text: /*
   *  Empiatech em28x1 audio extension
   *
   *  Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
   *
   *  Copyright (C) 2007-2014 Mauro Carvalho Chehab
   *	- 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 EM28XX_MAX_AUDIO_BUFS		5
  #define EM28XX_MIN_AUDIO_PACKETS	64
  
  #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 < dev->adev.num_urb; i++) {
  		struct urb *urb = dev->adev.urb[i];
  
  		if (!irqs_disabled())
  			usb_kill_urb(urb);
  		else
  			usb_unlink_urb(urb);
  	}
  
  	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;
  
  	if (dev->disconnected) {
  		dprintk("device disconnected while streaming. URB status=%d.\n", urb->status);
  		atomic_set(&dev->adev.stream_started, 0);
  		return;
  	}
  
  	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->adev.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;
  
  	dprintk("Starting isoc transfers\n");
  
  	/* Start streaming */
  	for (i = 0; i < dev->adev.num_urb; i++) {
  		memset(dev->adev.transfer_buffer[i], 0x80,
  		       dev->adev.urb[i]->transfer_buffer_length);
  
  		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
  		if (errCode) {
  			em28xx_errdev("submit of audio urb failed (error=%i)\n",
  				      errCode);
  			em28xx_deinit_isoc_audio(dev);
  			atomic_set(&dev->adev.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_48000,
  
  	.rate_min = 48000,
  	.rate_max = 48000,
  	.channels_min = 2,
  	.channels_max = 2,
  	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
  
  	/*
  	 * The period is 12.288 bytes. Allow a 10% of variation along its
  	 * value, in order to avoid overruns/underruns due to some clock
  	 * drift.
  	 *
  	 * FIXME: This period assumes 64 packets, and a 48000 PCM rate.
  	 * Calculate it dynamically.
  	 */
  	.period_bytes_min = 11059,
  	.period_bytes_max = 13516,
  
  	.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 nonblock, ret = 0;
  
  	if (!dev) {
  		em28xx_err("BUG: em28xx can't find device struct."
  				" Can't proceed with open\n");
  		return -ENODEV;
  	}
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	dprintk("opening device and trying to acquire exclusive lock\n");
  
  	nonblock = !!(substream->f_flags & O_NONBLOCK);
  	if (nonblock) {
  		if (!mutex_trylock(&dev->lock))
  			return -EAGAIN;
  	} else
  		mutex_lock(&dev->lock);
  
  	runtime->hw = snd_em28xx_hw_capture;
  
  	if (dev->adev.users == 0) {
  		if (dev->alt == 0 || dev->is_audio_only) {
  			if (dev->is_audio_only)
  				/* audio is on a separate interface */
  				dev->alt = 1;
  			else
  				/* audio is on the same interface as video */
  				dev->alt = 7;
  				/*
  				 * FIXME: The intention seems to be to select
  				 * the alt setting with the largest
  				 * wMaxPacketSize for the video endpoint.
  				 * At least dev->alt should be used instead, but
  				 * we should probably not touch it at all if it
  				 * is already >0, because wMaxPacketSize of the
  				 * audio endpoints seems to be the same for all.
  				 */
  			dprintk("changing alternate number on interface %d to %d\n",
  				dev->ifnum, dev->alt);
  			usb_set_interface(dev->udev, dev->ifnum, dev->alt);
  		}
  
  		/* Sets volume, mute, etc */
  		dev->mute = 0;
  		ret = em28xx_audio_analog_set(dev);
  		if (ret < 0)
  			goto err;
  	}
  
  	kref_get(&dev->ref);
  	dev->adev.users++;
  	mutex_unlock(&dev->lock);
  
  	/* Dynamically adjust the period size */
  	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
  	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
  				     dev->adev.period * 95 / 100,
  				     dev->adev.period * 105 / 100);
  
  	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->adev.stream_started) > 0) {
  		atomic_set(&dev->adev.stream_started, 0);
  		schedule_work(&dev->adev.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);
  	kref_put(&dev->ref, em28xx_free_device);
  
  	return 0;
  }
  
  static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream,
  					struct snd_pcm_hw_params *hw_params)
  {
  	int ret;
  	struct em28xx *dev = snd_pcm_substream_chip(substream);
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	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);
  	struct em28xx_audio *adev = &dev->adev;
  
  	dprintk("Stop capture, if needed\n");
  
  	if (atomic_read(&adev->stream_started) > 0) {
  		atomic_set(&adev->stream_started, 0);
  		schedule_work(&adev->wq_trigger);
  	}
  
  	return 0;
  }
  
  static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
  {
  	struct em28xx *dev = snd_pcm_substream_chip(substream);
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	dev->adev.hwptr_done_capture = 0;
  	dev->adev.capture_transfer_done = 0;
  
  	return 0;
  }
  
  static void audio_trigger(struct work_struct *work)
  {
  	struct em28xx_audio *adev =
  			    container_of(work, struct em28xx_audio, wq_trigger);
  	struct em28xx *dev = container_of(adev, struct em28xx, adev);
  
  	if (atomic_read(&adev->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;
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	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->adev.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->adev.stream_started, 0);
  		break;
  	default:
  		retval = -EINVAL;
  	}
  	schedule_work(&dev->adev.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);
  	if (dev->disconnected)
  		return SNDRV_PCM_POS_XRUN;
  
  	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)
  {
  	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	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);
  	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
  	u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) |
  		  (0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
  	int nonblock = 0;
  	int rc;
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	if (substream)
  		nonblock = !!(substream->f_flags & O_NONBLOCK);
  	if (nonblock) {
  		if (!mutex_trylock(&dev->lock))
  			return -EAGAIN;
  	} else
  		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);
  	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
  	int nonblock = 0;
  	int val;
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	if (substream)
  		nonblock = !!(substream->f_flags & O_NONBLOCK);
  	if (nonblock) {
  		if (!mutex_trylock(&dev->lock))
  			return -EAGAIN;
  	} else
  		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];
  	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
  	int nonblock = 0;
  	int rc;
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	if (substream)
  		nonblock = !!(substream->f_flags & O_NONBLOCK);
  	if (nonblock) {
  		if (!mutex_trylock(&dev->lock))
  			return -EAGAIN;
  	} else
  		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);
  	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
  	int nonblock = 0;
  	int val;
  
  	if (dev->disconnected)
  		return -ENODEV;
  
  	if (substream)
  		nonblock = !!(substream->f_flags & O_NONBLOCK);
  	if (nonblock) {
  		if (!mutex_trylock(&dev->lock))
  			return -EAGAIN;
  	} else
  		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 void em28xx_audio_free_urb(struct em28xx *dev)
  {
  	int i;
  
  	for (i = 0; i < dev->adev.num_urb; i++) {
  		struct urb *urb = dev->adev.urb[i];
  
  		if (!urb)
  			continue;
  
  		usb_free_coherent(dev->udev, urb->transfer_buffer_length,
  				  dev->adev.transfer_buffer[i],
  				  urb->transfer_dma);
  
  		usb_free_urb(urb);
  	}
  	kfree(dev->adev.urb);
  	kfree(dev->adev.transfer_buffer);
  	dev->adev.num_urb = 0;
  }
  
  /* high bandwidth multiplier, as encoded in highspeed endpoint descriptors */
  static int em28xx_audio_ep_packet_size(struct usb_device *udev,
  				       struct usb_endpoint_descriptor *e)
  {
  	int size = le16_to_cpu(e->wMaxPacketSize);
  
  	if (udev->speed == USB_SPEED_HIGH)
  		return (size & 0x7ff) *  (1 + (((size) >> 11) & 0x03));
  
  	return size & 0x7ff;
  }
  
  static int em28xx_audio_urb_init(struct em28xx *dev)
  {
  	struct usb_interface *intf;
  	struct usb_endpoint_descriptor *e, *ep = NULL;
  	int                 i, ep_size, interval, num_urb, npackets;
  	int		    urb_size, bytes_per_transfer;
  	u8 alt;
  
  	if (dev->ifnum)
  		alt = 1;
  	else
  		alt = 7;
  
  	intf = usb_ifnum_to_if(dev->udev, dev->ifnum);
  
  	if (intf->num_altsetting <= alt) {
  		em28xx_errdev("alt %d doesn't exist on interface %d\n",
  			      dev->ifnum, alt);
  		return -ENODEV;
  	}
  
  	for (i = 0; i < intf->altsetting[alt].desc.bNumEndpoints; i++) {
  		e = &intf->altsetting[alt].endpoint[i].desc;
  		if (!usb_endpoint_dir_in(e))
  			continue;
  		if (e->bEndpointAddress == EM28XX_EP_AUDIO) {
  			ep = e;
  			break;
  		}
  	}
  
  	if (!ep) {
  		em28xx_errdev("Couldn't find an audio endpoint");
  		return -ENODEV;
  	}
  
  	ep_size = em28xx_audio_ep_packet_size(dev->udev, ep);
  	interval = 1 << (ep->bInterval - 1);
  
  	em28xx_info("Endpoint 0x%02x %s on intf %d alt %d interval = %d, size %d\n",
  		    EM28XX_EP_AUDIO, usb_speed_string(dev->udev->speed),
  		     dev->ifnum, alt,
  		     interval,
  		     ep_size);
  
  	/* Calculate the number and size of URBs to better fit the audio samples */
  
  	/*
  	 * Estimate the number of bytes per DMA transfer.
  	 *
  	 * This is given by the bit rate (for now, only 48000 Hz) multiplied
  	 * by 2 channels and 2 bytes/sample divided by the number of microframe
  	 * intervals and by the microframe rate (125 us)
  	 */
  	bytes_per_transfer = DIV_ROUND_UP(48000 * 2 * 2, 125 * interval);
  
  	/*
  	 * Estimate the number of transfer URBs. Don't let it go past the
  	 * maximum number of URBs that is known to be supported by the device.
  	 */
  	num_urb = DIV_ROUND_UP(bytes_per_transfer, ep_size);
  	if (num_urb > EM28XX_MAX_AUDIO_BUFS)
  		num_urb = EM28XX_MAX_AUDIO_BUFS;
  
  	/*
  	 * Now that we know the number of bytes per transfer and the number of
  	 * URBs, estimate the typical size of an URB, in order to adjust the
  	 * minimal number of packets.
  	 */
  	urb_size = bytes_per_transfer / num_urb;
  
  	/*
  	 * Now, calculate the amount of audio packets to be filled on each
  	 * URB. In order to preserve the old behaviour, use a minimal
  	 * threshold for this value.
  	 */
  	npackets = EM28XX_MIN_AUDIO_PACKETS;
  	if (urb_size > ep_size * npackets)
  		npackets = DIV_ROUND_UP(urb_size, ep_size);
  
  	em28xx_info("Number of URBs: %d, with %d packets and %d size",
  		    num_urb, npackets, urb_size);
  
  	/* Estimate the bytes per period */
  	dev->adev.period = urb_size * npackets;
  
  	/* Allocate space to store the number of URBs to be used */
  
  	dev->adev.transfer_buffer = kcalloc(num_urb,
  					    sizeof(*dev->adev.transfer_buffer),
  					    GFP_ATOMIC);
  	if (!dev->adev.transfer_buffer) {
  		return -ENOMEM;
  	}
  
  	dev->adev.urb = kcalloc(num_urb, sizeof(*dev->adev.urb), GFP_ATOMIC);
  	if (!dev->adev.urb) {
  		kfree(dev->adev.transfer_buffer);
  		return -ENOMEM;
  	}
  
  	/* Alloc memory for each URB and for each transfer buffer */
  	dev->adev.num_urb = num_urb;
  	for (i = 0; i < num_urb; i++) {
  		struct urb *urb;
  		int j, k;
  		void *buf;
  
  		urb = usb_alloc_urb(npackets, GFP_ATOMIC);
  		if (!urb) {
  			em28xx_errdev("usb_alloc_urb failed!\n");
  			em28xx_audio_free_urb(dev);
  			return -ENOMEM;
  		}
  		dev->adev.urb[i] = urb;
  
  		buf = usb_alloc_coherent(dev->udev, npackets * ep_size, GFP_ATOMIC,
  					 &urb->transfer_dma);
  		if (!buf) {
  			em28xx_errdev("usb_alloc_coherent failed!\n");
  			em28xx_audio_free_urb(dev);
  			return -ENOMEM;
  		}
  		dev->adev.transfer_buffer[i] = buf;
  
  		urb->dev = dev->udev;
  		urb->context = dev;
  		urb->pipe = usb_rcvisocpipe(dev->udev, EM28XX_EP_AUDIO);
  		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
  		urb->transfer_buffer = buf;
  		urb->interval = interval;
  		urb->complete = em28xx_audio_isocirq;
  		urb->number_of_packets = npackets;
  		urb->transfer_buffer_length = ep_size * npackets;
  
  		for (j = k = 0; j < npackets; j++, k += ep_size) {
  			urb->iso_frame_desc[j].offset = k;
  			urb->iso_frame_desc[j].length = ep_size;
  		}
  	}
  
  	return 0;
  }
  
  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->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
  		/* 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;
  	}
  
  	em28xx_info("Binding audio extension\n");
  
  	kref_get(&dev->ref);
  
  	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
  			 "Rechberger\n");
  	printk(KERN_INFO
  	       "em28xx-audio.c: Copyright (C) 2007-2014 Mauro Carvalho Chehab\n");
  
  	err = snd_card_new(&dev->udev->dev, index[devnr], "Em28xx Audio",
  			   THIS_MODULE, 0, &card);
  	if (err < 0)
  		return err;
  
  	spin_lock_init(&adev->slock);
  	adev->sndcard = card;
  	adev->udev = dev->udev;
  
  	err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
  	if (err < 0)
  		goto card_free;
  
  	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");
  
  	strcpy(card->driver, "Em28xx-Audio");
  	strcpy(card->shortname, "Em28xx Audio");
  	strcpy(card->longname, "Empia Em28xx Audio");
  
  	INIT_WORK(&adev->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 = em28xx_audio_urb_init(dev);
  	if (err)
  		goto card_free;
  
  	err = snd_card_register(card);
  	if (err < 0)
  		goto urb_free;
  
  	em28xx_info("Audio extension successfully initialized\n");
  	return 0;
  
  urb_free:
  	em28xx_audio_free_urb(dev);
  
  card_free:
  	snd_card_free(card);
  	adev->sndcard = NULL;
  
  	return err;
  }
  
  static int em28xx_audio_fini(struct em28xx *dev)
  {
  	if (dev == NULL)
  		return 0;
  
  	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
  		/* 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;
  	}
  
  	em28xx_info("Closing audio extension");
  
  	if (dev->adev.sndcard) {
  		snd_card_disconnect(dev->adev.sndcard);
  		flush_work(&dev->adev.wq_trigger);
  
  		em28xx_audio_free_urb(dev);
  
  		snd_card_free(dev->adev.sndcard);
  		dev->adev.sndcard = NULL;
  	}
  
  	kref_put(&dev->ref, em28xx_free_device);
  	return 0;
  }
  
  static int em28xx_audio_suspend(struct em28xx *dev)
  {
  	if (dev == NULL)
  		return 0;
  
  	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
  		return 0;
  
  	em28xx_info("Suspending audio extension");
  	em28xx_deinit_isoc_audio(dev);
  	atomic_set(&dev->adev.stream_started, 0);
  	return 0;
  }
  
  static int em28xx_audio_resume(struct em28xx *dev)
  {
  	if (dev == NULL)
  		return 0;
  
  	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
  		return 0;
  
  	em28xx_info("Resuming audio extension");
  	/* Nothing to do other than schedule_work() ?? */
  	schedule_work(&dev->adev.wq_trigger);
  	return 0;
  }
  
  static struct em28xx_ops audio_ops = {
  	.id   = EM28XX_AUDIO,
  	.name = "Em28xx Audio Extension",
  	.init = em28xx_audio_init,
  	.fini = em28xx_audio_fini,
  	.suspend = em28xx_audio_suspend,
  	.resume = em28xx_audio_resume,
  };
  
  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");
  MODULE_DESCRIPTION(DRIVER_DESC " - audio interface");
  MODULE_VERSION(EM28XX_VERSION);
  
  module_init(em28xx_alsa_register);
  module_exit(em28xx_alsa_unregister);
  