xref: /linux/drivers/media/usb/cx231xx/cx231xx-audio.c (revision 3d0fe49454652117522f60bfbefb978ba0e5300b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Conexant Cx231xx audio extension
4  *
5  *  Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
6  *       Based on em28xx driver
7  */
8 
9 #include "cx231xx.h"
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/sound.h>
13 #include <linux/spinlock.h>
14 #include <linux/soundcard.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <sound/core.h>
18 #include <sound/pcm.h>
19 #include <sound/pcm_params.h>
20 #include <sound/info.h>
21 #include <sound/initval.h>
22 #include <sound/control.h>
23 #include <media/v4l2-common.h>
24 
25 static int debug;
26 module_param(debug, int, 0644);
27 MODULE_PARM_DESC(debug, "activates debug info");
28 
29 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
30 
31 static int cx231xx_isoc_audio_deinit(struct cx231xx *dev)
32 {
33 	int i;
34 
35 	dev_dbg(dev->dev, "Stopping isoc\n");
36 
37 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
38 		if (dev->adev.urb[i]) {
39 			if (!irqs_disabled())
40 				usb_kill_urb(dev->adev.urb[i]);
41 			else
42 				usb_unlink_urb(dev->adev.urb[i]);
43 
44 			usb_free_urb(dev->adev.urb[i]);
45 			dev->adev.urb[i] = NULL;
46 
47 			kfree(dev->adev.transfer_buffer[i]);
48 			dev->adev.transfer_buffer[i] = NULL;
49 		}
50 	}
51 
52 	return 0;
53 }
54 
55 static int cx231xx_bulk_audio_deinit(struct cx231xx *dev)
56 {
57 	int i;
58 
59 	dev_dbg(dev->dev, "Stopping bulk\n");
60 
61 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
62 		if (dev->adev.urb[i]) {
63 			if (!irqs_disabled())
64 				usb_kill_urb(dev->adev.urb[i]);
65 			else
66 				usb_unlink_urb(dev->adev.urb[i]);
67 
68 			usb_free_urb(dev->adev.urb[i]);
69 			dev->adev.urb[i] = NULL;
70 
71 			kfree(dev->adev.transfer_buffer[i]);
72 			dev->adev.transfer_buffer[i] = NULL;
73 		}
74 	}
75 
76 	return 0;
77 }
78 
79 static void cx231xx_audio_isocirq(struct urb *urb)
80 {
81 	struct cx231xx *dev = urb->context;
82 	int i;
83 	unsigned int oldptr;
84 	int period_elapsed = 0;
85 	int status;
86 	unsigned char *cp;
87 	unsigned int stride;
88 	struct snd_pcm_substream *substream;
89 	struct snd_pcm_runtime *runtime;
90 
91 	if (dev->state & DEV_DISCONNECTED)
92 		return;
93 
94 	switch (urb->status) {
95 	case 0:		/* success */
96 	case -ETIMEDOUT:	/* NAK */
97 		break;
98 	case -ECONNRESET:	/* kill */
99 	case -ENOENT:
100 	case -ESHUTDOWN:
101 		return;
102 	default:		/* error */
103 		dev_dbg(dev->dev, "urb completion error %d.\n",
104 			urb->status);
105 		break;
106 	}
107 
108 	if (atomic_read(&dev->stream_started) == 0)
109 		return;
110 
111 	if (dev->adev.capture_pcm_substream) {
112 		substream = dev->adev.capture_pcm_substream;
113 		runtime = substream->runtime;
114 		stride = runtime->frame_bits >> 3;
115 
116 		for (i = 0; i < urb->number_of_packets; i++) {
117 			unsigned long flags;
118 			int length = urb->iso_frame_desc[i].actual_length /
119 				     stride;
120 			cp = (unsigned char *)urb->transfer_buffer +
121 					      urb->iso_frame_desc[i].offset;
122 
123 			if (!length)
124 				continue;
125 
126 			oldptr = dev->adev.hwptr_done_capture;
127 			if (oldptr + length >= runtime->buffer_size) {
128 				unsigned int cnt;
129 
130 				cnt = runtime->buffer_size - oldptr;
131 				memcpy(runtime->dma_area + oldptr * stride, cp,
132 				       cnt * stride);
133 				memcpy(runtime->dma_area, cp + cnt * stride,
134 				       length * stride - cnt * stride);
135 			} else {
136 				memcpy(runtime->dma_area + oldptr * stride, cp,
137 				       length * stride);
138 			}
139 
140 			snd_pcm_stream_lock_irqsave(substream, flags);
141 
142 			dev->adev.hwptr_done_capture += length;
143 			if (dev->adev.hwptr_done_capture >=
144 						runtime->buffer_size)
145 				dev->adev.hwptr_done_capture -=
146 						runtime->buffer_size;
147 
148 			dev->adev.capture_transfer_done += length;
149 			if (dev->adev.capture_transfer_done >=
150 				runtime->period_size) {
151 				dev->adev.capture_transfer_done -=
152 						runtime->period_size;
153 				period_elapsed = 1;
154 			}
155 			snd_pcm_stream_unlock_irqrestore(substream, flags);
156 		}
157 		if (period_elapsed)
158 			snd_pcm_period_elapsed(substream);
159 	}
160 	urb->status = 0;
161 
162 	status = usb_submit_urb(urb, GFP_ATOMIC);
163 	if (status < 0) {
164 		dev_err(dev->dev,
165 			"resubmit of audio urb failed (error=%i)\n",
166 			status);
167 	}
168 	return;
169 }
170 
171 static void cx231xx_audio_bulkirq(struct urb *urb)
172 {
173 	struct cx231xx *dev = urb->context;
174 	unsigned int oldptr;
175 	int period_elapsed = 0;
176 	int status;
177 	unsigned char *cp;
178 	unsigned int stride;
179 	struct snd_pcm_substream *substream;
180 	struct snd_pcm_runtime *runtime;
181 
182 	if (dev->state & DEV_DISCONNECTED)
183 		return;
184 
185 	switch (urb->status) {
186 	case 0:		/* success */
187 	case -ETIMEDOUT:	/* NAK */
188 		break;
189 	case -ECONNRESET:	/* kill */
190 	case -ENOENT:
191 	case -ESHUTDOWN:
192 		return;
193 	default:		/* error */
194 		dev_dbg(dev->dev, "urb completion error %d.\n",
195 			urb->status);
196 		break;
197 	}
198 
199 	if (atomic_read(&dev->stream_started) == 0)
200 		return;
201 
202 	if (dev->adev.capture_pcm_substream) {
203 		substream = dev->adev.capture_pcm_substream;
204 		runtime = substream->runtime;
205 		stride = runtime->frame_bits >> 3;
206 
207 		if (1) {
208 			unsigned long flags;
209 			int length = urb->actual_length /
210 				     stride;
211 			cp = (unsigned char *)urb->transfer_buffer;
212 
213 			oldptr = dev->adev.hwptr_done_capture;
214 			if (oldptr + length >= runtime->buffer_size) {
215 				unsigned int cnt;
216 
217 				cnt = runtime->buffer_size - oldptr;
218 				memcpy(runtime->dma_area + oldptr * stride, cp,
219 				       cnt * stride);
220 				memcpy(runtime->dma_area, cp + cnt * stride,
221 				       length * stride - cnt * stride);
222 			} else {
223 				memcpy(runtime->dma_area + oldptr * stride, cp,
224 				       length * stride);
225 			}
226 
227 			snd_pcm_stream_lock_irqsave(substream, flags);
228 
229 			dev->adev.hwptr_done_capture += length;
230 			if (dev->adev.hwptr_done_capture >=
231 						runtime->buffer_size)
232 				dev->adev.hwptr_done_capture -=
233 						runtime->buffer_size;
234 
235 			dev->adev.capture_transfer_done += length;
236 			if (dev->adev.capture_transfer_done >=
237 				runtime->period_size) {
238 				dev->adev.capture_transfer_done -=
239 						runtime->period_size;
240 				period_elapsed = 1;
241 			}
242 			snd_pcm_stream_unlock_irqrestore(substream, flags);
243 		}
244 		if (period_elapsed)
245 			snd_pcm_period_elapsed(substream);
246 	}
247 	urb->status = 0;
248 
249 	status = usb_submit_urb(urb, GFP_ATOMIC);
250 	if (status < 0) {
251 		dev_err(dev->dev,
252 			"resubmit of audio urb failed (error=%i)\n",
253 			status);
254 	}
255 	return;
256 }
257 
258 static int cx231xx_init_audio_isoc(struct cx231xx *dev)
259 {
260 	int i, errCode;
261 	int sb_size;
262 
263 	dev_dbg(dev->dev,
264 		"%s: Starting ISO AUDIO transfers\n", __func__);
265 
266 	if (dev->state & DEV_DISCONNECTED)
267 		return -ENODEV;
268 
269 	sb_size = CX231XX_ISO_NUM_AUDIO_PACKETS * dev->adev.max_pkt_size;
270 
271 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
272 		struct urb *urb;
273 		int j, k;
274 
275 		dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
276 		if (!dev->adev.transfer_buffer[i])
277 			return -ENOMEM;
278 
279 		memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
280 		urb = usb_alloc_urb(CX231XX_ISO_NUM_AUDIO_PACKETS, GFP_ATOMIC);
281 		if (!urb) {
282 			for (j = 0; j < i; j++) {
283 				usb_free_urb(dev->adev.urb[j]);
284 				kfree(dev->adev.transfer_buffer[j]);
285 			}
286 			return -ENOMEM;
287 		}
288 
289 		urb->dev = dev->udev;
290 		urb->context = dev;
291 		urb->pipe = usb_rcvisocpipe(dev->udev,
292 						dev->adev.end_point_addr);
293 		urb->transfer_flags = URB_ISO_ASAP;
294 		urb->transfer_buffer = dev->adev.transfer_buffer[i];
295 		urb->interval = 1;
296 		urb->complete = cx231xx_audio_isocirq;
297 		urb->number_of_packets = CX231XX_ISO_NUM_AUDIO_PACKETS;
298 		urb->transfer_buffer_length = sb_size;
299 
300 		for (j = k = 0; j < CX231XX_ISO_NUM_AUDIO_PACKETS;
301 			j++, k += dev->adev.max_pkt_size) {
302 			urb->iso_frame_desc[j].offset = k;
303 			urb->iso_frame_desc[j].length = dev->adev.max_pkt_size;
304 		}
305 		dev->adev.urb[i] = urb;
306 	}
307 
308 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
309 		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
310 		if (errCode < 0) {
311 			cx231xx_isoc_audio_deinit(dev);
312 			return errCode;
313 		}
314 	}
315 
316 	return errCode;
317 }
318 
319 static int cx231xx_init_audio_bulk(struct cx231xx *dev)
320 {
321 	int i, errCode;
322 	int sb_size;
323 
324 	dev_dbg(dev->dev,
325 		"%s: Starting BULK AUDIO transfers\n", __func__);
326 
327 	if (dev->state & DEV_DISCONNECTED)
328 		return -ENODEV;
329 
330 	sb_size = CX231XX_NUM_AUDIO_PACKETS * dev->adev.max_pkt_size;
331 
332 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
333 		struct urb *urb;
334 		int j;
335 
336 		dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
337 		if (!dev->adev.transfer_buffer[i])
338 			return -ENOMEM;
339 
340 		memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
341 		urb = usb_alloc_urb(CX231XX_NUM_AUDIO_PACKETS, GFP_ATOMIC);
342 		if (!urb) {
343 			for (j = 0; j < i; j++) {
344 				usb_free_urb(dev->adev.urb[j]);
345 				kfree(dev->adev.transfer_buffer[j]);
346 			}
347 			return -ENOMEM;
348 		}
349 
350 		urb->dev = dev->udev;
351 		urb->context = dev;
352 		urb->pipe = usb_rcvbulkpipe(dev->udev,
353 						dev->adev.end_point_addr);
354 		urb->transfer_flags = 0;
355 		urb->transfer_buffer = dev->adev.transfer_buffer[i];
356 		urb->complete = cx231xx_audio_bulkirq;
357 		urb->transfer_buffer_length = sb_size;
358 
359 		dev->adev.urb[i] = urb;
360 
361 	}
362 
363 	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
364 		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
365 		if (errCode < 0) {
366 			cx231xx_bulk_audio_deinit(dev);
367 			return errCode;
368 		}
369 	}
370 
371 	return errCode;
372 }
373 
374 static const struct snd_pcm_hardware snd_cx231xx_hw_capture = {
375 	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER	|
376 	    SNDRV_PCM_INFO_MMAP			|
377 	    SNDRV_PCM_INFO_INTERLEAVED		|
378 	    SNDRV_PCM_INFO_MMAP_VALID,
379 
380 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
381 
382 	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_KNOT,
383 
384 	.rate_min = 48000,
385 	.rate_max = 48000,
386 	.channels_min = 2,
387 	.channels_max = 2,
388 	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
389 	.period_bytes_min = 64,		/* 12544/2, */
390 	.period_bytes_max = 12544,
391 	.periods_min = 2,
392 	.periods_max = 98,		/* 12544, */
393 };
394 
395 static int snd_cx231xx_capture_open(struct snd_pcm_substream *substream)
396 {
397 	struct cx231xx *dev = snd_pcm_substream_chip(substream);
398 	struct snd_pcm_runtime *runtime = substream->runtime;
399 	int ret = 0;
400 
401 	dev_dbg(dev->dev,
402 		"opening device and trying to acquire exclusive lock\n");
403 
404 	if (dev->state & DEV_DISCONNECTED) {
405 		dev_err(dev->dev,
406 			"Can't open. the device was removed.\n");
407 		return -ENODEV;
408 	}
409 
410 	/* set alternate setting for audio interface */
411 	/* 1 - 48000 samples per sec */
412 	mutex_lock(&dev->lock);
413 	if (dev->USE_ISO)
414 		ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 1);
415 	else
416 		ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 0);
417 	mutex_unlock(&dev->lock);
418 	if (ret < 0) {
419 		dev_err(dev->dev,
420 			"failed to set alternate setting !\n");
421 
422 		return ret;
423 	}
424 
425 	runtime->hw = snd_cx231xx_hw_capture;
426 
427 	mutex_lock(&dev->lock);
428 	/* inform hardware to start streaming */
429 	ret = cx231xx_capture_start(dev, 1, Audio);
430 
431 	dev->adev.users++;
432 	mutex_unlock(&dev->lock);
433 
434 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
435 	dev->adev.capture_pcm_substream = substream;
436 	runtime->private_data = dev;
437 
438 	return 0;
439 }
440 
441 static int snd_cx231xx_pcm_close(struct snd_pcm_substream *substream)
442 {
443 	int ret;
444 	struct cx231xx *dev = snd_pcm_substream_chip(substream);
445 
446 	dev_dbg(dev->dev, "closing device\n");
447 
448 	/* inform hardware to stop streaming */
449 	mutex_lock(&dev->lock);
450 	ret = cx231xx_capture_start(dev, 0, Audio);
451 
452 	/* set alternate setting for audio interface */
453 	/* 1 - 48000 samples per sec */
454 	ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 0);
455 	if (ret < 0) {
456 		dev_err(dev->dev,
457 			"failed to set alternate setting !\n");
458 
459 		mutex_unlock(&dev->lock);
460 		return ret;
461 	}
462 
463 	dev->adev.users--;
464 	mutex_unlock(&dev->lock);
465 
466 	if (dev->adev.users == 0 && dev->adev.shutdown == 1) {
467 		dev_dbg(dev->dev, "audio users: %d\n", dev->adev.users);
468 		dev_dbg(dev->dev, "disabling audio stream!\n");
469 		dev->adev.shutdown = 0;
470 		dev_dbg(dev->dev, "released lock\n");
471 		if (atomic_read(&dev->stream_started) > 0) {
472 			atomic_set(&dev->stream_started, 0);
473 			schedule_work(&dev->wq_trigger);
474 		}
475 	}
476 	return 0;
477 }
478 
479 static int snd_cx231xx_prepare(struct snd_pcm_substream *substream)
480 {
481 	struct cx231xx *dev = snd_pcm_substream_chip(substream);
482 
483 	dev->adev.hwptr_done_capture = 0;
484 	dev->adev.capture_transfer_done = 0;
485 
486 	return 0;
487 }
488 
489 static void audio_trigger(struct work_struct *work)
490 {
491 	struct cx231xx *dev = container_of(work, struct cx231xx, wq_trigger);
492 
493 	if (atomic_read(&dev->stream_started)) {
494 		dev_dbg(dev->dev, "starting capture");
495 		if (is_fw_load(dev) == 0)
496 			cx25840_call(dev, core, load_fw);
497 		if (dev->USE_ISO)
498 			cx231xx_init_audio_isoc(dev);
499 		else
500 			cx231xx_init_audio_bulk(dev);
501 	} else {
502 		dev_dbg(dev->dev, "stopping capture");
503 		cx231xx_isoc_audio_deinit(dev);
504 	}
505 }
506 
507 static int snd_cx231xx_capture_trigger(struct snd_pcm_substream *substream,
508 				       int cmd)
509 {
510 	struct cx231xx *dev = snd_pcm_substream_chip(substream);
511 	int retval = 0;
512 
513 	if (dev->state & DEV_DISCONNECTED)
514 		return -ENODEV;
515 
516 	spin_lock(&dev->adev.slock);
517 	switch (cmd) {
518 	case SNDRV_PCM_TRIGGER_START:
519 		atomic_set(&dev->stream_started, 1);
520 		break;
521 	case SNDRV_PCM_TRIGGER_STOP:
522 		atomic_set(&dev->stream_started, 0);
523 		break;
524 	default:
525 		retval = -EINVAL;
526 		break;
527 	}
528 	spin_unlock(&dev->adev.slock);
529 
530 	schedule_work(&dev->wq_trigger);
531 
532 	return retval;
533 }
534 
535 static snd_pcm_uframes_t snd_cx231xx_capture_pointer(struct snd_pcm_substream
536 						     *substream)
537 {
538 	struct cx231xx *dev;
539 	unsigned long flags;
540 	snd_pcm_uframes_t hwptr_done;
541 
542 	dev = snd_pcm_substream_chip(substream);
543 
544 	spin_lock_irqsave(&dev->adev.slock, flags);
545 	hwptr_done = dev->adev.hwptr_done_capture;
546 	spin_unlock_irqrestore(&dev->adev.slock, flags);
547 
548 	return hwptr_done;
549 }
550 
551 static const struct snd_pcm_ops snd_cx231xx_pcm_capture = {
552 	.open = snd_cx231xx_capture_open,
553 	.close = snd_cx231xx_pcm_close,
554 	.prepare = snd_cx231xx_prepare,
555 	.trigger = snd_cx231xx_capture_trigger,
556 	.pointer = snd_cx231xx_capture_pointer,
557 };
558 
559 static int cx231xx_audio_init(struct cx231xx *dev)
560 {
561 	struct cx231xx_audio *adev = &dev->adev;
562 	struct snd_pcm *pcm;
563 	struct snd_card *card;
564 	static int devnr;
565 	int err;
566 	struct usb_interface *uif;
567 	int i, isoc_pipe = 0;
568 
569 	if (dev->has_alsa_audio != 1) {
570 		/* This device does not support the extension (in this case
571 		   the device is expecting the snd-usb-audio module or
572 		   doesn't have analog audio support at all) */
573 		return 0;
574 	}
575 
576 	dev_dbg(dev->dev,
577 		"probing for cx231xx non standard usbaudio\n");
578 
579 	err = snd_card_new(dev->dev, index[devnr], "Cx231xx Audio",
580 			   THIS_MODULE, 0, &card);
581 	if (err < 0)
582 		return err;
583 
584 	spin_lock_init(&adev->slock);
585 	err = snd_pcm_new(card, "Cx231xx Audio", 0, 0, 1, &pcm);
586 	if (err < 0)
587 		goto err_free_card;
588 
589 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
590 			&snd_cx231xx_pcm_capture);
591 	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
592 	pcm->info_flags = 0;
593 	pcm->private_data = dev;
594 	strscpy(pcm->name, "Conexant cx231xx Capture", sizeof(pcm->name));
595 	strscpy(card->driver, "Cx231xx-Audio", sizeof(card->driver));
596 	strscpy(card->shortname, "Cx231xx Audio", sizeof(card->shortname));
597 	strscpy(card->longname, "Conexant cx231xx Audio", sizeof(card->longname));
598 
599 	INIT_WORK(&dev->wq_trigger, audio_trigger);
600 
601 	err = snd_card_register(card);
602 	if (err < 0)
603 		goto err_free_card;
604 
605 	adev->sndcard = card;
606 	adev->udev = dev->udev;
607 
608 	/* compute alternate max packet sizes for Audio */
609 	uif =
610 	    dev->udev->actconfig->interface[dev->current_pcb_config.
611 					    hs_config_info[0].interface_info.
612 					    audio_index + 1];
613 
614 	if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1) {
615 		err = -ENODEV;
616 		goto err_free_card;
617 	}
618 
619 	adev->end_point_addr =
620 	    uif->altsetting[0].endpoint[isoc_pipe].desc.
621 			bEndpointAddress;
622 
623 	adev->num_alt = uif->num_altsetting;
624 	dev_info(dev->dev,
625 		"audio EndPoint Addr 0x%x, Alternate settings: %i\n",
626 		adev->end_point_addr, adev->num_alt);
627 	adev->alt_max_pkt_size = kmalloc_array(32, adev->num_alt, GFP_KERNEL);
628 	if (!adev->alt_max_pkt_size) {
629 		err = -ENOMEM;
630 		goto err_free_card;
631 	}
632 
633 	for (i = 0; i < adev->num_alt; i++) {
634 		u16 tmp;
635 
636 		if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1) {
637 			err = -ENODEV;
638 			goto err_free_pkt_size;
639 		}
640 
641 		tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.
642 				wMaxPacketSize);
643 		adev->alt_max_pkt_size[i] =
644 		    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);
645 		dev_dbg(dev->dev,
646 			"audio alternate setting %i, max size= %i\n", i,
647 			adev->alt_max_pkt_size[i]);
648 	}
649 
650 	return 0;
651 
652 err_free_pkt_size:
653 	kfree(adev->alt_max_pkt_size);
654 err_free_card:
655 	snd_card_free(card);
656 
657 	return err;
658 }
659 
660 static int cx231xx_audio_fini(struct cx231xx *dev)
661 {
662 	if (dev == NULL)
663 		return 0;
664 
665 	if (dev->has_alsa_audio != 1) {
666 		/* This device does not support the extension (in this case
667 		   the device is expecting the snd-usb-audio module or
668 		   doesn't have analog audio support at all) */
669 		return 0;
670 	}
671 
672 	if (dev->adev.sndcard) {
673 		snd_card_free_when_closed(dev->adev.sndcard);
674 		kfree(dev->adev.alt_max_pkt_size);
675 		dev->adev.sndcard = NULL;
676 	}
677 
678 	return 0;
679 }
680 
681 static struct cx231xx_ops audio_ops = {
682 	.id = CX231XX_AUDIO,
683 	.name = "Cx231xx Audio Extension",
684 	.init = cx231xx_audio_init,
685 	.fini = cx231xx_audio_fini,
686 };
687 
688 static int __init cx231xx_alsa_register(void)
689 {
690 	return cx231xx_register_extension(&audio_ops);
691 }
692 
693 static void __exit cx231xx_alsa_unregister(void)
694 {
695 	cx231xx_unregister_extension(&audio_ops);
696 }
697 
698 MODULE_LICENSE("GPL");
699 MODULE_AUTHOR("Srinivasa Deevi <srinivasa.deevi@conexant.com>");
700 MODULE_DESCRIPTION("Cx231xx Audio driver");
701 
702 module_init(cx231xx_alsa_register);
703 module_exit(cx231xx_alsa_unregister);
704