1 files changed, 751 insertions, 0 deletions

diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c
new file mode 100644
index 000000000000..2fdb66ee44ab
--- /dev/null
+++ b/drivers/media/usb/em28xx/em28xx-audio.c
@@ -0,0 +1,751 @@
+/*
+ *  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);