text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   *   Tascam US-16x08 ALSA driver
   *
   *   Copyright (c) 2016 by Detlef Urban (onkel@paraair.de)
   */
  
  #include <linux/slab.h>
  #include <linux/usb.h>
  #include <linux/usb/audio-v2.h>
  
  #include <sound/core.h>
  #include <sound/control.h>
  
  #include "usbaudio.h"
  #include "mixer.h"
  #include "helper.h"
  
  #include "mixer_us16x08.h"
  
  /* USB control message templates */
  static const char route_msg[] = {
  	0x61,
  	0x02,
  	0x03, /* input from master (0x02) or input from computer bus (0x03) */
  	0x62,
  	0x02,
  	0x01, /* input index (0x01/0x02 eq. left/right) or bus (0x01-0x08) */
  	0x41,
  	0x01,
  	0x61,
  	0x02,
  	0x01,
  	0x62,
  	0x02,
  	0x01, /* output index (0x01-0x08) */
  	0x42,
  	0x01,
  	0x43,
  	0x01,
  	0x00,
  	0x00
  };
  
  static const char mix_init_msg1[] = {
  	0x71, 0x01, 0x00, 0x00
  };
  
  static const char mix_init_msg2[] = {
  	0x62, 0x02, 0x00, 0x61, 0x02, 0x04, 0xb1, 0x01, 0x00, 0x00
  };
  
  static const char mix_msg_in[] = {
  	/* default message head, equal to all mixers */
  	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
  	0x81, /* 0x06: Controller ID */
  	0x02, /* 0x07:  */
  	0x00, /* 0x08: Value of common mixer */
  	0x00,
  	0x00
  };
  
  static const char mix_msg_out[] = {
  	/* default message head, equal to all mixers */
  	0x61, 0x02, 0x02, 0x62, 0x02, 0x01,
  	0x81, /* 0x06: Controller ID */
  	0x02, /*                    0x07:  */
  	0x00, /*                    0x08: Value of common mixer */
  	0x00,
  	0x00
  };
  
  static const char bypass_msg_out[] = {
  	0x45,
  	0x02,
  	0x01, /* on/off flag */
  	0x00,
  	0x00
  };
  
  static const char bus_msg_out[] = {
  	0x44,
  	0x02,
  	0x01, /* on/off flag */
  	0x00,
  	0x00
  };
  
  static const char comp_msg[] = {
  	/* default message head, equal to all mixers */
  	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
  	0x91,
  	0x02,
  	0xf0, /* 0x08: Threshold db (8) (e0 ... 00) (+-0dB -- -32dB) x-32 */
  	0x92,
  	0x02,
  	0x0a, /* 0x0b: Ratio (0a,0b,0d,0f,11,14,19,1e,23,28,32,3c,50,a0,ff)  */
  	0x93,
  	0x02,
  	0x02, /* 0x0e: Attack (0x02 ... 0xc0) (2ms ... 200ms) */
  	0x94,
  	0x02,
  	0x01, /* 0x11: Release (0x01 ... 0x64) (10ms ... 1000ms) x*10  */
  	0x95,
  	0x02,
  	0x03, /* 0x14: gain (0 ... 20) (0dB .. 20dB) */
  	0x96,
  	0x02,
  	0x01,
  	0x97,
  	0x02,
  	0x01, /* 0x1a: main Comp switch (0 ... 1) (off ... on)) */
  	0x00,
  	0x00
  };
  
  static const char eqs_msq[] = {
  	/* default message head, equal to all mixers */
  	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
  	0x51, /*                0x06: Controller ID  */
  	0x02,
  	0x04, /* 0x08: EQ set num (0x01..0x04) (LOW, LOWMID, HIGHMID, HIGH)) */
  	0x52,
  	0x02,
  	0x0c, /* 0x0b: value dB (0 ... 12) (-12db .. +12db)  x-6 */
  	0x53,
  	0x02,
  	0x0f, /* 0x0e: value freq (32-47) (1.7kHz..18kHz) */
  	0x54,
  	0x02,
  	0x02, /* 0x11: band width (0-6) (Q16-Q0.25)  2^x/4 (EQ xxMID only) */
  	0x55,
  	0x02,
  	0x01, /* 0x14: main EQ switch (0 ... 1) (off ... on)) */
  	0x00,
  	0x00
  };
  
  /* compressor ratio map */
  static const char ratio_map[] = {
  	0x0a, 0x0b, 0x0d, 0x0f, 0x11, 0x14, 0x19, 0x1e,
  	0x23, 0x28, 0x32, 0x3c, 0x50, 0xa0, 0xff
  };
  
  /* route enumeration names */
  static const char *const route_names[] = {
  	"Master Left", "Master Right", "Output 1", "Output 2", "Output 3",
  	"Output 4", "Output 5", "Output 6", "Output 7", "Output 8",
  };
  
  static int snd_us16x08_recv_urb(struct snd_usb_audio *chip,
  	unsigned char *buf, int size)
  {
  
  	mutex_lock(&chip->mutex);
  	snd_usb_ctl_msg(chip->dev,
  		usb_rcvctrlpipe(chip->dev, 0),
  		SND_US16X08_URB_METER_REQUEST,
  		SND_US16X08_URB_METER_REQUESTTYPE, 0, 0, buf, size);
  	mutex_unlock(&chip->mutex);
  	return 0;
  }
  
  /* wrapper function to send prepared URB buffer to usb device. Return an error
   * code if something went wrong
   */
  static int snd_us16x08_send_urb(struct snd_usb_audio *chip, char *buf, int size)
  {
  	return snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
  			SND_US16X08_URB_REQUEST, SND_US16X08_URB_REQUESTTYPE,
  			0, 0, buf, size);
  }
  
  static int snd_us16x08_route_info(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_info *uinfo)
  {
  	return snd_ctl_enum_info(uinfo, 1, 10, route_names);
  }
  
  static int snd_us16x08_route_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	int index = ucontrol->id.index;
  
  	/* route has no bias */
  	ucontrol->value.enumerated.item[0] = elem->cache_val[index];
  
  	return 0;
  }
  
  static int snd_us16x08_route_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	int index = ucontrol->id.index;
  	char buf[sizeof(route_msg)];
  	int val, val_org, err;
  
  	/*  get the new value (no bias for routes) */
  	val = ucontrol->value.enumerated.item[0];
  
  	/* sanity check */
  	if (val < 0 || val > 9)
  		return -EINVAL;
  
  	/* prepare the message buffer from template */
  	memcpy(buf, route_msg, sizeof(route_msg));
  
  	if (val < 2) {
  		/* input comes from a master channel */
  		val_org = val;
  		buf[2] = 0x02;
  	} else {
  		/* input comes from a computer channel */
  		buf[2] = 0x03;
  		val_org = val - 2;
  	}
  
  	/* place new route selection in URB message */
  	buf[5] = (unsigned char) (val_org & 0x0f) + 1;
  	/* place route selector in URB message */
  	buf[13] = index + 1;
  
  	err = snd_us16x08_send_urb(chip, buf, sizeof(route_msg));
  
  	if (err > 0) {
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set routing, err:%d\n", err);
  	}
  
  	return err > 0 ? 1 : 0;
  }
  
  static int snd_us16x08_master_info(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_info *uinfo)
  {
  	uinfo->count = 1;
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
  	uinfo->value.integer.max = SND_US16X08_KCMAX(kcontrol);
  	uinfo->value.integer.min = SND_US16X08_KCMIN(kcontrol);
  	uinfo->value.integer.step = SND_US16X08_KCSTEP(kcontrol);
  	return 0;
  }
  
  static int snd_us16x08_master_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	int index = ucontrol->id.index;
  
  	ucontrol->value.integer.value[0] = elem->cache_val[index];
  
  	return 0;
  }
  
  static int snd_us16x08_master_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	char buf[sizeof(mix_msg_out)];
  	int val, err;
  	int index = ucontrol->id.index;
  
  	/* new control value incl. bias*/
  	val = ucontrol->value.integer.value[0];
  
  	/* sanity check */
  	if (val < SND_US16X08_KCMIN(kcontrol)
  		|| val > SND_US16X08_KCMAX(kcontrol))
  		return -EINVAL;
  
  	/* prepare the message buffer from template */
  	memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
  
  	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
  	buf[6] = elem->head.id;
  
  	/* place channel selector in URB message */
  	buf[5] = index + 1;
  	err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_out));
  
  	if (err > 0) {
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set master, err:%d\n", err);
  	}
  
  	return err > 0 ? 1 : 0;
  }
  
  static int snd_us16x08_bus_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	char buf[sizeof(mix_msg_out)];
  	int val, err = 0;
  
  	val = ucontrol->value.integer.value[0];
  
  	/* prepare the message buffer from template */
  	switch (elem->head.id) {
  	case SND_US16X08_ID_BYPASS:
  		memcpy(buf, bypass_msg_out, sizeof(bypass_msg_out));
  		buf[2] = val;
  		err = snd_us16x08_send_urb(chip, buf, sizeof(bypass_msg_out));
  		break;
  	case SND_US16X08_ID_BUSS_OUT:
  		memcpy(buf, bus_msg_out, sizeof(bus_msg_out));
  		buf[2] = val;
  		err = snd_us16x08_send_urb(chip, buf, sizeof(bus_msg_out));
  		break;
  	case SND_US16X08_ID_MUTE:
  		memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
  		buf[8] = val;
  		buf[6] = elem->head.id;
  		buf[5] = 1;
  		err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_out));
  		break;
  	}
  
  	if (err > 0) {
  		elem->cached |= 1;
  		elem->cache_val[0] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set bus parameter, err:%d\n", err);
  	}
  
  	return err > 0 ? 1 : 0;
  }
  
  static int snd_us16x08_bus_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  
  	switch (elem->head.id) {
  	case SND_US16X08_ID_BUSS_OUT:
  		ucontrol->value.integer.value[0] = elem->cache_val[0];
  		break;
  	case SND_US16X08_ID_BYPASS:
  		ucontrol->value.integer.value[0] = elem->cache_val[0];
  		break;
  	case SND_US16X08_ID_MUTE:
  		ucontrol->value.integer.value[0] = elem->cache_val[0];
  		break;
  	}
  
  	return 0;
  }
  
  /* gets a current mixer value from common store */
  static int snd_us16x08_channel_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	int index = ucontrol->id.index;
  
  	ucontrol->value.integer.value[0] = elem->cache_val[index];
  
  	return 0;
  }
  
  static int snd_us16x08_channel_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	char buf[sizeof(mix_msg_in)];
  	int val, err;
  	int index = ucontrol->id.index;
  
  	val = ucontrol->value.integer.value[0];
  
  	/* sanity check */
  	if (val < SND_US16X08_KCMIN(kcontrol)
  		|| val > SND_US16X08_KCMAX(kcontrol))
  		return -EINVAL;
  
  	/* prepare URB message from template */
  	memcpy(buf, mix_msg_in, sizeof(mix_msg_in));
  
  	/* add the bias to the new value */
  	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
  	buf[6] = elem->head.id;
  	buf[5] = index + 1;
  
  	err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_in));
  
  	if (err > 0) {
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set channel, err:%d\n", err);
  	}
  
  	return err > 0 ? 1 : 0;
  }
  
  static int snd_us16x08_mix_info(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_info *uinfo)
  {
  	uinfo->count = 1;
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
  	uinfo->value.integer.max = SND_US16X08_KCMAX(kcontrol);
  	uinfo->value.integer.min = SND_US16X08_KCMIN(kcontrol);
  	uinfo->value.integer.step = SND_US16X08_KCSTEP(kcontrol);
  	return 0;
  }
  
  static int snd_us16x08_comp_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_us16x08_comp_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  	int val_idx = COMP_STORE_IDX(elem->head.id);
  
  	ucontrol->value.integer.value[0] = store->val[val_idx][index];
  
  	return 0;
  }
  
  static int snd_us16x08_comp_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	struct snd_us16x08_comp_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  	char buf[sizeof(comp_msg)];
  	int val_idx, val;
  	int err;
  
  	val = ucontrol->value.integer.value[0];
  
  	/* sanity check */
  	if (val < SND_US16X08_KCMIN(kcontrol)
  		|| val > SND_US16X08_KCMAX(kcontrol))
  		return -EINVAL;
  
  	/* new control value incl. bias*/
  	val_idx = elem->head.id - SND_US16X08_ID_COMP_BASE;
  
  	store->val[val_idx][index] = ucontrol->value.integer.value[0];
  
  	/* prepare compressor URB message from template  */
  	memcpy(buf, comp_msg, sizeof(comp_msg));
  
  	/* place comp values in message buffer watch bias! */
  	buf[8] = store->val[
  		COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD)][index]
  		- SND_US16X08_COMP_THRESHOLD_BIAS;
  	buf[11] = ratio_map[store->val[
  		COMP_STORE_IDX(SND_US16X08_ID_COMP_RATIO)][index]];
  	buf[14] = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_ATTACK)][index]
  		+ SND_US16X08_COMP_ATTACK_BIAS;
  	buf[17] = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RELEASE)][index]
  		+ SND_US16X08_COMP_RELEASE_BIAS;
  	buf[20] = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_GAIN)][index];
  	buf[26] = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)][index];
  
  	/* place channel selector in message buffer */
  	buf[5] = index + 1;
  
  	err = snd_us16x08_send_urb(chip, buf, sizeof(comp_msg));
  
  	if (err > 0) {
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set compressor, err:%d\n", err);
  	}
  
  	return 1;
  }
  
  static int snd_us16x08_eqswitch_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	int val;
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_us16x08_eq_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  
  	/* get low switch from cache is enough, cause all bands are together */
  	val = store->val[EQ_STORE_BAND_IDX(elem->head.id)]
  		[EQ_STORE_PARAM_IDX(elem->head.id)][index];
  	ucontrol->value.integer.value[0] = val;
  
  	return 0;
  }
  
  static int snd_us16x08_eqswitch_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	struct snd_us16x08_eq_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  	char buf[sizeof(eqs_msq)];
  	int val, err = 0;
  	int b_idx;
  
  	/* new control value incl. bias*/
  	val = ucontrol->value.integer.value[0] + SND_US16X08_KCBIAS(kcontrol);
  
  	/* prepare URB message from EQ template */
  	memcpy(buf, eqs_msq, sizeof(eqs_msq));
  
  	/* place channel index in URB message */
  	buf[5] = index + 1;
  	for (b_idx = 0; b_idx < SND_US16X08_ID_EQ_BAND_COUNT; b_idx++) {
  		/* all four EQ bands have to be enabled/disabled in once */
  		buf[20] = val;
  		buf[17] = store->val[b_idx][2][index];
  		buf[14] = store->val[b_idx][1][index];
  		buf[11] = store->val[b_idx][0][index];
  		buf[8] = b_idx + 1;
  		err = snd_us16x08_send_urb(chip, buf, sizeof(eqs_msq));
  		if (err < 0)
  			break;
  		store->val[b_idx][3][index] = val;
  		msleep(15);
  	}
  
  	if (err > 0) {
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set eq switch, err:%d\n", err);
  	}
  
  	return 1;
  }
  
  static int snd_us16x08_eq_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	int val;
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_us16x08_eq_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
  	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
  
  	val = store->val[b_idx][p_idx][index];
  
  	ucontrol->value.integer.value[0] = val;
  
  	return 0;
  }
  
  static int snd_us16x08_eq_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	struct snd_us16x08_eq_store *store = elem->private_data;
  	int index = ucontrol->id.index;
  	char buf[sizeof(eqs_msq)];
  	int val, err;
  	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
  	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
  
  	val = ucontrol->value.integer.value[0];
  
  	/* sanity check */
  	if (val < SND_US16X08_KCMIN(kcontrol)
  		|| val > SND_US16X08_KCMAX(kcontrol))
  		return -EINVAL;
  
  	/* copy URB buffer from EQ template */
  	memcpy(buf, eqs_msq, sizeof(eqs_msq));
  
  	store->val[b_idx][p_idx][index] = val;
  	buf[20] = store->val[b_idx][3][index];
  	buf[17] = store->val[b_idx][2][index];
  	buf[14] = store->val[b_idx][1][index];
  	buf[11] = store->val[b_idx][0][index];
  
  	/* place channel index in URB buffer */
  	buf[5] = index + 1;
  
  	/* place EQ band in URB buffer */
  	buf[8] = b_idx + 1;
  
  	err = snd_us16x08_send_urb(chip, buf, sizeof(eqs_msq));
  
  	if (err > 0) {
  		/* store new value in EQ band cache */
  		elem->cached |= 1 << index;
  		elem->cache_val[index] = val;
  	} else {
  		usb_audio_dbg(chip, "Failed to set eq param, err:%d\n", err);
  	}
  
  	return 1;
  }
  
  static int snd_us16x08_meter_info(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_info *uinfo)
  {
  	uinfo->count = 34;
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
  	uinfo->value.integer.max = 0x7FFF;
  	uinfo->value.integer.min = 0;
  
  	return 0;
  }
  
  /* calculate compressor index for reduction level request */
  static int snd_get_meter_comp_index(struct snd_us16x08_meter_store *store)
  {
  	int ret;
  
  	/* any channel active */
  	if (store->comp_active_index) {
  		/* check for stereo link */
  		if (store->comp_active_index & 0x20) {
  			/* reset comp_index to left channel*/
  			if (store->comp_index -
  				store->comp_active_index > 1)
  				store->comp_index =
  				store->comp_active_index;
  
  			ret = store->comp_index++ & 0x1F;
  		} else {
  			/* no stereo link */
  			ret = store->comp_active_index;
  		}
  	} else {
  		/* skip channels with no compressor active */
  		while (!store->comp_store->val[
  			COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)]
  			[store->comp_index - 1]
  			&& store->comp_index <= SND_US16X08_MAX_CHANNELS) {
  			store->comp_index++;
  		}
  		ret = store->comp_index++;
  		if (store->comp_index > SND_US16X08_MAX_CHANNELS)
  			store->comp_index = 1;
  	}
  	return ret;
  }
  
  /* retrieve the meter level values from URB message */
  static void get_meter_levels_from_urb(int s,
  	struct snd_us16x08_meter_store *store,
  	u8 *meter_urb)
  {
  	int val = MUC2(meter_urb, s) + (MUC3(meter_urb, s) << 8);
  
  	if (MUA0(meter_urb, s) == 0x61 && MUA1(meter_urb, s) == 0x02 &&
  		MUA2(meter_urb, s) == 0x04 && MUB0(meter_urb, s) == 0x62) {
  		if (MUC0(meter_urb, s) == 0x72)
  			store->meter_level[MUB2(meter_urb, s) - 1] = val;
  		if (MUC0(meter_urb, s) == 0xb2)
  			store->comp_level[MUB2(meter_urb, s) - 1] = val;
  	}
  	if (MUA0(meter_urb, s) == 0x61 && MUA1(meter_urb, s) == 0x02 &&
  		MUA2(meter_urb, s) == 0x02 && MUB0(meter_urb, s) == 0x62)
  		store->master_level[MUB2(meter_urb, s) - 1] = val;
  }
  
  /* Function to retrieve current meter values from the device.
   *
   * The device needs to be polled for meter values with an initial
   * requests. It will return with a sequence of different meter value
   * packages. The first request (case 0:) initiate this meter response sequence.
   * After the third response, an additional request can be placed,
   * to retrieve compressor reduction level value for given channel. This round
   * trip channel selector will skip all inactive compressors.
   * A mixer can interrupt this round-trip by selecting one ore two (stereo-link)
   * specific channels.
   */
  static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	int i, set;
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_usb_audio *chip = elem->head.mixer->chip;
  	struct snd_us16x08_meter_store *store = elem->private_data;
  	u8 meter_urb[64];
  
  	switch (kcontrol->private_value) {
  	case 0: {
  		char tmp[sizeof(mix_init_msg1)];
  
  		memcpy(tmp, mix_init_msg1, sizeof(mix_init_msg1));
  		snd_us16x08_send_urb(chip, tmp, 4);
  		snd_us16x08_recv_urb(chip, meter_urb,
  			sizeof(meter_urb));
  		kcontrol->private_value++;
  		break;
  	}
  	case 1:
  		snd_us16x08_recv_urb(chip, meter_urb,
  			sizeof(meter_urb));
  		kcontrol->private_value++;
  		break;
  	case 2:
  		snd_us16x08_recv_urb(chip, meter_urb,
  			sizeof(meter_urb));
  		kcontrol->private_value++;
  		break;
  	case 3: {
  		char tmp[sizeof(mix_init_msg2)];
  
  		memcpy(tmp, mix_init_msg2, sizeof(mix_init_msg2));
  		tmp[2] = snd_get_meter_comp_index(store);
  		snd_us16x08_send_urb(chip, tmp, 10);
  		snd_us16x08_recv_urb(chip, meter_urb,
  			sizeof(meter_urb));
  		kcontrol->private_value = 0;
  		break;
  	}
  	}
  
  	for (set = 0; set < 6; set++)
  		get_meter_levels_from_urb(set, store, meter_urb);
  
  	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
  		ucontrol->value.integer.value[i] =
  			store ? store->meter_level[i] : 0;
  	}
  
  	ucontrol->value.integer.value[i++] = store ? store->master_level[0] : 0;
  	ucontrol->value.integer.value[i++] = store ? store->master_level[1] : 0;
  
  	for (i = 2; i < SND_US16X08_MAX_CHANNELS + 2; i++)
  		ucontrol->value.integer.value[i + SND_US16X08_MAX_CHANNELS] =
  		store ? store->comp_level[i - 2] : 0;
  
  	return 1;
  }
  
  static int snd_us16x08_meter_put(struct snd_kcontrol *kcontrol,
  	struct snd_ctl_elem_value *ucontrol)
  {
  	struct usb_mixer_elem_info *elem = kcontrol->private_data;
  	struct snd_us16x08_meter_store *store = elem->private_data;
  	int val;
  
  	val = ucontrol->value.integer.value[0];
  
  	/* sanity check */
  	if (val < 0 || val >= SND_US16X08_MAX_CHANNELS)
  		return -EINVAL;
  
  	store->comp_active_index = val;
  	store->comp_index = val;
  
  	return 1;
  }
  
  static const struct snd_kcontrol_new snd_us16x08_ch_boolean_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_switch_info,
  	.get = snd_us16x08_channel_get,
  	.put = snd_us16x08_channel_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_ch_int_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_channel_get,
  	.put = snd_us16x08_channel_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 133)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_pan_int_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_channel_get,
  	.put = snd_us16x08_channel_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 255)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_master_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 1,
  	.info = snd_us16x08_master_info,
  	.get = snd_us16x08_master_get,
  	.put = snd_us16x08_master_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 133)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_route_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 8,
  	.info = snd_us16x08_route_info,
  	.get = snd_us16x08_route_get,
  	.put = snd_us16x08_route_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 9)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_bus_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 1,
  	.info = snd_us16x08_switch_info,
  	.get = snd_us16x08_bus_get,
  	.put = snd_us16x08_bus_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_compswitch_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_switch_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_comp_threshold_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_COMP_THRESHOLD_BIAS, 1,
  	0, 0x20)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_comp_ratio_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0,
  	sizeof(ratio_map) - 1), /*max*/
  };
  
  static const struct snd_kcontrol_new snd_us16x08_comp_gain_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x14)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_comp_attack_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value =
  	SND_US16X08_KCSET(SND_US16X08_COMP_ATTACK_BIAS, 1, 0, 0xc6),
  };
  
  static const struct snd_kcontrol_new snd_us16x08_comp_release_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_comp_get,
  	.put = snd_us16x08_comp_put,
  	.private_value =
  	SND_US16X08_KCSET(SND_US16X08_COMP_RELEASE_BIAS, 1, 0, 0x63),
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_gain_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_eq_get,
  	.put = snd_us16x08_eq_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 24),
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_low_freq_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_eq_get,
  	.put = snd_us16x08_eq_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x1F),
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_mid_freq_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_eq_get,
  	.put = snd_us16x08_eq_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x3F)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_mid_width_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_eq_get,
  	.put = snd_us16x08_eq_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x06)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_high_freq_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_mix_info,
  	.get = snd_us16x08_eq_get,
  	.put = snd_us16x08_eq_put,
  	.private_value =
  	SND_US16X08_KCSET(SND_US16X08_EQ_HIGHFREQ_BIAS, 1, 0, 0x1F)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_eq_switch_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 16,
  	.info = snd_us16x08_switch_info,
  	.get = snd_us16x08_eqswitch_get,
  	.put = snd_us16x08_eqswitch_put,
  	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
  };
  
  static const struct snd_kcontrol_new snd_us16x08_meter_ctl = {
  	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
  	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
  	.count = 1,
  	.info = snd_us16x08_meter_info,
  	.get = snd_us16x08_meter_get,
  	.put = snd_us16x08_meter_put
  };
  
  /* control store preparation */
  
  /* setup compressor store and assign default value */
  static struct snd_us16x08_comp_store *snd_us16x08_create_comp_store(void)
  {
  	int i;
  	struct snd_us16x08_comp_store *tmp;
  
  	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
  	if (!tmp)
  		return NULL;
  
  	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD)][i]
  			= 0x20;
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RATIO)][i] = 0x00;
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_GAIN)][i] = 0x00;
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)][i] = 0x00;
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_ATTACK)][i] = 0x00;
  		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RELEASE)][i] = 0x00;
  	}
  	return tmp;
  }
  
  /* setup EQ store and assign default values */
  static struct snd_us16x08_eq_store *snd_us16x08_create_eq_store(void)
  {
  	int i, b_idx;
  	struct snd_us16x08_eq_store *tmp;
  
  	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
  	if (!tmp)
  		return NULL;
  
  	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
  		for (b_idx = 0; b_idx < SND_US16X08_ID_EQ_BAND_COUNT; b_idx++) {
  			tmp->val[b_idx][0][i] = 0x0c;
  			tmp->val[b_idx][3][i] = 0x00;
  			switch (b_idx) {
  			case 0: /* EQ Low */
  				tmp->val[b_idx][1][i] = 0x05;
  				tmp->val[b_idx][2][i] = 0xff;
  				break;
  			case 1: /* EQ Mid low */
  				tmp->val[b_idx][1][i] = 0x0e;
  				tmp->val[b_idx][2][i] = 0x02;
  				break;
  			case 2: /* EQ Mid High */
  				tmp->val[b_idx][1][i] = 0x1b;
  				tmp->val[b_idx][2][i] = 0x02;
  				break;
  			case 3: /* EQ High */
  				tmp->val[b_idx][1][i] = 0x2f
  					- SND_US16X08_EQ_HIGHFREQ_BIAS;
  				tmp->val[b_idx][2][i] = 0xff;
  				break;
  			}
  		}
  	}
  	return tmp;
  }
  
  static struct snd_us16x08_meter_store *snd_us16x08_create_meter_store(void)
  {
  	struct snd_us16x08_meter_store *tmp;
  
  	tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
  	if (!tmp)
  		return NULL;
  	tmp->comp_index = 1;
  	tmp->comp_active_index = 0;
  	return tmp;
  }
  
  /* release elem->private_free as well; called only once for each *_store */
  static void elem_private_free(struct snd_kcontrol *kctl)
  {
  	struct usb_mixer_elem_info *elem = kctl->private_data;
  
  	if (elem)
  		kfree(elem->private_data);
  	kfree(elem);
  	kctl->private_data = NULL;
  }
  
  static int add_new_ctl(struct usb_mixer_interface *mixer,
  	const struct snd_kcontrol_new *ncontrol,
  	int index, int val_type, int channels,
  	const char *name, void *opt,
  	bool do_private_free,
  	struct usb_mixer_elem_info **elem_ret)
  {
  	struct snd_kcontrol *kctl;
  	struct usb_mixer_elem_info *elem;
  	int err;
  
  	usb_audio_dbg(mixer->chip, "us16x08 add mixer %s\n", name);
  
  	elem = kzalloc(sizeof(*elem), GFP_KERNEL);
  	if (!elem)
  		return -ENOMEM;
  
  	elem->head.mixer = mixer;
  	elem->head.resume = NULL;
  	elem->control = 0;
  	elem->idx_off = 0;
  	elem->head.id = index;
  	elem->val_type = val_type;
  	elem->channels = channels;
  	elem->private_data = opt;
  
  	kctl = snd_ctl_new1(ncontrol, elem);
  	if (!kctl) {
  		kfree(elem);
  		return -ENOMEM;
  	}
  
  	if (do_private_free)
  		kctl->private_free = elem_private_free;
  	else
  		kctl->private_free = snd_usb_mixer_elem_free;
  
  	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
  
  	err = snd_usb_mixer_add_control(&elem->head, kctl);
  	if (err < 0)
  		return err;
  
  	if (elem_ret)
  		*elem_ret = elem;
  
  	return 0;
  }
  
  /* table of EQ controls */
  static const struct snd_us16x08_control_params eq_controls[] = {
  	{ /* EQ switch */
  		.kcontrol_new = &snd_us16x08_eq_switch_ctl,
  		.control_id = SND_US16X08_ID_EQENABLE,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "EQ Switch",
  	},
  	{ /* EQ low gain */
  		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
  		.control_id = SND_US16X08_ID_EQLOWLEVEL,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ Low Volume",
  	},
  	{ /* EQ low freq */
  		.kcontrol_new = &snd_us16x08_eq_low_freq_ctl,
  		.control_id = SND_US16X08_ID_EQLOWFREQ,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ Low Frequency",
  	},
  	{ /* EQ mid low gain */
  		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
  		.control_id = SND_US16X08_ID_EQLOWMIDLEVEL,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidLow Volume",
  	},
  	{ /* EQ mid low freq */
  		.kcontrol_new = &snd_us16x08_eq_mid_freq_ctl,
  		.control_id = SND_US16X08_ID_EQLOWMIDFREQ,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidLow Frequency",
  	},
  	{ /* EQ mid low Q */
  		.kcontrol_new = &snd_us16x08_eq_mid_width_ctl,
  		.control_id = SND_US16X08_ID_EQLOWMIDWIDTH,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidLow Q",
  	},
  	{ /* EQ mid high gain */
  		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
  		.control_id = SND_US16X08_ID_EQHIGHMIDLEVEL,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidHigh Volume",
  	},
  	{ /* EQ mid high freq */
  		.kcontrol_new = &snd_us16x08_eq_mid_freq_ctl,
  		.control_id = SND_US16X08_ID_EQHIGHMIDFREQ,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidHigh Frequency",
  	},
  	{ /* EQ mid high Q */
  		.kcontrol_new = &snd_us16x08_eq_mid_width_ctl,
  		.control_id = SND_US16X08_ID_EQHIGHMIDWIDTH,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ MidHigh Q",
  	},
  	{ /* EQ high gain */
  		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
  		.control_id = SND_US16X08_ID_EQHIGHLEVEL,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ High Volume",
  	},
  	{ /* EQ low freq */
  		.kcontrol_new = &snd_us16x08_eq_high_freq_ctl,
  		.control_id = SND_US16X08_ID_EQHIGHFREQ,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "EQ High Frequency",
  	},
  };
  
  /* table of compressor controls */
  static const struct snd_us16x08_control_params comp_controls[] = {
  	{ /* Comp enable */
  		.kcontrol_new = &snd_us16x08_compswitch_ctl,
  		.control_id = SND_US16X08_ID_COMP_SWITCH,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "Compressor Switch",
  	},
  	{ /* Comp threshold */
  		.kcontrol_new = &snd_us16x08_comp_threshold_ctl,
  		.control_id = SND_US16X08_ID_COMP_THRESHOLD,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Compressor Threshold Volume",
  	},
  	{ /* Comp ratio */
  		.kcontrol_new = &snd_us16x08_comp_ratio_ctl,
  		.control_id = SND_US16X08_ID_COMP_RATIO,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Compressor Ratio",
  	},
  	{ /* Comp attack */
  		.kcontrol_new = &snd_us16x08_comp_attack_ctl,
  		.control_id = SND_US16X08_ID_COMP_ATTACK,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Compressor Attack",
  	},
  	{ /* Comp release */
  		.kcontrol_new = &snd_us16x08_comp_release_ctl,
  		.control_id = SND_US16X08_ID_COMP_RELEASE,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Compressor Release",
  	},
  	{ /* Comp gain */
  		.kcontrol_new = &snd_us16x08_comp_gain_ctl,
  		.control_id = SND_US16X08_ID_COMP_GAIN,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Compressor Volume",
  	},
  };
  
  /* table of channel controls */
  static const struct snd_us16x08_control_params channel_controls[] = {
  	{ /* Phase */
  		.kcontrol_new = &snd_us16x08_ch_boolean_ctl,
  		.control_id = SND_US16X08_ID_PHASE,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "Phase Switch",
  		.default_val = 0
  	},
  	{ /* Fader */
  		.kcontrol_new = &snd_us16x08_ch_int_ctl,
  		.control_id = SND_US16X08_ID_FADER,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Line Volume",
  		.default_val = 127
  	},
  	{ /* Mute */
  		.kcontrol_new = &snd_us16x08_ch_boolean_ctl,
  		.control_id = SND_US16X08_ID_MUTE,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "Mute Switch",
  		.default_val = 0
  	},
  	{ /* Pan */
  		.kcontrol_new = &snd_us16x08_pan_int_ctl,
  		.control_id = SND_US16X08_ID_PAN,
  		.type = USB_MIXER_U16,
  		.num_channels = 16,
  		.name = "Pan Left-Right Volume",
  		.default_val = 127
  	},
  };
  
  /* table of master controls */
  static const struct snd_us16x08_control_params master_controls[] = {
  	{ /* Master */
  		.kcontrol_new = &snd_us16x08_master_ctl,
  		.control_id = SND_US16X08_ID_FADER,
  		.type = USB_MIXER_U8,
  		.num_channels = 16,
  		.name = "Master Volume",
  		.default_val = 127
  	},
  	{ /* Bypass */
  		.kcontrol_new = &snd_us16x08_bus_ctl,
  		.control_id = SND_US16X08_ID_BYPASS,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "DSP Bypass Switch",
  		.default_val = 0
  	},
  	{ /* Buss out */
  		.kcontrol_new = &snd_us16x08_bus_ctl,
  		.control_id = SND_US16X08_ID_BUSS_OUT,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "Buss Out Switch",
  		.default_val = 0
  	},
  	{ /* Master mute */
  		.kcontrol_new = &snd_us16x08_bus_ctl,
  		.control_id = SND_US16X08_ID_MUTE,
  		.type = USB_MIXER_BOOLEAN,
  		.num_channels = 16,
  		.name = "Master Mute Switch",
  		.default_val = 0
  	},
  
  };
  
  int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
  {
  	int i, j;
  	int err;
  	struct usb_mixer_elem_info *elem;
  	struct snd_us16x08_comp_store *comp_store;
  	struct snd_us16x08_meter_store *meter_store;
  	struct snd_us16x08_eq_store *eq_store;
  
  	/* just check for non-MIDI interface */
  	if (mixer->hostif->desc.bInterfaceNumber == 3) {
  
  		/* add routing control */
  		err = add_new_ctl(mixer, &snd_us16x08_route_ctl,
  			SND_US16X08_ID_ROUTE, USB_MIXER_U8, 8, "Line Out Route",
  			NULL, false, &elem);
  		if (err < 0) {
  			usb_audio_dbg(mixer->chip,
  				"Failed to create route control, err:%d\n",
  				err);
  			return err;
  		}
  		for (i = 0; i < 8; i++)
  			elem->cache_val[i] = i < 2 ? i : i + 2;
  		elem->cached = 0xff;
  
  		/* create compressor mixer elements */
  		comp_store = snd_us16x08_create_comp_store();
  		if (!comp_store)
  			return -ENOMEM;
  
  		/* add master controls */
  		for (i = 0; i < ARRAY_SIZE(master_controls); i++) {
  
  			err = add_new_ctl(mixer,
  				master_controls[i].kcontrol_new,
  				master_controls[i].control_id,
  				master_controls[i].type,
  				master_controls[i].num_channels,
  				master_controls[i].name,
  				comp_store,
  				i == 0, /* release comp_store only once */
  				&elem);
  			if (err < 0)
  				return err;
  			elem->cache_val[0] = master_controls[i].default_val;
  			elem->cached = 1;
  		}
  
  		/* add channel controls */
  		for (i = 0; i < ARRAY_SIZE(channel_controls); i++) {
  
  			err = add_new_ctl(mixer,
  				channel_controls[i].kcontrol_new,
  				channel_controls[i].control_id,
  				channel_controls[i].type,
  				channel_controls[i].num_channels,
  				channel_controls[i].name,
  				comp_store,
  				false, &elem);
  			if (err < 0)
  				return err;
  			for (j = 0; j < SND_US16X08_MAX_CHANNELS; j++) {
  				elem->cache_val[j] =
  					channel_controls[i].default_val;
  			}
  			elem->cached = 0xffff;
  		}
  
  		/* create eq store */
  		eq_store = snd_us16x08_create_eq_store();
  		if (!eq_store)
  			return -ENOMEM;
  
  		/* add EQ controls */
  		for (i = 0; i < ARRAY_SIZE(eq_controls); i++) {
  
  			err = add_new_ctl(mixer,
  				eq_controls[i].kcontrol_new,
  				eq_controls[i].control_id,
  				eq_controls[i].type,
  				eq_controls[i].num_channels,
  				eq_controls[i].name,
  				eq_store,
  				i == 0, /* release eq_store only once */
  				NULL);
  			if (err < 0)
  				return err;
  		}
  
  		/* add compressor controls */
  		for (i = 0; i < ARRAY_SIZE(comp_controls); i++) {
  
  			err = add_new_ctl(mixer,
  				comp_controls[i].kcontrol_new,
  				comp_controls[i].control_id,
  				comp_controls[i].type,
  				comp_controls[i].num_channels,
  				comp_controls[i].name,
  				comp_store,
  				false, NULL);
  			if (err < 0)
  				return err;
  		}
  
  		/* create meters store */
  		meter_store = snd_us16x08_create_meter_store();
  		if (!meter_store)
  			return -ENOMEM;
  
  		/* meter function 'get' must access to compressor store
  		 * so place a reference here
  		 */
  		meter_store->comp_store = comp_store;
  		err = add_new_ctl(mixer, &snd_us16x08_meter_ctl,
  			SND_US16X08_ID_METER, USB_MIXER_U16, 0, "Level Meter",
  			meter_store, true, NULL);
  		if (err < 0)
  			return err;
  	}
  
  	return 0;
  }
  
  