drivers/media/usb/em28xx/em28xx-audio.c - nest-hello/linux-3.10 - Git at Google

 /*
  *  Empiatech em28x1 audio extension
  *
  *  Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
  *
  *  Copyright (C) 2007-2011 Mauro Carvalho Chehab <mchehab@redhat.com>
  *	- Port to work with the in-kernel driver
  *	- Cleanups, fixes, alsa-controls, etc.
  *
  *  This driver is based on my previous au600 usb pstn audio driver
  *  and inherits all the copyrights
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/kernel.h>
 #include <linux/usb.h>
 #include <linux/init.h>
 #include <linux/sound.h>
 #include <linux/spinlock.h>
 #include <linux/soundcard.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/proc_fs.h>
 #include <linux/module.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/info.h>
 #include <sound/initval.h>
 #include <sound/control.h>
 #include <sound/tlv.h>
 #include <sound/ac97_codec.h>
 #include <media/v4l2-common.h>
 #include "em28xx.h"

 static int debug;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "activates debug info");

 #define dprintk(fmt, arg...) do {					\
 	    if (debug)							\
 		printk(KERN_INFO "em28xx-audio %s: " fmt,		\
 				  __func__, ##arg); 		\
 	} while (0)

 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;

 static int em28xx_deinit_isoc_audio(struct em28xx *dev)
 {
 	int i;

 	dprintk("Stopping isoc\n");
 	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
 		if (!irqs_disabled())
 			usb_kill_urb(dev->adev.urb[i]);
 		else
 			usb_unlink_urb(dev->adev.urb[i]);

 		usb_free_urb(dev->adev.urb[i]);
 		dev->adev.urb[i] = NULL;

 		kfree(dev->adev.transfer_buffer[i]);
 		dev->adev.transfer_buffer[i] = NULL;
 	}

 	return 0;
 }

 static void em28xx_audio_isocirq(struct urb *urb)
 {
 	struct em28xx            *dev = urb->context;
 	int                      i;
 	unsigned int             oldptr;
 	int                      period_elapsed = 0;
 	int                      status;
 	unsigned char            *cp;
 	unsigned int             stride;
 	struct snd_pcm_substream *substream;
 	struct snd_pcm_runtime   *runtime;

 	switch (urb->status) {
 	case 0:             /* success */
 	case -ETIMEDOUT:    /* NAK */
 		break;
 	case -ECONNRESET:   /* kill */
 	case -ENOENT:
 	case -ESHUTDOWN:
 		return;
 	default:            /* error */
 		dprintk("urb completition error %d.\n", urb->status);
 		break;
 	}

 	if (atomic_read(&dev->stream_started) == 0)
 		return;

 	if (dev->adev.capture_pcm_substream) {
 		substream = dev->adev.capture_pcm_substream;
 		runtime = substream->runtime;
 		stride = runtime->frame_bits >> 3;

 		for (i = 0; i < urb->number_of_packets; i++) {
 			int length =
 			    urb->iso_frame_desc[i].actual_length / stride;
 			cp = (unsigned char *)urb->transfer_buffer +
 			    urb->iso_frame_desc[i].offset;

 			if (!length)
 				continue;

 			oldptr = dev->adev.hwptr_done_capture;
 			if (oldptr + length >= runtime->buffer_size) {
 				unsigned int cnt =
 				    runtime->buffer_size - oldptr;
 				memcpy(runtime->dma_area + oldptr * stride, cp,
 				       cnt * stride);
 				memcpy(runtime->dma_area, cp + cnt * stride,
 				       length * stride - cnt * stride);
 			} else {
 				memcpy(runtime->dma_area + oldptr * stride, cp,
 				       length * stride);
 			}

 			snd_pcm_stream_lock(substream);

 			dev->adev.hwptr_done_capture += length;
 			if (dev->adev.hwptr_done_capture >=
 			    runtime->buffer_size)
 				dev->adev.hwptr_done_capture -=
 				    runtime->buffer_size;

 			dev->adev.capture_transfer_done += length;
 			if (dev->adev.capture_transfer_done >=
 			    runtime->period_size) {
 				dev->adev.capture_transfer_done -=
 				    runtime->period_size;
 				period_elapsed = 1;
 			}

 			snd_pcm_stream_unlock(substream);
 		}
 		if (period_elapsed)
 			snd_pcm_period_elapsed(substream);
 	}
 	urb->status = 0;

 	status = usb_submit_urb(urb, GFP_ATOMIC);
 	if (status < 0) {
 		em28xx_errdev("resubmit of audio urb failed (error=%i)\n",
 			      status);
 	}
 	return;
 }

 static int em28xx_init_audio_isoc(struct em28xx *dev)
 {
 	int       i, errCode;
 	const int sb_size = EM28XX_NUM_AUDIO_PACKETS *
 			    EM28XX_AUDIO_MAX_PACKET_SIZE;

 	dprintk("Starting isoc transfers\n");

 	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
 		struct urb *urb;
 		int j, k;

 		dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
 		if (!dev->adev.transfer_buffer[i])
 			return -ENOMEM;

 		memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
 		urb = usb_alloc_urb(EM28XX_NUM_AUDIO_PACKETS, GFP_ATOMIC);
 		if (!urb) {
 			em28xx_errdev("usb_alloc_urb failed!\n");
 			for (j = 0; j < i; j++) {
 				usb_free_urb(dev->adev.urb[j]);
 				kfree(dev->adev.transfer_buffer[j]);
 			}
 			return -ENOMEM;
 		}

 		urb->dev = dev->udev;
 		urb->context = dev;
 		urb->pipe = usb_rcvisocpipe(dev->udev, EM28XX_EP_AUDIO);
 		urb->transfer_flags = URB_ISO_ASAP;
 		urb->transfer_buffer = dev->adev.transfer_buffer[i];
 		urb->interval = 1;
 		urb->complete = em28xx_audio_isocirq;
 		urb->number_of_packets = EM28XX_NUM_AUDIO_PACKETS;
 		urb->transfer_buffer_length = sb_size;

 		for (j = k = 0; j < EM28XX_NUM_AUDIO_PACKETS;
 			     j++, k += EM28XX_AUDIO_MAX_PACKET_SIZE) {
 			urb->iso_frame_desc[j].offset = k;
 			urb->iso_frame_desc[j].length =
 			    EM28XX_AUDIO_MAX_PACKET_SIZE;
 		}
 		dev->adev.urb[i] = urb;
 	}

 	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
 		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
 		if (errCode) {
 			em28xx_errdev("submit of audio urb failed\n");
 			em28xx_deinit_isoc_audio(dev);
 			atomic_set(&dev->stream_started, 0);
 			return errCode;
 		}

 	}

 	return 0;
 }

 static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,
 					size_t size)
 {
 	struct snd_pcm_runtime *runtime = subs->runtime;

 	dprintk("Allocating vbuffer\n");
 	if (runtime->dma_area) {
 		if (runtime->dma_bytes > size)
 			return 0;

 		vfree(runtime->dma_area);
 	}
 	runtime->dma_area = vmalloc(size);
 	if (!runtime->dma_area)
 		return -ENOMEM;

 	runtime->dma_bytes = size;

 	return 0;
 }

 static struct snd_pcm_hardware snd_em28xx_hw_capture = {
 	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		SNDRV_PCM_INFO_MMAP           |
 		SNDRV_PCM_INFO_INTERLEAVED    |
 		SNDRV_PCM_INFO_BATCH	      |
 		SNDRV_PCM_INFO_MMAP_VALID,

 	.formats = SNDRV_PCM_FMTBIT_S16_LE,

 	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_KNOT,

 	.rate_min = 48000,
 	.rate_max = 48000,
 	.channels_min = 2,
 	.channels_max = 2,
 	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
 	.period_bytes_min = 64,		/* 12544/2, */
 	.period_bytes_max = 12544,
 	.periods_min = 2,
 	.periods_max = 98,		/* 12544, */
 };

 static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
 {
 	struct em28xx *dev = snd_pcm_substream_chip(substream);
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int ret = 0;

 	dprintk("opening device and trying to acquire exclusive lock\n");

 	if (!dev) {
 		em28xx_err("BUG: em28xx can't find device struct."
 				" Can't proceed with open\n");
 		return -ENODEV;
 	}

 	runtime->hw = snd_em28xx_hw_capture;
 	if ((dev->alt == 0 || dev->audio_ifnum) && dev->adev.users == 0) {
 		if (dev->audio_ifnum)
 			dev->alt = 1;
 		else
 			dev->alt = 7;

 		dprintk("changing alternate number on interface %d to %d\n",
 			dev->audio_ifnum, dev->alt);
 		usb_set_interface(dev->udev, dev->audio_ifnum, dev->alt);

 		/* Sets volume, mute, etc */
 		dev->mute = 0;
 		mutex_lock(&dev->lock);
 		ret = em28xx_audio_analog_set(dev);
 		if (ret < 0)
 			goto err;

 		dev->adev.users++;
 		mutex_unlock(&dev->lock);
 	}

 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 	dev->adev.capture_pcm_substream = substream;

 	return 0;
 err:
 	mutex_unlock(&dev->lock);

 	em28xx_err("Error while configuring em28xx mixer\n");
 	return ret;
 }

 static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
 {
 	struct em28xx *dev = snd_pcm_substream_chip(substream);

 	dprintk("closing device\n");

 	dev->mute = 1;
 	mutex_lock(&dev->lock);
 	dev->adev.users--;
 	if (atomic_read(&dev->stream_started) > 0) {
 		atomic_set(&dev->stream_started, 0);
 		schedule_work(&dev->wq_trigger);
 	}

 	em28xx_audio_analog_set(dev);
 	if (substream->runtime->dma_area) {
 		dprintk("freeing\n");
 		vfree(substream->runtime->dma_area);
 		substream->runtime->dma_area = NULL;
 	}
 	mutex_unlock(&dev->lock);

 	return 0;
 }

 static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream,
 					struct snd_pcm_hw_params *hw_params)
 {
 	int ret;

 	dprintk("Setting capture parameters\n");

 	ret = snd_pcm_alloc_vmalloc_buffer(substream,
 				params_buffer_bytes(hw_params));
 	if (ret < 0)
 		return ret;
 #if 0
 	/* TODO: set up em28xx audio chip to deliver the correct audio format,
 	   current default is 48000hz multiplexed => 96000hz mono
 	   which shouldn't matter since analogue TV only supports mono */
 	unsigned int channels, rate, format;

 	format = params_format(hw_params);
 	rate = params_rate(hw_params);
 	channels = params_channels(hw_params);
 #endif

 	return 0;
 }

 static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream)
 {
 	struct em28xx *dev = snd_pcm_substream_chip(substream);

 	dprintk("Stop capture, if needed\n");

 	if (atomic_read(&dev->stream_started) > 0) {
 		atomic_set(&dev->stream_started, 0);
 		schedule_work(&dev->wq_trigger);
 	}

 	return 0;
 }

 static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
 {
 	struct em28xx *dev = snd_pcm_substream_chip(substream);

 	dev->adev.hwptr_done_capture = 0;
 	dev->adev.capture_transfer_done = 0;

 	return 0;
 }

 static void audio_trigger(struct work_struct *work)
 {
 	struct em28xx *dev = container_of(work, struct em28xx, wq_trigger);

 	if (atomic_read(&dev->stream_started)) {
 		dprintk("starting capture");
 		em28xx_init_audio_isoc(dev);
 	} else {
 		dprintk("stopping capture");
 		em28xx_deinit_isoc_audio(dev);
 	}
 }

 static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,
 				      int cmd)
 {
 	struct em28xx *dev = snd_pcm_substream_chip(substream);
 	int retval = 0;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
 	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
 	case SNDRV_PCM_TRIGGER_START:
 		atomic_set(&dev->stream_started, 1);
 		break;
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
 	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
 	case SNDRV_PCM_TRIGGER_STOP:
 		atomic_set(&dev->stream_started, 0);
 		break;
 	default:
 		retval = -EINVAL;
 	}
 	schedule_work(&dev->wq_trigger);
 	return retval;
 }

 static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
 						    *substream)
 {
 	unsigned long flags;
 	struct em28xx *dev;
 	snd_pcm_uframes_t hwptr_done;

 	dev = snd_pcm_substream_chip(substream);
 	spin_lock_irqsave(&dev->adev.slock, flags);
 	hwptr_done = dev->adev.hwptr_done_capture;
 	spin_unlock_irqrestore(&dev->adev.slock, flags);

 	return hwptr_done;
 }

 static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs,
 					     unsigned long offset)
 {
 	void *pageptr = subs->runtime->dma_area + offset;

 	return vmalloc_to_page(pageptr);
 }

 /*
  * AC97 volume control support
  */
 static int em28xx_vol_info(struct snd_kcontrol *kcontrol,
 				struct snd_ctl_elem_info *info)
 {
 	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 	info->count = 2;
 	info->value.integer.min = 0;
 	info->value.integer.max = 0x1f;

 	return 0;
 }

 static int em28xx_vol_put(struct snd_kcontrol *kcontrol,
 			       struct snd_ctl_elem_value *value)
 {
 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
 	u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) |
 		  (0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
 	int rc;

 	mutex_lock(&dev->lock);
 	rc = em28xx_read_ac97(dev, kcontrol->private_value);
 	if (rc < 0)
 		goto err;

 	val |= rc & 0x8000;	/* Preserve the mute flag */

 	rc = em28xx_write_ac97(dev, kcontrol->private_value, val);
 	if (rc < 0)
 		goto err;

 	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
 		(val & 0x8000) ? "muted " : "",
 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
 		val, (int)kcontrol->private_value);

 err:
 	mutex_unlock(&dev->lock);
 	return rc;
 }

 static int em28xx_vol_get(struct snd_kcontrol *kcontrol,
 			       struct snd_ctl_elem_value *value)
 {
 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
 	int val;

 	mutex_lock(&dev->lock);
 	val = em28xx_read_ac97(dev, kcontrol->private_value);
 	mutex_unlock(&dev->lock);
 	if (val < 0)
 		return val;

 	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
 		(val & 0x8000) ? "muted " : "",
 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
 		val, (int)kcontrol->private_value);

 	value->value.integer.value[0] = 0x1f - (val & 0x1f);
 	value->value.integer.value[1] = 0x1f - ((val << 8) & 0x1f);

 	return 0;
 }

 static int em28xx_vol_put_mute(struct snd_kcontrol *kcontrol,
 			       struct snd_ctl_elem_value *value)
 {
 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
 	u16 val = value->value.integer.value[0];
 	int rc;

 	mutex_lock(&dev->lock);
 	rc = em28xx_read_ac97(dev, kcontrol->private_value);
 	if (rc < 0)
 		goto err;

 	if (val)
 		rc &= 0x1f1f;
 	else
 		rc |= 0x8000;

 	rc = em28xx_write_ac97(dev, kcontrol->private_value, rc);
 	if (rc < 0)
 		goto err;

 	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
 		(val & 0x8000) ? "muted " : "",
 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
 		val, (int)kcontrol->private_value);

 err:
 	mutex_unlock(&dev->lock);
 	return rc;
 }

 static int em28xx_vol_get_mute(struct snd_kcontrol *kcontrol,
 			       struct snd_ctl_elem_value *value)
 {
 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
 	int val;

 	mutex_lock(&dev->lock);
 	val = em28xx_read_ac97(dev, kcontrol->private_value);
 	mutex_unlock(&dev->lock);
 	if (val < 0)
 		return val;

 	if (val & 0x8000)
 		value->value.integer.value[0] = 0;
 	else
 		value->value.integer.value[0] = 1;

 	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
 		(val & 0x8000) ? "muted " : "",
 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
 		val, (int)kcontrol->private_value);

 	return 0;
 }

 static const DECLARE_TLV_DB_SCALE(em28xx_db_scale, -3450, 150, 0);

 static int em28xx_cvol_new(struct snd_card *card, struct em28xx *dev,
 			   char *name, int id)
 {
 	int err;
 	char ctl_name[44];
 	struct snd_kcontrol *kctl;
 	struct snd_kcontrol_new tmp;

 	memset (&tmp, 0, sizeof(tmp));
 	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	tmp.private_value = id,
 	tmp.name  = ctl_name,

 	/* Add Mute Control */
 	sprintf(ctl_name, "%s Switch", name);
 	tmp.get  = em28xx_vol_get_mute;
 	tmp.put  = em28xx_vol_put_mute;
 	tmp.info = snd_ctl_boolean_mono_info;
 	kctl = snd_ctl_new1(&tmp, dev);
 	err = snd_ctl_add(card, kctl);
 	if (err < 0)
 		return err;
 	dprintk("Added control %s for ac97 volume control 0x%04x\n",
 		ctl_name, id);

 	memset (&tmp, 0, sizeof(tmp));
 	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	tmp.private_value = id,
 	tmp.name  = ctl_name,

 	/* Add Volume Control */
 	sprintf(ctl_name, "%s Volume", name);
 	tmp.get   = em28xx_vol_get;
 	tmp.put   = em28xx_vol_put;
 	tmp.info  = em28xx_vol_info;
 	tmp.tlv.p = em28xx_db_scale,
 	kctl = snd_ctl_new1(&tmp, dev);
 	err = snd_ctl_add(card, kctl);
 	if (err < 0)
 		return err;
 	dprintk("Added control %s for ac97 volume control 0x%04x\n",
 		ctl_name, id);

 	return 0;
 }

 /*
  * register/unregister code and data
  */
 static struct snd_pcm_ops snd_em28xx_pcm_capture = {
 	.open      = snd_em28xx_capture_open,
 	.close     = snd_em28xx_pcm_close,
 	.ioctl     = snd_pcm_lib_ioctl,
 	.hw_params = snd_em28xx_hw_capture_params,
 	.hw_free   = snd_em28xx_hw_capture_free,
 	.prepare   = snd_em28xx_prepare,
 	.trigger   = snd_em28xx_capture_trigger,
 	.pointer   = snd_em28xx_capture_pointer,
 	.page      = snd_pcm_get_vmalloc_page,
 };

 static int em28xx_audio_init(struct em28xx *dev)
 {
 	struct em28xx_audio *adev = &dev->adev;
 	struct snd_pcm      *pcm;
 	struct snd_card     *card;
 	static int          devnr;
 	int                 err;

 	if (!dev->has_alsa_audio || dev->audio_ifnum < 0) {
 		/* This device does not support the extension (in this case
 		   the device is expecting the snd-usb-audio module or
 		   doesn't have analog audio support at all) */
 		return 0;
 	}

 	printk(KERN_INFO "em28xx-audio.c: probing for em28xx Audio Vendor Class\n");
 	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
 			 "Rechberger\n");
 	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2007-2011 Mauro Carvalho Chehab\n");

 	err = snd_card_create(index[devnr], "Em28xx Audio", THIS_MODULE, 0,
 			      &card);
 	if (err < 0)
 		return err;

 	spin_lock_init(&adev->slock);
 	err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
 	if (err < 0) {
 		snd_card_free(card);
 		return err;
 	}

 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
 	pcm->info_flags = 0;
 	pcm->private_data = dev;
 	strcpy(pcm->name, "Empia 28xx Capture");

 	snd_card_set_dev(card, &dev->udev->dev);
 	strcpy(card->driver, "Em28xx-Audio");
 	strcpy(card->shortname, "Em28xx Audio");
 	strcpy(card->longname, "Empia Em28xx Audio");

 	INIT_WORK(&dev->wq_trigger, audio_trigger);

 	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
 		em28xx_cvol_new(card, dev, "Video", AC97_VIDEO);
 		em28xx_cvol_new(card, dev, "Line In", AC97_LINE);
 		em28xx_cvol_new(card, dev, "Phone", AC97_PHONE);
 		em28xx_cvol_new(card, dev, "Microphone", AC97_MIC);
 		em28xx_cvol_new(card, dev, "CD", AC97_CD);
 		em28xx_cvol_new(card, dev, "AUX", AC97_AUX);
 		em28xx_cvol_new(card, dev, "PCM", AC97_PCM);

 		em28xx_cvol_new(card, dev, "Master", AC97_MASTER);
 		em28xx_cvol_new(card, dev, "Line", AC97_HEADPHONE);
 		em28xx_cvol_new(card, dev, "Mono", AC97_MASTER_MONO);
 		em28xx_cvol_new(card, dev, "LFE", AC97_CENTER_LFE_MASTER);
 		em28xx_cvol_new(card, dev, "Surround", AC97_SURROUND_MASTER);
 	}

 	err = snd_card_register(card);
 	if (err < 0) {
 		snd_card_free(card);
 		return err;
 	}
 	adev->sndcard = card;
 	adev->udev = dev->udev;

 	return 0;
 }

 static int em28xx_audio_fini(struct em28xx *dev)
 {
 	if (dev == NULL)
 		return 0;

 	if (dev->has_alsa_audio != 1) {
 		/* This device does not support the extension (in this case
 		   the device is expecting the snd-usb-audio module or
 		   doesn't have analog audio support at all) */
 		return 0;
 	}

 	if (dev->adev.sndcard) {
 		snd_card_free(dev->adev.sndcard);
 		dev->adev.sndcard = NULL;
 	}

 	return 0;
 }

 static struct em28xx_ops audio_ops = {
 	.id   = EM28XX_AUDIO,
 	.name = "Em28xx Audio Extension",
 	.init = em28xx_audio_init,
 	.fini = em28xx_audio_fini,
 };

 static int __init em28xx_alsa_register(void)
 {
 	return em28xx_register_extension(&audio_ops);
 }

 static void __exit em28xx_alsa_unregister(void)
 {
 	em28xx_unregister_extension(&audio_ops);
 }

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Markus Rechberger <mrechberger@gmail.com>");
 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
 MODULE_DESCRIPTION("Em28xx Audio driver");

 module_init(em28xx_alsa_register);
 module_exit(em28xx_alsa_unregister);
	/*
	* Empiatech em28x1 audio extension
	*
	* Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
	*
	* Copyright (C) 2007-2011 Mauro Carvalho Chehab <mchehab@redhat.com>
	* - Port to work with the in-kernel driver
	* - Cleanups, fixes, alsa-controls, etc.
	*
	* This driver is based on my previous au600 usb pstn audio driver
	* and inherits all the copyrights
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/kernel.h>
	#include <linux/usb.h>
	#include <linux/init.h>
	#include <linux/sound.h>
	#include <linux/spinlock.h>
	#include <linux/soundcard.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/proc_fs.h>
	#include <linux/module.h>
	#include <sound/core.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/info.h>
	#include <sound/initval.h>
	#include <sound/control.h>
	#include <sound/tlv.h>
	#include <sound/ac97_codec.h>
	#include <media/v4l2-common.h>
	#include "em28xx.h"

	static int debug;
	module_param(debug, int, 0644);
	MODULE_PARM_DESC(debug, "activates debug info");

	#define dprintk(fmt, arg...) do { \
	if (debug) \
	printk(KERN_INFO "em28xx-audio %s: " fmt, \
	__func__, ##arg); \
	} while (0)

	static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;

	static int em28xx_deinit_isoc_audio(struct em28xx *dev)
	{
	int i;

	dprintk("Stopping isoc\n");
	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
	if (!irqs_disabled())
	usb_kill_urb(dev->adev.urb[i]);
	else
	usb_unlink_urb(dev->adev.urb[i]);

	usb_free_urb(dev->adev.urb[i]);
	dev->adev.urb[i] = NULL;

	kfree(dev->adev.transfer_buffer[i]);
	dev->adev.transfer_buffer[i] = NULL;
	}

	return 0;
	}

	static void em28xx_audio_isocirq(struct urb *urb)
	{
	struct em28xx *dev = urb->context;
	int i;
	unsigned int oldptr;
	int period_elapsed = 0;
	int status;
	unsigned char *cp;
	unsigned int stride;
	struct snd_pcm_substream *substream;
	struct snd_pcm_runtime *runtime;

	switch (urb->status) {
	case 0: /* success */
	case -ETIMEDOUT: /* NAK */
	break;
	case -ECONNRESET: /* kill */
	case -ENOENT:
	case -ESHUTDOWN:
	return;
	default: /* error */
	dprintk("urb completition error %d.\n", urb->status);
	break;
	}

	if (atomic_read(&dev->stream_started) == 0)
	return;

	if (dev->adev.capture_pcm_substream) {
	substream = dev->adev.capture_pcm_substream;
	runtime = substream->runtime;
	stride = runtime->frame_bits >> 3;

	for (i = 0; i < urb->number_of_packets; i++) {
	int length =
	urb->iso_frame_desc[i].actual_length / stride;
	cp = (unsigned char *)urb->transfer_buffer +
	urb->iso_frame_desc[i].offset;

	if (!length)
	continue;

	oldptr = dev->adev.hwptr_done_capture;
	if (oldptr + length >= runtime->buffer_size) {
	unsigned int cnt =
	runtime->buffer_size - oldptr;
	memcpy(runtime->dma_area + oldptr * stride, cp,
	cnt * stride);
	memcpy(runtime->dma_area, cp + cnt * stride,
	length * stride - cnt * stride);
	} else {
	memcpy(runtime->dma_area + oldptr * stride, cp,
	length * stride);
	}

	snd_pcm_stream_lock(substream);

	dev->adev.hwptr_done_capture += length;
	if (dev->adev.hwptr_done_capture >=
	runtime->buffer_size)
	dev->adev.hwptr_done_capture -=
	runtime->buffer_size;

	dev->adev.capture_transfer_done += length;
	if (dev->adev.capture_transfer_done >=
	runtime->period_size) {
	dev->adev.capture_transfer_done -=
	runtime->period_size;
	period_elapsed = 1;
	}

	snd_pcm_stream_unlock(substream);
	}
	if (period_elapsed)
	snd_pcm_period_elapsed(substream);
	}
	urb->status = 0;

	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status < 0) {
	em28xx_errdev("resubmit of audio urb failed (error=%i)\n",
	status);
	}
	return;
	}

	static int em28xx_init_audio_isoc(struct em28xx *dev)
	{
	int i, errCode;
	const int sb_size = EM28XX_NUM_AUDIO_PACKETS *
	EM28XX_AUDIO_MAX_PACKET_SIZE;

	dprintk("Starting isoc transfers\n");

	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
	struct urb *urb;
	int j, k;

	dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
	if (!dev->adev.transfer_buffer[i])
	return -ENOMEM;

	memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
	urb = usb_alloc_urb(EM28XX_NUM_AUDIO_PACKETS, GFP_ATOMIC);
	if (!urb) {
	em28xx_errdev("usb_alloc_urb failed!\n");
	for (j = 0; j < i; j++) {
	usb_free_urb(dev->adev.urb[j]);
	kfree(dev->adev.transfer_buffer[j]);
	}
	return -ENOMEM;
	}

	urb->dev = dev->udev;
	urb->context = dev;
	urb->pipe = usb_rcvisocpipe(dev->udev, EM28XX_EP_AUDIO);
	urb->transfer_flags = URB_ISO_ASAP;
	urb->transfer_buffer = dev->adev.transfer_buffer[i];
	urb->interval = 1;
	urb->complete = em28xx_audio_isocirq;
	urb->number_of_packets = EM28XX_NUM_AUDIO_PACKETS;
	urb->transfer_buffer_length = sb_size;

	for (j = k = 0; j < EM28XX_NUM_AUDIO_PACKETS;
	j++, k += EM28XX_AUDIO_MAX_PACKET_SIZE) {
	urb->iso_frame_desc[j].offset = k;
	urb->iso_frame_desc[j].length =
	EM28XX_AUDIO_MAX_PACKET_SIZE;
	}
	dev->adev.urb[i] = urb;
	}

	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
	errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
	if (errCode) {
	em28xx_errdev("submit of audio urb failed\n");
	em28xx_deinit_isoc_audio(dev);
	atomic_set(&dev->stream_started, 0);
	return errCode;
	}

	}

	return 0;
	}

	static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,
	size_t size)
	{
	struct snd_pcm_runtime *runtime = subs->runtime;

	dprintk("Allocating vbuffer\n");
	if (runtime->dma_area) {
	if (runtime->dma_bytes > size)
	return 0;

	vfree(runtime->dma_area);
	}
	runtime->dma_area = vmalloc(size);
	if (!runtime->dma_area)
	return -ENOMEM;

	runtime->dma_bytes = size;

	return 0;
	}

	static struct snd_pcm_hardware snd_em28xx_hw_capture = {
	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_BATCH \|
	SNDRV_PCM_INFO_MMAP_VALID,

	.formats = SNDRV_PCM_FMTBIT_S16_LE,

	.rates = SNDRV_PCM_RATE_CONTINUOUS \| SNDRV_PCM_RATE_KNOT,

	.rate_min = 48000,
	.rate_max = 48000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = 62720 * 8, /* just about the value in usbaudio.c */
	.period_bytes_min = 64, /* 12544/2, */
	.period_bytes_max = 12544,
	.periods_min = 2,
	.periods_max = 98, /* 12544, */
	};

	static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
	{
	struct em28xx *dev = snd_pcm_substream_chip(substream);
	struct snd_pcm_runtime *runtime = substream->runtime;
	int ret = 0;

	dprintk("opening device and trying to acquire exclusive lock\n");

	if (!dev) {
	em28xx_err("BUG: em28xx can't find device struct."
	" Can't proceed with open\n");
	return -ENODEV;
	}

	runtime->hw = snd_em28xx_hw_capture;
	if ((dev->alt == 0 \|\| dev->audio_ifnum) && dev->adev.users == 0) {
	if (dev->audio_ifnum)
	dev->alt = 1;
	else
	dev->alt = 7;

	dprintk("changing alternate number on interface %d to %d\n",
	dev->audio_ifnum, dev->alt);
	usb_set_interface(dev->udev, dev->audio_ifnum, dev->alt);

	/* Sets volume, mute, etc */
	dev->mute = 0;
	mutex_lock(&dev->lock);
	ret = em28xx_audio_analog_set(dev);
	if (ret < 0)
	goto err;

	dev->adev.users++;
	mutex_unlock(&dev->lock);
	}

	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	dev->adev.capture_pcm_substream = substream;

	return 0;
	err:
	mutex_unlock(&dev->lock);

	em28xx_err("Error while configuring em28xx mixer\n");
	return ret;
	}

	static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
	{
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	dprintk("closing device\n");

	dev->mute = 1;
	mutex_lock(&dev->lock);
	dev->adev.users--;
	if (atomic_read(&dev->stream_started) > 0) {
	atomic_set(&dev->stream_started, 0);
	schedule_work(&dev->wq_trigger);
	}

	em28xx_audio_analog_set(dev);
	if (substream->runtime->dma_area) {
	dprintk("freeing\n");
	vfree(substream->runtime->dma_area);
	substream->runtime->dma_area = NULL;
	}
	mutex_unlock(&dev->lock);

	return 0;
	}

	static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *hw_params)
	{
	int ret;

	dprintk("Setting capture parameters\n");

	ret = snd_pcm_alloc_vmalloc_buffer(substream,
	params_buffer_bytes(hw_params));
	if (ret < 0)
	return ret;
	#if 0
	/* TODO: set up em28xx audio chip to deliver the correct audio format,
	current default is 48000hz multiplexed => 96000hz mono
	which shouldn't matter since analogue TV only supports mono */
	unsigned int channels, rate, format;

	format = params_format(hw_params);
	rate = params_rate(hw_params);
	channels = params_channels(hw_params);
	#endif

	return 0;
	}

	static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream)
	{
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	dprintk("Stop capture, if needed\n");

	if (atomic_read(&dev->stream_started) > 0) {
	atomic_set(&dev->stream_started, 0);
	schedule_work(&dev->wq_trigger);
	}

	return 0;
	}

	static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
	{
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	dev->adev.hwptr_done_capture = 0;
	dev->adev.capture_transfer_done = 0;

	return 0;
	}

	static void audio_trigger(struct work_struct *work)
	{
	struct em28xx *dev = container_of(work, struct em28xx, wq_trigger);

	if (atomic_read(&dev->stream_started)) {
	dprintk("starting capture");
	em28xx_init_audio_isoc(dev);
	} else {
	dprintk("stopping capture");
	em28xx_deinit_isoc_audio(dev);
	}
	}

	static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,
	int cmd)
	{
	struct em28xx *dev = snd_pcm_substream_chip(substream);
	int retval = 0;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
	case SNDRV_PCM_TRIGGER_START:
	atomic_set(&dev->stream_started, 1);
	break;
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
	case SNDRV_PCM_TRIGGER_STOP:
	atomic_set(&dev->stream_started, 0);
	break;
	default:
	retval = -EINVAL;
	}
	schedule_work(&dev->wq_trigger);
	return retval;
	}

	static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
	*substream)
	{
	unsigned long flags;
	struct em28xx *dev;
	snd_pcm_uframes_t hwptr_done;

	dev = snd_pcm_substream_chip(substream);
	spin_lock_irqsave(&dev->adev.slock, flags);
	hwptr_done = dev->adev.hwptr_done_capture;
	spin_unlock_irqrestore(&dev->adev.slock, flags);

	return hwptr_done;
	}

	static struct page snd_pcm_get_vmalloc_page(struct snd_pcm_substream subs,
	unsigned long offset)
	{
	void *pageptr = subs->runtime->dma_area + offset;

	return vmalloc_to_page(pageptr);
	}

	/*
	* AC97 volume control support
	*/
	static int em28xx_vol_info(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_info *info)
	{
	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	info->count = 2;
	info->value.integer.min = 0;
	info->value.integer.max = 0x1f;

	return 0;
	}

	static int em28xx_vol_put(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *value)
	{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) \|
	(0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
	int rc;

	mutex_lock(&dev->lock);
	rc = em28xx_read_ac97(dev, kcontrol->private_value);
	if (rc < 0)
	goto err;

	val \|= rc & 0x8000; /* Preserve the mute flag */

	rc = em28xx_write_ac97(dev, kcontrol->private_value, val);
	if (rc < 0)
	goto err;

	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
	(val & 0x8000) ? "muted " : "",
	0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
	val, (int)kcontrol->private_value);

	err:
	mutex_unlock(&dev->lock);
	return rc;
	}

	static int em28xx_vol_get(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *value)
	{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	int val;

	mutex_lock(&dev->lock);
	val = em28xx_read_ac97(dev, kcontrol->private_value);
	mutex_unlock(&dev->lock);
	if (val < 0)
	return val;

	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
	(val & 0x8000) ? "muted " : "",
	0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
	val, (int)kcontrol->private_value);

	value->value.integer.value[0] = 0x1f - (val & 0x1f);
	value->value.integer.value[1] = 0x1f - ((val << 8) & 0x1f);

	return 0;
	}

	static int em28xx_vol_put_mute(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *value)
	{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	u16 val = value->value.integer.value[0];
	int rc;

	mutex_lock(&dev->lock);
	rc = em28xx_read_ac97(dev, kcontrol->private_value);
	if (rc < 0)
	goto err;

	if (val)
	rc &= 0x1f1f;
	else
	rc \|= 0x8000;

	rc = em28xx_write_ac97(dev, kcontrol->private_value, rc);
	if (rc < 0)
	goto err;

	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
	(val & 0x8000) ? "muted " : "",
	0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
	val, (int)kcontrol->private_value);

	err:
	mutex_unlock(&dev->lock);
	return rc;
	}

	static int em28xx_vol_get_mute(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *value)
	{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	int val;

	mutex_lock(&dev->lock);
	val = em28xx_read_ac97(dev, kcontrol->private_value);
	mutex_unlock(&dev->lock);
	if (val < 0)
	return val;

	if (val & 0x8000)
	value->value.integer.value[0] = 0;
	else
	value->value.integer.value[0] = 1;

	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
	(val & 0x8000) ? "muted " : "",
	0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
	val, (int)kcontrol->private_value);

	return 0;
	}

	static const DECLARE_TLV_DB_SCALE(em28xx_db_scale, -3450, 150, 0);

	static int em28xx_cvol_new(struct snd_card card, struct em28xx dev,
	char *name, int id)
	{
	int err;
	char ctl_name[44];
	struct snd_kcontrol *kctl;
	struct snd_kcontrol_new tmp;

	memset (&tmp, 0, sizeof(tmp));
	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	tmp.private_value = id,
	tmp.name = ctl_name,

	/* Add Mute Control */
	sprintf(ctl_name, "%s Switch", name);
	tmp.get = em28xx_vol_get_mute;
	tmp.put = em28xx_vol_put_mute;
	tmp.info = snd_ctl_boolean_mono_info;
	kctl = snd_ctl_new1(&tmp, dev);
	err = snd_ctl_add(card, kctl);
	if (err < 0)
	return err;
	dprintk("Added control %s for ac97 volume control 0x%04x\n",
	ctl_name, id);

	memset (&tmp, 0, sizeof(tmp));
	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	tmp.private_value = id,
	tmp.name = ctl_name,

	/* Add Volume Control */
	sprintf(ctl_name, "%s Volume", name);
	tmp.get = em28xx_vol_get;
	tmp.put = em28xx_vol_put;
	tmp.info = em28xx_vol_info;
	tmp.tlv.p = em28xx_db_scale,
	kctl = snd_ctl_new1(&tmp, dev);
	err = snd_ctl_add(card, kctl);
	if (err < 0)
	return err;
	dprintk("Added control %s for ac97 volume control 0x%04x\n",
	ctl_name, id);

	return 0;
	}

	/*
	* register/unregister code and data
	*/
	static struct snd_pcm_ops snd_em28xx_pcm_capture = {
	.open = snd_em28xx_capture_open,
	.close = snd_em28xx_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = snd_em28xx_hw_capture_params,
	.hw_free = snd_em28xx_hw_capture_free,
	.prepare = snd_em28xx_prepare,
	.trigger = snd_em28xx_capture_trigger,
	.pointer = snd_em28xx_capture_pointer,
	.page = snd_pcm_get_vmalloc_page,
	};

	static int em28xx_audio_init(struct em28xx *dev)
	{
	struct em28xx_audio *adev = &dev->adev;
	struct snd_pcm *pcm;
	struct snd_card *card;
	static int devnr;
	int err;

	if (!dev->has_alsa_audio \|\| dev->audio_ifnum < 0) {
	/* This device does not support the extension (in this case
	the device is expecting the snd-usb-audio module or
	doesn't have analog audio support at all) */
	return 0;
	}

	printk(KERN_INFO "em28xx-audio.c: probing for em28xx Audio Vendor Class\n");
	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
	"Rechberger\n");
	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2007-2011 Mauro Carvalho Chehab\n");

	err = snd_card_create(index[devnr], "Em28xx Audio", THIS_MODULE, 0,
	&card);
	if (err < 0)
	return err;

	spin_lock_init(&adev->slock);
	err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
	if (err < 0) {
	snd_card_free(card);
	return err;
	}

	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
	pcm->info_flags = 0;
	pcm->private_data = dev;
	strcpy(pcm->name, "Empia 28xx Capture");

	snd_card_set_dev(card, &dev->udev->dev);
	strcpy(card->driver, "Em28xx-Audio");
	strcpy(card->shortname, "Em28xx Audio");
	strcpy(card->longname, "Empia Em28xx Audio");

	INIT_WORK(&dev->wq_trigger, audio_trigger);

	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
	em28xx_cvol_new(card, dev, "Video", AC97_VIDEO);
	em28xx_cvol_new(card, dev, "Line In", AC97_LINE);
	em28xx_cvol_new(card, dev, "Phone", AC97_PHONE);
	em28xx_cvol_new(card, dev, "Microphone", AC97_MIC);
	em28xx_cvol_new(card, dev, "CD", AC97_CD);
	em28xx_cvol_new(card, dev, "AUX", AC97_AUX);
	em28xx_cvol_new(card, dev, "PCM", AC97_PCM);

	em28xx_cvol_new(card, dev, "Master", AC97_MASTER);
	em28xx_cvol_new(card, dev, "Line", AC97_HEADPHONE);
	em28xx_cvol_new(card, dev, "Mono", AC97_MASTER_MONO);
	em28xx_cvol_new(card, dev, "LFE", AC97_CENTER_LFE_MASTER);
	em28xx_cvol_new(card, dev, "Surround", AC97_SURROUND_MASTER);
	}

	err = snd_card_register(card);
	if (err < 0) {
	snd_card_free(card);
	return err;
	}
	adev->sndcard = card;
	adev->udev = dev->udev;

	return 0;
	}

	static int em28xx_audio_fini(struct em28xx *dev)
	{
	if (dev == NULL)
	return 0;

	if (dev->has_alsa_audio != 1) {
	/* This device does not support the extension (in this case
	the device is expecting the snd-usb-audio module or
	doesn't have analog audio support at all) */
	return 0;
	}

	if (dev->adev.sndcard) {
	snd_card_free(dev->adev.sndcard);
	dev->adev.sndcard = NULL;
	}

	return 0;
	}

	static struct em28xx_ops audio_ops = {
	.id = EM28XX_AUDIO,
	.name = "Em28xx Audio Extension",
	.init = em28xx_audio_init,
	.fini = em28xx_audio_fini,
	};

	static int __init em28xx_alsa_register(void)
	{
	return em28xx_register_extension(&audio_ops);
	}

	static void __exit em28xx_alsa_unregister(void)
	{
	em28xx_unregister_extension(&audio_ops);
	}

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Markus Rechberger <mrechberger@gmail.com>");
	MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
	MODULE_DESCRIPTION("Em28xx Audio driver");

	module_init(em28xx_alsa_register);
	module_exit(em28xx_alsa_unregister);