xref: /openbmc/linux/drivers/media/radio/radio-mr800.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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 through 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 management 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 #include <linux/mutex.h>
68 
69 /* driver and module definitions */
70 #define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>"
71 #define DRIVER_DESC "AverMedia MR 800 USB FM radio driver"
72 #define DRIVER_VERSION "0.11"
73 #define RADIO_VERSION KERNEL_VERSION(0, 1, 1)
74 
75 MODULE_AUTHOR(DRIVER_AUTHOR);
76 MODULE_DESCRIPTION(DRIVER_DESC);
77 MODULE_LICENSE("GPL");
78 
79 #define USB_AMRADIO_VENDOR 0x07ca
80 #define USB_AMRADIO_PRODUCT 0xb800
81 
82 /* dev_warn macro with driver name */
83 #define MR800_DRIVER_NAME "radio-mr800"
84 #define amradio_dev_warn(dev, fmt, arg...)				\
85 		dev_warn(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
86 
87 #define amradio_dev_err(dev, fmt, arg...) \
88 		dev_err(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
89 
90 /* Probably USB_TIMEOUT should be modified in module parameter */
91 #define BUFFER_LENGTH 8
92 #define USB_TIMEOUT 500
93 
94 /* Frequency limits in MHz -- these are European values.  For Japanese
95 devices, that would be 76 and 91.  */
96 #define FREQ_MIN  87.5
97 #define FREQ_MAX 108.0
98 #define FREQ_MUL 16000
99 
100 /*
101  * Commands that device should understand
102  * List isnt full and will be updated with implementation of new functions
103  */
104 #define AMRADIO_SET_FREQ	0xa4
105 #define AMRADIO_SET_MUTE	0xab
106 #define AMRADIO_SET_MONO	0xae
107 
108 /* Comfortable defines for amradio_set_mute */
109 #define AMRADIO_START		0x00
110 #define AMRADIO_STOP		0x01
111 
112 /* Comfortable defines for amradio_set_stereo */
113 #define WANT_STEREO		0x00
114 #define WANT_MONO		0x01
115 
116 /* module parameter */
117 static int radio_nr = -1;
118 module_param(radio_nr, int, 0);
119 MODULE_PARM_DESC(radio_nr, "Radio Nr");
120 
121 static int usb_amradio_probe(struct usb_interface *intf,
122 			     const struct usb_device_id *id);
123 static void usb_amradio_disconnect(struct usb_interface *intf);
124 static int usb_amradio_open(struct file *file);
125 static int usb_amradio_close(struct file *file);
126 static int usb_amradio_suspend(struct usb_interface *intf,
127 				pm_message_t message);
128 static int usb_amradio_resume(struct usb_interface *intf);
129 
130 /* Data for one (physical) device */
131 struct amradio_device {
132 	/* reference to USB and video device */
133 	struct usb_device *usbdev;
134 	struct usb_interface *intf;
135 	struct video_device videodev;
136 	struct v4l2_device v4l2_dev;
137 
138 	unsigned char *buffer;
139 	struct mutex lock;	/* buffer locking */
140 	int curfreq;
141 	int stereo;
142 	int muted;
143 	int initialized;
144 };
145 
146 static inline struct amradio_device *to_amradio_dev(struct v4l2_device *v4l2_dev)
147 {
148 	return container_of(v4l2_dev, struct amradio_device, v4l2_dev);
149 }
150 
151 /* USB Device ID List */
152 static struct usb_device_id usb_amradio_device_table[] = {
153 	{USB_DEVICE_AND_INTERFACE_INFO(USB_AMRADIO_VENDOR, USB_AMRADIO_PRODUCT,
154 							USB_CLASS_HID, 0, 0) },
155 	{ }						/* Terminating entry */
156 };
157 
158 MODULE_DEVICE_TABLE(usb, usb_amradio_device_table);
159 
160 /* USB subsystem interface */
161 static struct usb_driver usb_amradio_driver = {
162 	.name			= MR800_DRIVER_NAME,
163 	.probe			= usb_amradio_probe,
164 	.disconnect		= usb_amradio_disconnect,
165 	.suspend		= usb_amradio_suspend,
166 	.resume			= usb_amradio_resume,
167 	.reset_resume		= usb_amradio_resume,
168 	.id_table		= usb_amradio_device_table,
169 	.supports_autosuspend	= 1,
170 };
171 
172 /* switch on/off the radio. Send 8 bytes to device */
173 static int amradio_set_mute(struct amradio_device *radio, char argument)
174 {
175 	int retval;
176 	int size;
177 
178 	radio->buffer[0] = 0x00;
179 	radio->buffer[1] = 0x55;
180 	radio->buffer[2] = 0xaa;
181 	radio->buffer[3] = 0x00;
182 	radio->buffer[4] = AMRADIO_SET_MUTE;
183 	radio->buffer[5] = argument;
184 	radio->buffer[6] = 0x00;
185 	radio->buffer[7] = 0x00;
186 
187 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
188 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
189 
190 	if (retval < 0 || size != BUFFER_LENGTH) {
191 		amradio_dev_warn(&radio->videodev.dev, "set mute failed\n");
192 		return retval;
193 	}
194 
195 	radio->muted = argument;
196 
197 	return retval;
198 }
199 
200 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
201 static int amradio_setfreq(struct amradio_device *radio, int freq)
202 {
203 	int retval;
204 	int size;
205 	unsigned short freq_send = 0x10 + (freq >> 3) / 25;
206 
207 	radio->buffer[0] = 0x00;
208 	radio->buffer[1] = 0x55;
209 	radio->buffer[2] = 0xaa;
210 	radio->buffer[3] = 0x03;
211 	radio->buffer[4] = AMRADIO_SET_FREQ;
212 	radio->buffer[5] = 0x00;
213 	radio->buffer[6] = 0x00;
214 	radio->buffer[7] = 0x08;
215 
216 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
217 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
218 
219 	if (retval < 0 || size != BUFFER_LENGTH)
220 		goto out_err;
221 
222 	/* frequency is calculated from freq_send and placed in first 2 bytes */
223 	radio->buffer[0] = (freq_send >> 8) & 0xff;
224 	radio->buffer[1] = freq_send & 0xff;
225 	radio->buffer[2] = 0x01;
226 	radio->buffer[3] = 0x00;
227 	radio->buffer[4] = 0x00;
228 	/* 5 and 6 bytes of buffer already = 0x00 */
229 	radio->buffer[7] = 0x00;
230 
231 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
232 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
233 
234 	if (retval < 0 || size != BUFFER_LENGTH)
235 		goto out_err;
236 
237 	radio->curfreq = freq;
238 	goto out;
239 
240 out_err:
241 	amradio_dev_warn(&radio->videodev.dev, "set frequency failed\n");
242 out:
243 	return retval;
244 }
245 
246 static int amradio_set_stereo(struct amradio_device *radio, char argument)
247 {
248 	int retval;
249 	int size;
250 
251 	radio->buffer[0] = 0x00;
252 	radio->buffer[1] = 0x55;
253 	radio->buffer[2] = 0xaa;
254 	radio->buffer[3] = 0x00;
255 	radio->buffer[4] = AMRADIO_SET_MONO;
256 	radio->buffer[5] = argument;
257 	radio->buffer[6] = 0x00;
258 	radio->buffer[7] = 0x00;
259 
260 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
261 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
262 
263 	if (retval < 0 || size != BUFFER_LENGTH) {
264 		amradio_dev_warn(&radio->videodev.dev, "set stereo failed\n");
265 		return retval;
266 	}
267 
268 	if (argument == WANT_STEREO)
269 		radio->stereo = 1;
270 	else
271 		radio->stereo = 0;
272 
273 	return retval;
274 }
275 
276 /* Handle unplugging the device.
277  * We call video_unregister_device in any case.
278  * The last function called in this procedure is
279  * usb_amradio_device_release.
280  */
281 static void usb_amradio_disconnect(struct usb_interface *intf)
282 {
283 	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
284 
285 	mutex_lock(&radio->lock);
286 	/* increase the device node's refcount */
287 	get_device(&radio->videodev.dev);
288 	v4l2_device_disconnect(&radio->v4l2_dev);
289 	video_unregister_device(&radio->videodev);
290 	mutex_unlock(&radio->lock);
291 	/* decrease the device node's refcount, allowing it to be released */
292 	put_device(&radio->videodev.dev);
293 }
294 
295 /* vidioc_querycap - query device capabilities */
296 static int vidioc_querycap(struct file *file, void *priv,
297 					struct v4l2_capability *v)
298 {
299 	struct amradio_device *radio = file->private_data;
300 
301 	strlcpy(v->driver, "radio-mr800", sizeof(v->driver));
302 	strlcpy(v->card, "AverMedia MR 800 USB FM Radio", sizeof(v->card));
303 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
304 	v->version = RADIO_VERSION;
305 	v->capabilities = V4L2_CAP_TUNER;
306 	return 0;
307 }
308 
309 /* vidioc_g_tuner - get tuner attributes */
310 static int vidioc_g_tuner(struct file *file, void *priv,
311 				struct v4l2_tuner *v)
312 {
313 	struct amradio_device *radio = file->private_data;
314 	int retval;
315 
316 	if (v->index > 0)
317 		return -EINVAL;
318 
319 /* TODO: Add function which look is signal stereo or not
320  * 	amradio_getstat(radio);
321  */
322 
323 /* we call amradio_set_stereo to set radio->stereo
324  * Honestly, amradio_getstat should cover this in future and
325  * amradio_set_stereo shouldn't be here
326  */
327 	retval = amradio_set_stereo(radio, WANT_STEREO);
328 
329 	strcpy(v->name, "FM");
330 	v->type = V4L2_TUNER_RADIO;
331 	v->rangelow = FREQ_MIN * FREQ_MUL;
332 	v->rangehigh = FREQ_MAX * FREQ_MUL;
333 	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
334 	v->capability = V4L2_TUNER_CAP_LOW;
335 	if (radio->stereo)
336 		v->audmode = V4L2_TUNER_MODE_STEREO;
337 	else
338 		v->audmode = V4L2_TUNER_MODE_MONO;
339 	v->signal = 0xffff;     /* Can't get the signal strength, sad.. */
340 	v->afc = 0; /* Don't know what is this */
341 
342 	return retval;
343 }
344 
345 /* vidioc_s_tuner - set tuner attributes */
346 static int vidioc_s_tuner(struct file *file, void *priv,
347 				struct v4l2_tuner *v)
348 {
349 	struct amradio_device *radio = file->private_data;
350 	int retval = -EINVAL;
351 
352 	if (v->index > 0)
353 		return -EINVAL;
354 
355 	/* mono/stereo selector */
356 	switch (v->audmode) {
357 	case V4L2_TUNER_MODE_MONO:
358 		retval = amradio_set_stereo(radio, WANT_MONO);
359 		break;
360 	case V4L2_TUNER_MODE_STEREO:
361 		retval = amradio_set_stereo(radio, WANT_STEREO);
362 		break;
363 	}
364 
365 	return retval;
366 }
367 
368 /* vidioc_s_frequency - set tuner radio frequency */
369 static int vidioc_s_frequency(struct file *file, void *priv,
370 				struct v4l2_frequency *f)
371 {
372 	struct amradio_device *radio = file->private_data;
373 
374 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
375 		return -EINVAL;
376 	return amradio_setfreq(radio, f->frequency);
377 }
378 
379 /* vidioc_g_frequency - get tuner radio frequency */
380 static int vidioc_g_frequency(struct file *file, void *priv,
381 				struct v4l2_frequency *f)
382 {
383 	struct amradio_device *radio = file->private_data;
384 
385 	if (f->tuner != 0)
386 		return -EINVAL;
387 	f->type = V4L2_TUNER_RADIO;
388 	f->frequency = radio->curfreq;
389 
390 	return 0;
391 }
392 
393 /* vidioc_queryctrl - enumerate control items */
394 static int vidioc_queryctrl(struct file *file, void *priv,
395 				struct v4l2_queryctrl *qc)
396 {
397 	switch (qc->id) {
398 	case V4L2_CID_AUDIO_MUTE:
399 		return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
400 	}
401 
402 	return -EINVAL;
403 }
404 
405 /* vidioc_g_ctrl - get the value of a control */
406 static int vidioc_g_ctrl(struct file *file, void *priv,
407 				struct v4l2_control *ctrl)
408 {
409 	struct amradio_device *radio = file->private_data;
410 
411 	switch (ctrl->id) {
412 	case V4L2_CID_AUDIO_MUTE:
413 		ctrl->value = radio->muted;
414 		return 0;
415 	}
416 
417 	return -EINVAL;
418 }
419 
420 /* vidioc_s_ctrl - set the value of a control */
421 static int vidioc_s_ctrl(struct file *file, void *priv,
422 				struct v4l2_control *ctrl)
423 {
424 	struct amradio_device *radio = file->private_data;
425 	int retval = -EINVAL;
426 
427 	switch (ctrl->id) {
428 	case V4L2_CID_AUDIO_MUTE:
429 		if (ctrl->value)
430 			retval = amradio_set_mute(radio, AMRADIO_STOP);
431 		else
432 			retval = amradio_set_mute(radio, AMRADIO_START);
433 
434 		break;
435 	}
436 
437 	return retval;
438 }
439 
440 /* vidioc_g_audio - get audio attributes */
441 static int vidioc_g_audio(struct file *file, void *priv,
442 				struct v4l2_audio *a)
443 {
444 	if (a->index > 1)
445 		return -EINVAL;
446 
447 	strcpy(a->name, "Radio");
448 	a->capability = V4L2_AUDCAP_STEREO;
449 	return 0;
450 }
451 
452 /* vidioc_s_audio - set audio attributes  */
453 static int vidioc_s_audio(struct file *file, void *priv,
454 					struct v4l2_audio *a)
455 {
456 	if (a->index != 0)
457 		return -EINVAL;
458 	return 0;
459 }
460 
461 /* vidioc_g_input - get input */
462 static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
463 {
464 	*i = 0;
465 	return 0;
466 }
467 
468 /* vidioc_s_input - set input */
469 static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
470 {
471 	if (i != 0)
472 		return -EINVAL;
473 	return 0;
474 }
475 
476 static int usb_amradio_init(struct amradio_device *radio)
477 {
478 	int retval;
479 
480 	retval = amradio_set_mute(radio, AMRADIO_STOP);
481 	if (retval)
482 		goto out_err;
483 
484 	retval = amradio_set_stereo(radio, WANT_STEREO);
485 	if (retval)
486 		goto out_err;
487 
488 	radio->initialized = 1;
489 	goto out;
490 
491 out_err:
492 	amradio_dev_err(&radio->videodev.dev, "initialization failed\n");
493 out:
494 	return retval;
495 }
496 
497 /* open device - amradio_start() and amradio_setfreq() */
498 static int usb_amradio_open(struct file *file)
499 {
500 	struct amradio_device *radio = video_drvdata(file);
501 	int retval;
502 
503 	file->private_data = radio;
504 	retval = usb_autopm_get_interface(radio->intf);
505 	if (retval)
506 		return retval;
507 
508 	if (unlikely(!radio->initialized)) {
509 		retval = usb_amradio_init(radio);
510 		if (retval)
511 			usb_autopm_put_interface(radio->intf);
512 	}
513 	return retval;
514 }
515 
516 /*close device */
517 static int usb_amradio_close(struct file *file)
518 {
519 	struct amradio_device *radio = file->private_data;
520 
521 	if (video_is_registered(&radio->videodev))
522 		usb_autopm_put_interface(radio->intf);
523 	return 0;
524 }
525 
526 /* Suspend device - stop device. Need to be checked and fixed */
527 static int usb_amradio_suspend(struct usb_interface *intf, pm_message_t message)
528 {
529 	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
530 
531 	mutex_lock(&radio->lock);
532 	if (!radio->muted && radio->initialized) {
533 		amradio_set_mute(radio, AMRADIO_STOP);
534 		radio->muted = 0;
535 	}
536 	mutex_unlock(&radio->lock);
537 
538 	dev_info(&intf->dev, "going into suspend..\n");
539 	return 0;
540 }
541 
542 /* Resume device - start device. Need to be checked and fixed */
543 static int usb_amradio_resume(struct usb_interface *intf)
544 {
545 	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
546 
547 	mutex_lock(&radio->lock);
548 	if (unlikely(!radio->initialized))
549 		goto unlock;
550 
551 	if (radio->stereo)
552 		amradio_set_stereo(radio, WANT_STEREO);
553 	else
554 		amradio_set_stereo(radio, WANT_MONO);
555 
556 	amradio_setfreq(radio, radio->curfreq);
557 
558 	if (!radio->muted)
559 		amradio_set_mute(radio, AMRADIO_START);
560 
561 unlock:
562 	mutex_unlock(&radio->lock);
563 
564 	dev_info(&intf->dev, "coming out of suspend..\n");
565 	return 0;
566 }
567 
568 /* File system interface */
569 static const struct v4l2_file_operations usb_amradio_fops = {
570 	.owner		= THIS_MODULE,
571 	.open		= usb_amradio_open,
572 	.release	= usb_amradio_close,
573 	.unlocked_ioctl	= video_ioctl2,
574 };
575 
576 static const struct v4l2_ioctl_ops usb_amradio_ioctl_ops = {
577 	.vidioc_querycap    = vidioc_querycap,
578 	.vidioc_g_tuner     = vidioc_g_tuner,
579 	.vidioc_s_tuner     = vidioc_s_tuner,
580 	.vidioc_g_frequency = vidioc_g_frequency,
581 	.vidioc_s_frequency = vidioc_s_frequency,
582 	.vidioc_queryctrl   = vidioc_queryctrl,
583 	.vidioc_g_ctrl      = vidioc_g_ctrl,
584 	.vidioc_s_ctrl      = vidioc_s_ctrl,
585 	.vidioc_g_audio     = vidioc_g_audio,
586 	.vidioc_s_audio     = vidioc_s_audio,
587 	.vidioc_g_input     = vidioc_g_input,
588 	.vidioc_s_input     = vidioc_s_input,
589 };
590 
591 static void usb_amradio_video_device_release(struct video_device *videodev)
592 {
593 	struct amradio_device *radio = video_get_drvdata(videodev);
594 
595 	/* free rest memory */
596 	kfree(radio->buffer);
597 	kfree(radio);
598 }
599 
600 /* check if the device is present and register with v4l and usb if it is */
601 static int usb_amradio_probe(struct usb_interface *intf,
602 				const struct usb_device_id *id)
603 {
604 	struct amradio_device *radio;
605 	int retval = 0;
606 
607 	radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);
608 
609 	if (!radio) {
610 		dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
611 		retval = -ENOMEM;
612 		goto err;
613 	}
614 
615 	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
616 
617 	if (!radio->buffer) {
618 		dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
619 		retval = -ENOMEM;
620 		goto err_nobuf;
621 	}
622 
623 	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
624 	if (retval < 0) {
625 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
626 		goto err_v4l2;
627 	}
628 
629 	mutex_init(&radio->lock);
630 
631 	strlcpy(radio->videodev.name, radio->v4l2_dev.name,
632 		sizeof(radio->videodev.name));
633 	radio->videodev.v4l2_dev = &radio->v4l2_dev;
634 	radio->videodev.fops = &usb_amradio_fops;
635 	radio->videodev.ioctl_ops = &usb_amradio_ioctl_ops;
636 	radio->videodev.release = usb_amradio_video_device_release;
637 	radio->videodev.lock = &radio->lock;
638 
639 	radio->usbdev = interface_to_usbdev(intf);
640 	radio->intf = intf;
641 	radio->curfreq = 95.16 * FREQ_MUL;
642 
643 	video_set_drvdata(&radio->videodev, radio);
644 
645 	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO,
646 					radio_nr);
647 	if (retval < 0) {
648 		dev_err(&intf->dev, "could not register video device\n");
649 		goto err_vdev;
650 	}
651 
652 	return 0;
653 
654 err_vdev:
655 	v4l2_device_unregister(&radio->v4l2_dev);
656 err_v4l2:
657 	kfree(radio->buffer);
658 err_nobuf:
659 	kfree(radio);
660 err:
661 	return retval;
662 }
663 
664 static int __init amradio_init(void)
665 {
666 	int retval = usb_register(&usb_amradio_driver);
667 
668 	pr_info(KBUILD_MODNAME
669 		": version " DRIVER_VERSION " " DRIVER_DESC "\n");
670 
671 	if (retval)
672 		pr_err(KBUILD_MODNAME
673 			": usb_register failed. Error number %d\n", retval);
674 
675 	return retval;
676 }
677 
678 static void __exit amradio_exit(void)
679 {
680 	usb_deregister(&usb_amradio_driver);
681 }
682 
683 module_init(amradio_init);
684 module_exit(amradio_exit);
685 
686