Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
em28xx-audio.c
Go to the documentation of this file.
1 /*
2  * Empiatech em28x1 audio extension
3  *
4  * Copyright (C) 2006 Markus Rechberger <[email protected]>
5  *
6  * Copyright (C) 2007-2011 Mauro Carvalho Chehab <[email protected]>
7  * - Port to work with the in-kernel driver
8  * - Cleanups, fixes, alsa-controls, etc.
9  *
10  * This driver is based on my previous au600 usb pstn audio driver
11  * and inherits all the copyrights
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or
16  * (at your option) any later version.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21  * GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with this program; if not, write to the Free Software
25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26  */
27 
28 #include <linux/kernel.h>
29 #include <linux/usb.h>
30 #include <linux/init.h>
31 #include <linux/sound.h>
32 #include <linux/spinlock.h>
33 #include <linux/soundcard.h>
34 #include <linux/slab.h>
35 #include <linux/vmalloc.h>
36 #include <linux/proc_fs.h>
37 #include <linux/module.h>
38 #include <sound/core.h>
39 #include <sound/pcm.h>
40 #include <sound/pcm_params.h>
41 #include <sound/info.h>
42 #include <sound/initval.h>
43 #include <sound/control.h>
44 #include <sound/tlv.h>
45 #include <sound/ac97_codec.h>
46 #include <media/v4l2-common.h>
47 #include "em28xx.h"
48 
49 static int debug;
50 module_param(debug, int, 0644);
51 MODULE_PARM_DESC(debug, "activates debug info");
52 
53 #define dprintk(fmt, arg...) do { \
54  if (debug) \
55  printk(KERN_INFO "em28xx-audio %s: " fmt, \
56  __func__, ##arg); \
57  } while (0)
58 
59 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
60 
61 static int em28xx_deinit_isoc_audio(struct em28xx *dev)
62 {
63  int i;
64 
65  dprintk("Stopping isoc\n");
66  for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
67  if (!irqs_disabled())
68  usb_kill_urb(dev->adev.urb[i]);
69  else
70  usb_unlink_urb(dev->adev.urb[i]);
71 
72  usb_free_urb(dev->adev.urb[i]);
73  dev->adev.urb[i] = NULL;
74 
75  kfree(dev->adev.transfer_buffer[i]);
76  dev->adev.transfer_buffer[i] = NULL;
77  }
78 
79  return 0;
80 }
81 
82 static void em28xx_audio_isocirq(struct urb *urb)
83 {
84  struct em28xx *dev = urb->context;
85  int i;
86  unsigned int oldptr;
87  int period_elapsed = 0;
88  int status;
89  unsigned char *cp;
90  unsigned int stride;
91  struct snd_pcm_substream *substream;
92  struct snd_pcm_runtime *runtime;
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  dprintk("urb completition error %d.\n", urb->status);
104  break;
105  }
106 
107  if (atomic_read(&dev->stream_started) == 0)
108  return;
109 
110  if (dev->adev.capture_pcm_substream) {
111  substream = dev->adev.capture_pcm_substream;
112  runtime = substream->runtime;
113  stride = runtime->frame_bits >> 3;
114 
115  for (i = 0; i < urb->number_of_packets; i++) {
116  int length =
117  urb->iso_frame_desc[i].actual_length / stride;
118  cp = (unsigned char *)urb->transfer_buffer +
119  urb->iso_frame_desc[i].offset;
120 
121  if (!length)
122  continue;
123 
124  oldptr = dev->adev.hwptr_done_capture;
125  if (oldptr + length >= runtime->buffer_size) {
126  unsigned int cnt =
127  runtime->buffer_size - oldptr;
128  memcpy(runtime->dma_area + oldptr * stride, cp,
129  cnt * stride);
130  memcpy(runtime->dma_area, cp + cnt * stride,
131  length * stride - cnt * stride);
132  } else {
133  memcpy(runtime->dma_area + oldptr * stride, cp,
134  length * stride);
135  }
136 
137  snd_pcm_stream_lock(substream);
138 
139  dev->adev.hwptr_done_capture += length;
140  if (dev->adev.hwptr_done_capture >=
141  runtime->buffer_size)
142  dev->adev.hwptr_done_capture -=
143  runtime->buffer_size;
144 
145  dev->adev.capture_transfer_done += length;
146  if (dev->adev.capture_transfer_done >=
147  runtime->period_size) {
148  dev->adev.capture_transfer_done -=
149  runtime->period_size;
150  period_elapsed = 1;
151  }
152 
153  snd_pcm_stream_unlock(substream);
154  }
155  if (period_elapsed)
156  snd_pcm_period_elapsed(substream);
157  }
158  urb->status = 0;
159 
160  status = usb_submit_urb(urb, GFP_ATOMIC);
161  if (status < 0) {
162  em28xx_errdev("resubmit of audio urb failed (error=%i)\n",
163  status);
164  }
165  return;
166 }
167 
168 static int em28xx_init_audio_isoc(struct em28xx *dev)
169 {
170  int i, errCode;
171  const int sb_size = EM28XX_NUM_AUDIO_PACKETS *
173 
174  dprintk("Starting isoc transfers\n");
175 
176  for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
177  struct urb *urb;
178  int j, k;
179 
180  dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
181  if (!dev->adev.transfer_buffer[i])
182  return -ENOMEM;
183 
184  memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
186  if (!urb) {
187  em28xx_errdev("usb_alloc_urb failed!\n");
188  for (j = 0; j < i; j++) {
189  usb_free_urb(dev->adev.urb[j]);
190  kfree(dev->adev.transfer_buffer[j]);
191  }
192  return -ENOMEM;
193  }
194 
195  urb->dev = dev->udev;
196  urb->context = dev;
197  urb->pipe = usb_rcvisocpipe(dev->udev, EM28XX_EP_AUDIO);
198  urb->transfer_flags = URB_ISO_ASAP;
199  urb->transfer_buffer = dev->adev.transfer_buffer[i];
200  urb->interval = 1;
201  urb->complete = em28xx_audio_isocirq;
202  urb->number_of_packets = EM28XX_NUM_AUDIO_PACKETS;
203  urb->transfer_buffer_length = sb_size;
204 
205  for (j = k = 0; j < EM28XX_NUM_AUDIO_PACKETS;
206  j++, k += EM28XX_AUDIO_MAX_PACKET_SIZE) {
207  urb->iso_frame_desc[j].offset = k;
208  urb->iso_frame_desc[j].length =
210  }
211  dev->adev.urb[i] = urb;
212  }
213 
214  for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
215  errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
216  if (errCode) {
217  em28xx_errdev("submit of audio urb failed\n");
218  em28xx_deinit_isoc_audio(dev);
219  atomic_set(&dev->stream_started, 0);
220  return errCode;
221  }
222 
223  }
224 
225  return 0;
226 }
227 
228 static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,
229  size_t size)
230 {
231  struct snd_pcm_runtime *runtime = subs->runtime;
232 
233  dprintk("Allocating vbuffer\n");
234  if (runtime->dma_area) {
235  if (runtime->dma_bytes > size)
236  return 0;
237 
238  vfree(runtime->dma_area);
239  }
240  runtime->dma_area = vmalloc(size);
241  if (!runtime->dma_area)
242  return -ENOMEM;
243 
244  runtime->dma_bytes = size;
245 
246  return 0;
247 }
248 
249 static struct snd_pcm_hardware snd_em28xx_hw_capture = {
255 
256  .formats = SNDRV_PCM_FMTBIT_S16_LE,
257 
259 
260  .rate_min = 48000,
261  .rate_max = 48000,
262  .channels_min = 2,
263  .channels_max = 2,
264  .buffer_bytes_max = 62720 * 8, /* just about the value in usbaudio.c */
265  .period_bytes_min = 64, /* 12544/2, */
266  .period_bytes_max = 12544,
267  .periods_min = 2,
268  .periods_max = 98, /* 12544, */
269 };
270 
271 static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
272 {
273  struct em28xx *dev = snd_pcm_substream_chip(substream);
274  struct snd_pcm_runtime *runtime = substream->runtime;
275  int ret = 0;
276 
277  dprintk("opening device and trying to acquire exclusive lock\n");
278 
279  if (!dev) {
280  em28xx_err("BUG: em28xx can't find device struct."
281  " Can't proceed with open\n");
282  return -ENODEV;
283  }
284 
285  runtime->hw = snd_em28xx_hw_capture;
286  if ((dev->alt == 0 || dev->audio_ifnum) && dev->adev.users == 0) {
287  if (dev->audio_ifnum)
288  dev->alt = 1;
289  else
290  dev->alt = 7;
291 
292  dprintk("changing alternate number on interface %d to %d\n",
293  dev->audio_ifnum, dev->alt);
294  usb_set_interface(dev->udev, dev->audio_ifnum, dev->alt);
295 
296  /* Sets volume, mute, etc */
297  dev->mute = 0;
298  mutex_lock(&dev->lock);
299  ret = em28xx_audio_analog_set(dev);
300  if (ret < 0)
301  goto err;
302 
303  dev->adev.users++;
304  mutex_unlock(&dev->lock);
305  }
306 
308  dev->adev.capture_pcm_substream = substream;
309 
310  return 0;
311 err:
312  mutex_unlock(&dev->lock);
313 
314  em28xx_err("Error while configuring em28xx mixer\n");
315  return ret;
316 }
317 
318 static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
319 {
320  struct em28xx *dev = snd_pcm_substream_chip(substream);
321 
322  dprintk("closing device\n");
323 
324  dev->mute = 1;
325  mutex_lock(&dev->lock);
326  dev->adev.users--;
327  if (atomic_read(&dev->stream_started) > 0) {
328  atomic_set(&dev->stream_started, 0);
329  schedule_work(&dev->wq_trigger);
330  }
331 
333  if (substream->runtime->dma_area) {
334  dprintk("freeing\n");
335  vfree(substream->runtime->dma_area);
336  substream->runtime->dma_area = NULL;
337  }
338  mutex_unlock(&dev->lock);
339 
340  return 0;
341 }
342 
343 static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream,
344  struct snd_pcm_hw_params *hw_params)
345 {
346  int ret;
347 
348  dprintk("Setting capture parameters\n");
349 
350  ret = snd_pcm_alloc_vmalloc_buffer(substream,
351  params_buffer_bytes(hw_params));
352  if (ret < 0)
353  return ret;
354 #if 0
355  /* TODO: set up em28xx audio chip to deliver the correct audio format,
356  current default is 48000hz multiplexed => 96000hz mono
357  which shouldn't matter since analogue TV only supports mono */
358  unsigned int channels, rate, format;
359 
360  format = params_format(hw_params);
361  rate = params_rate(hw_params);
362  channels = params_channels(hw_params);
363 #endif
364 
365  return 0;
366 }
367 
368 static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream)
369 {
370  struct em28xx *dev = snd_pcm_substream_chip(substream);
371 
372  dprintk("Stop capture, if needed\n");
373 
374  if (atomic_read(&dev->stream_started) > 0) {
375  atomic_set(&dev->stream_started, 0);
376  schedule_work(&dev->wq_trigger);
377  }
378 
379  return 0;
380 }
381 
382 static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
383 {
384  struct em28xx *dev = snd_pcm_substream_chip(substream);
385 
386  dev->adev.hwptr_done_capture = 0;
387  dev->adev.capture_transfer_done = 0;
388 
389  return 0;
390 }
391 
392 static void audio_trigger(struct work_struct *work)
393 {
394  struct em28xx *dev = container_of(work, struct em28xx, wq_trigger);
395 
396  if (atomic_read(&dev->stream_started)) {
397  dprintk("starting capture");
398  em28xx_init_audio_isoc(dev);
399  } else {
400  dprintk("stopping capture");
401  em28xx_deinit_isoc_audio(dev);
402  }
403 }
404 
405 static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,
406  int cmd)
407 {
408  struct em28xx *dev = snd_pcm_substream_chip(substream);
409  int retval = 0;
410 
411  switch (cmd) {
412  case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
413  case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
415  atomic_set(&dev->stream_started, 1);
416  break;
417  case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
418  case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
420  atomic_set(&dev->stream_started, 0);
421  break;
422  default:
423  retval = -EINVAL;
424  }
425  schedule_work(&dev->wq_trigger);
426  return retval;
427 }
428 
429 static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
430  *substream)
431 {
432  unsigned long flags;
433  struct em28xx *dev;
434  snd_pcm_uframes_t hwptr_done;
435 
436  dev = snd_pcm_substream_chip(substream);
437  spin_lock_irqsave(&dev->adev.slock, flags);
438  hwptr_done = dev->adev.hwptr_done_capture;
439  spin_unlock_irqrestore(&dev->adev.slock, flags);
440 
441  return hwptr_done;
442 }
443 
444 static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs,
445  unsigned long offset)
446 {
447  void *pageptr = subs->runtime->dma_area + offset;
448 
449  return vmalloc_to_page(pageptr);
450 }
451 
452 /*
453  * AC97 volume control support
454  */
455 static int em28xx_vol_info(struct snd_kcontrol *kcontrol,
456  struct snd_ctl_elem_info *info)
457 {
459  info->count = 2;
460  info->value.integer.min = 0;
461  info->value.integer.max = 0x1f;
462 
463  return 0;
464 }
465 
466 static int em28xx_vol_put(struct snd_kcontrol *kcontrol,
467  struct snd_ctl_elem_value *value)
468 {
469  struct em28xx *dev = snd_kcontrol_chip(kcontrol);
470  u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) |
471  (0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
472  int rc;
473 
474  mutex_lock(&dev->lock);
475  rc = em28xx_read_ac97(dev, kcontrol->private_value);
476  if (rc < 0)
477  goto err;
478 
479  val |= rc & 0x8000; /* Preserve the mute flag */
480 
481  rc = em28xx_write_ac97(dev, kcontrol->private_value, val);
482  if (rc < 0)
483  goto err;
484 
485  dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
486  (val & 0x8000) ? "muted " : "",
487  0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
488  val, (int)kcontrol->private_value);
489 
490 err:
491  mutex_unlock(&dev->lock);
492  return rc;
493 }
494 
495 static int em28xx_vol_get(struct snd_kcontrol *kcontrol,
496  struct snd_ctl_elem_value *value)
497 {
498  struct em28xx *dev = snd_kcontrol_chip(kcontrol);
499  int val;
500 
501  mutex_lock(&dev->lock);
502  val = em28xx_read_ac97(dev, kcontrol->private_value);
503  mutex_unlock(&dev->lock);
504  if (val < 0)
505  return val;
506 
507  dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
508  (val & 0x8000) ? "muted " : "",
509  0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
510  val, (int)kcontrol->private_value);
511 
512  value->value.integer.value[0] = 0x1f - (val & 0x1f);
513  value->value.integer.value[1] = 0x1f - ((val << 8) & 0x1f);
514 
515  return 0;
516 }
517 
518 static int em28xx_vol_put_mute(struct snd_kcontrol *kcontrol,
519  struct snd_ctl_elem_value *value)
520 {
521  struct em28xx *dev = snd_kcontrol_chip(kcontrol);
522  u16 val = value->value.integer.value[0];
523  int rc;
524 
525  mutex_lock(&dev->lock);
526  rc = em28xx_read_ac97(dev, kcontrol->private_value);
527  if (rc < 0)
528  goto err;
529 
530  if (val)
531  rc &= 0x1f1f;
532  else
533  rc |= 0x8000;
534 
535  rc = em28xx_write_ac97(dev, kcontrol->private_value, rc);
536  if (rc < 0)
537  goto err;
538 
539  dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
540  (val & 0x8000) ? "muted " : "",
541  0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
542  val, (int)kcontrol->private_value);
543 
544 err:
545  mutex_unlock(&dev->lock);
546  return rc;
547 }
548 
549 static int em28xx_vol_get_mute(struct snd_kcontrol *kcontrol,
550  struct snd_ctl_elem_value *value)
551 {
552  struct em28xx *dev = snd_kcontrol_chip(kcontrol);
553  int val;
554 
555  mutex_lock(&dev->lock);
556  val = em28xx_read_ac97(dev, kcontrol->private_value);
557  mutex_unlock(&dev->lock);
558  if (val < 0)
559  return val;
560 
561  if (val & 0x8000)
562  value->value.integer.value[0] = 0;
563  else
564  value->value.integer.value[0] = 1;
565 
566  dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
567  (val & 0x8000) ? "muted " : "",
568  0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
569  val, (int)kcontrol->private_value);
570 
571  return 0;
572 }
573 
574 static const DECLARE_TLV_DB_SCALE(em28xx_db_scale, -3450, 150, 0);
575 
576 static int em28xx_cvol_new(struct snd_card *card, struct em28xx *dev,
577  char *name, int id)
578 {
579  int err;
580  char ctl_name[44];
581  struct snd_kcontrol *kctl;
582  struct snd_kcontrol_new tmp;
583 
584  memset (&tmp, 0, sizeof(tmp));
586  tmp.private_value = id,
587  tmp.name = ctl_name,
588 
589  /* Add Mute Control */
590  sprintf(ctl_name, "%s Switch", name);
591  tmp.get = em28xx_vol_get_mute;
592  tmp.put = em28xx_vol_put_mute;
594  kctl = snd_ctl_new1(&tmp, dev);
595  err = snd_ctl_add(card, kctl);
596  if (err < 0)
597  return err;
598  dprintk("Added control %s for ac97 volume control 0x%04x\n",
599  ctl_name, id);
600 
601  memset (&tmp, 0, sizeof(tmp));
603  tmp.private_value = id,
604  tmp.name = ctl_name,
605 
606  /* Add Volume Control */
607  sprintf(ctl_name, "%s Volume", name);
608  tmp.get = em28xx_vol_get;
609  tmp.put = em28xx_vol_put;
610  tmp.info = em28xx_vol_info;
611  tmp.tlv.p = em28xx_db_scale,
612  kctl = snd_ctl_new1(&tmp, dev);
613  err = snd_ctl_add(card, kctl);
614  if (err < 0)
615  return err;
616  dprintk("Added control %s for ac97 volume control 0x%04x\n",
617  ctl_name, id);
618 
619  return 0;
620 }
621 
622 /*
623  * register/unregister code and data
624  */
625 static struct snd_pcm_ops snd_em28xx_pcm_capture = {
626  .open = snd_em28xx_capture_open,
627  .close = snd_em28xx_pcm_close,
628  .ioctl = snd_pcm_lib_ioctl,
629  .hw_params = snd_em28xx_hw_capture_params,
630  .hw_free = snd_em28xx_hw_capture_free,
631  .prepare = snd_em28xx_prepare,
632  .trigger = snd_em28xx_capture_trigger,
633  .pointer = snd_em28xx_capture_pointer,
634  .page = snd_pcm_get_vmalloc_page,
635 };
636 
637 static int em28xx_audio_init(struct em28xx *dev)
638 {
639  struct em28xx_audio *adev = &dev->adev;
640  struct snd_pcm *pcm;
641  struct snd_card *card;
642  static int devnr;
643  int err;
644 
645  if (!dev->has_alsa_audio || dev->audio_ifnum < 0) {
646  /* This device does not support the extension (in this case
647  the device is expecting the snd-usb-audio module or
648  doesn't have analog audio support at all) */
649  return 0;
650  }
651 
652  printk(KERN_INFO "em28xx-audio.c: probing for em28xx Audio Vendor Class\n");
653  printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
654  "Rechberger\n");
655  printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2007-2011 Mauro Carvalho Chehab\n");
656 
657  err = snd_card_create(index[devnr], "Em28xx Audio", THIS_MODULE, 0,
658  &card);
659  if (err < 0)
660  return err;
661 
662  spin_lock_init(&adev->slock);
663  err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
664  if (err < 0) {
665  snd_card_free(card);
666  return err;
667  }
668 
669  snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
670  pcm->info_flags = 0;
671  pcm->private_data = dev;
672  strcpy(pcm->name, "Empia 28xx Capture");
673 
674  snd_card_set_dev(card, &dev->udev->dev);
675  strcpy(card->driver, "Em28xx-Audio");
676  strcpy(card->shortname, "Em28xx Audio");
677  strcpy(card->longname, "Empia Em28xx Audio");
678 
679  INIT_WORK(&dev->wq_trigger, audio_trigger);
680 
681  if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
682  em28xx_cvol_new(card, dev, "Video", AC97_VIDEO);
683  em28xx_cvol_new(card, dev, "Line In", AC97_LINE);
684  em28xx_cvol_new(card, dev, "Phone", AC97_PHONE);
685  em28xx_cvol_new(card, dev, "Microphone", AC97_MIC);
686  em28xx_cvol_new(card, dev, "CD", AC97_CD);
687  em28xx_cvol_new(card, dev, "AUX", AC97_AUX);
688  em28xx_cvol_new(card, dev, "PCM", AC97_PCM);
689 
690  em28xx_cvol_new(card, dev, "Master", AC97_MASTER);
691  em28xx_cvol_new(card, dev, "Line", AC97_HEADPHONE);
692  em28xx_cvol_new(card, dev, "Mono", AC97_MASTER_MONO);
693  em28xx_cvol_new(card, dev, "LFE", AC97_CENTER_LFE_MASTER);
694  em28xx_cvol_new(card, dev, "Surround", AC97_SURROUND_MASTER);
695  }
696 
697  err = snd_card_register(card);
698  if (err < 0) {
699  snd_card_free(card);
700  return err;
701  }
702  adev->sndcard = card;
703  adev->udev = dev->udev;
704 
705  return 0;
706 }
707 
708 static int em28xx_audio_fini(struct em28xx *dev)
709 {
710  if (dev == NULL)
711  return 0;
712 
713  if (dev->has_alsa_audio != 1) {
714  /* This device does not support the extension (in this case
715  the device is expecting the snd-usb-audio module or
716  doesn't have analog audio support at all) */
717  return 0;
718  }
719 
720  if (dev->adev.sndcard) {
721  snd_card_free(dev->adev.sndcard);
722  dev->adev.sndcard = NULL;
723  }
724 
725  return 0;
726 }
727 
728 static struct em28xx_ops audio_ops = {
729  .id = EM28XX_AUDIO,
730  .name = "Em28xx Audio Extension",
731  .init = em28xx_audio_init,
732  .fini = em28xx_audio_fini,
733 };
734 
735 static int __init em28xx_alsa_register(void)
736 {
737  return em28xx_register_extension(&audio_ops);
738 }
739 
740 static void __exit em28xx_alsa_unregister(void)
741 {
742  em28xx_unregister_extension(&audio_ops);
743 }
744 
745 MODULE_LICENSE("GPL");
746 MODULE_AUTHOR("Markus Rechberger <[email protected]>");
747 MODULE_AUTHOR("Mauro Carvalho Chehab <[email protected]>");
748 MODULE_DESCRIPTION("Em28xx Audio driver");
749 
750 module_init(em28xx_alsa_register);
751 module_exit(em28xx_alsa_unregister);