 	.vidioc_g_ctrl      = vidioc_g_ctrl,
635 	.vidioc_s_ctrl      = vidioc_s_ctrl,
636 	.vidioc_g_audio     = vidioc_g_audio,
637 	.vidioc_s_audio     = vidioc_s_audio,
638 	.vidioc_g_input     = vidioc_g_input,
639 	.vidioc_s_input     = vidioc_s_input,
640 };
641 
642 static void usb_amradio_video_device_release(struct video_device *videodev)
643 {
644 	struct amradio_device *radio = video_get_drvdata(videodev);
645 
646 	/* we call v4l to free radio->videodev */
647 	video_device_release(videodev);
648 
649 	v4l2_device_unregister(&radio->v4l2_dev);
650 
651 	/* free rest memory */
652 	kfree(radio->buffer);
653 	kfree(radio);
654 }
655 
656 /* check if the device is present and register with v4l and usb if it is */
657 static int usb_amradio_probe(struct usb_interface *intf,
658 				const struct usb_device_id *id)
659 {
660 	struct amradio_device *radio;
661 	struct v4l2_device *v4l2_dev;
662 	int retval;
663 
664 	radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);
665 
666 	if (!radio) {
667 		dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
668 		return -ENOMEM;
669 	}
670 
671 	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
672 
673 	if (!radio->buffer) {
674 		dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
675 		kfree(radio);
676 		return -ENOMEM;
677 	}
678 
679 	v4l2_dev = &radio->v4l2_dev;
680 	retval = v4l2_device_register(&intf->dev, v4l2_dev);
681 	if (retval < 0) {
682 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
683 		kfree(radio->buffer);
684 		kfree(radio);
685 		return retval;
686 	}
687 
688 	radio->videodev = video_device_alloc();
689 
690 	if (!radio->videodev) {
691 		dev_err(&intf->dev, "video_device_alloc failed\n");
692 		kfree(radio->buffer);
693 		kfree(radio);
694 		return -ENOMEM;
695 	}
696 
697 	strlcpy(radio->videodev->name, v4l2_dev->name, sizeof(radio->videodev->name));
698 	radio->videodev->v4l2_dev = v4l2_dev;
699 	radio->videodev->fops = &usb_amradio_fops;
700 	radio->videodev->ioctl_ops = &usb_amradio_ioctl_ops;
701 	radio->videodev->release = usb_amradio_video_device_release;
702 
703 	radio->removed = 0;
704 	radio->users = 0;
705 	radio->usbdev = interface_to_usbdev(intf);
706 	radio->curfreq = 95.16 * FREQ_MUL;
707 	radio->stereo = -1;
708 
709 	mutex_init(&radio->lock);
710 
711 	video_set_drvdata(radio->videodev, radio);
712 
713 	retval = video_register_device(radio->videodev,	VFL_TYPE_RADIO,	radio_nr);
714 	if (retval < 0) {
715 		dev_err(&intf->dev, "could not register video device\n");
716 		video_device_release(radio->videodev);
717 		v4l2_device_unregister(v4l2_dev);
718 		kfree(radio->buffer);
719 		kfree(radio);
720 		return -EIO;
721 	}
722 
723 	usb_set_intfdata(intf, radio);
724 	return 0;
725 }
726 
727 static int __init amradio_init(void)
728 {
729 	int retval = usb_register(&usb_amradio_driver);
730 
731 	pr_info(KBUILD_MODNAME
732 		": version " DRIVER_VERSION " " DRIVER_DESC "\n");
733 
734 	if (retval)
735 		pr_err(KBUILD_MODNAME
736 			": usb_register failed. Error number %d\n", retval);
737 
738 	return retval;
739 }
740 
741 static void __exit amradio_exit(void)
742 {
743 	usb_deregister(&usb_amradio_driver);
744 }
745 
746 module_init(amradio_init);
747 module_exit(amradio_exit);
748 
749