sound/firewire/motu/motu-protocol-v2.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * motu-protocol-v2.c - a part of driver for MOTU FireWire series
  *
  * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
  */

 #include "motu.h"

 #define V2_CLOCK_STATUS_OFFSET			0x0b14
 #define  V2_CLOCK_RATE_MASK			0x00000038
 #define  V2_CLOCK_RATE_SHIFT			3
 #define  V2_CLOCK_SRC_MASK			0x00000007
 #define  V2_CLOCK_SRC_SHIFT			0
 #define  V2_CLOCK_FETCH_ENABLE			0x02000000
 #define  V2_CLOCK_MODEL_SPECIFIC		0x04000000

 #define V2_IN_OUT_CONF_OFFSET			0x0c04
 #define  V2_OPT_OUT_IFACE_MASK			0x00000c00
 #define  V2_OPT_OUT_IFACE_SHIFT			10
 #define  V2_OPT_IN_IFACE_MASK			0x00000300
 #define  V2_OPT_IN_IFACE_SHIFT			8
 #define  V2_OPT_IFACE_MODE_NONE			0
 #define  V2_OPT_IFACE_MODE_ADAT			1
 #define  V2_OPT_IFACE_MODE_SPDIF		2

 static int get_clock_rate(u32 data, unsigned int *rate)
 {
 	unsigned int index = (data & V2_CLOCK_RATE_MASK) >> V2_CLOCK_RATE_SHIFT;
 	if (index >= ARRAY_SIZE(snd_motu_clock_rates))
 		return -EIO;

 	*rate = snd_motu_clock_rates[index];

 	return 0;
 }

 int snd_motu_protocol_v2_get_clock_rate(struct snd_motu *motu,
 					unsigned int *rate)
 {
 	__be32 reg;
 	int err;

 	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
 					sizeof(reg));
 	if (err < 0)
 		return err;

 	return get_clock_rate(be32_to_cpu(reg), rate);
 }

 int snd_motu_protocol_v2_set_clock_rate(struct snd_motu *motu,
 					unsigned int rate)
 {
 	__be32 reg;
 	u32 data;
 	int i;
 	int err;

 	for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
 		if (snd_motu_clock_rates[i] == rate)
 			break;
 	}
 	if (i == ARRAY_SIZE(snd_motu_clock_rates))
 		return -EINVAL;

 	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
 					sizeof(reg));
 	if (err < 0)
 		return err;
 	data = be32_to_cpu(reg);

 	data &= ~V2_CLOCK_RATE_MASK;
 	data |= i << V2_CLOCK_RATE_SHIFT;

 	reg = cpu_to_be32(data);
 	return snd_motu_transaction_write(motu, V2_CLOCK_STATUS_OFFSET, &reg,
 					  sizeof(reg));
 }

 static int detect_clock_source_optical_model(struct snd_motu *motu, u32 data,
 					     enum snd_motu_clock_source *src)
 {
 	switch (data) {
 	case 0:
 		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
 		break;
 	case 1:
 		*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT;
 		break;
 	case 2:
 	{
 		__be32 reg;

 		// To check the configuration of optical interface.
 		int err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET, &reg, sizeof(reg));
 		if (err < 0)
 			return err;

 		if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) == V2_OPT_IFACE_MODE_SPDIF)
 			*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT;
 		else
 			*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
 		break;
 	}
 	case 3:
 		*src = SND_MOTU_CLOCK_SOURCE_SPH;
 		break;
 	case 4:
 		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
 		break;
 	case 5:
 		*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_DSUB;
 		break;
 	default:
 		*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
 		break;
 	}

 	return 0;
 }

 static int v2_detect_clock_source(struct snd_motu *motu, u32 data,
 				  enum snd_motu_clock_source *src)
 {
 	switch (data) {
 	case 0:
 		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
 		break;
 	case 2:
 		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
 		break;
 	case 3:
 		*src = SND_MOTU_CLOCK_SOURCE_SPH;
 		break;
 	case 4:
 		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
 		break;
 	default:
 		*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
 		break;
 	}

 	return 0;
 }

 static int get_clock_source(struct snd_motu *motu, u32 data,
 			    enum snd_motu_clock_source *src)
 {
 	data &= V2_CLOCK_SRC_MASK;
 	if (motu->spec == &snd_motu_spec_828mk2 ||
 	    motu->spec == &snd_motu_spec_traveler)
 		return detect_clock_source_optical_model(motu, data, src);
 	else
 		return v2_detect_clock_source(motu, data, src);
 }

 int snd_motu_protocol_v2_get_clock_source(struct snd_motu *motu,
 					  enum snd_motu_clock_source *src)
 {
 	__be32 reg;
 	int err;

 	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
 					sizeof(reg));
 	if (err < 0)
 		return err;

 	return get_clock_source(motu, be32_to_cpu(reg), src);
 }

 // Expected for Traveler and 896HD, which implements Altera Cyclone EP1C3.
 static int switch_fetching_mode_cyclone(struct snd_motu *motu, u32 *data,
 					bool enable)
 {
 	*data |= V2_CLOCK_MODEL_SPECIFIC;

 	return 0;
 }

 // For UltraLite and 8pre, which implements Xilinx Spartan XC3S200.
 static int switch_fetching_mode_spartan(struct snd_motu *motu, u32 *data,
 					bool enable)
 {
 	unsigned int rate;
 	enum snd_motu_clock_source src;
 	int err;

 	err = get_clock_source(motu, *data, &src);
 	if (err < 0)
 		return err;

 	err = get_clock_rate(*data, &rate);
 	if (err < 0)
 		return err;

 	if (src == SND_MOTU_CLOCK_SOURCE_SPH && rate > 48000)
 		*data |= V2_CLOCK_MODEL_SPECIFIC;

 	return 0;
 }

 int snd_motu_protocol_v2_switch_fetching_mode(struct snd_motu *motu,
 					      bool enable)
 {
 	if (motu->spec == &snd_motu_spec_828mk2) {
 		// 828mkII implements Altera ACEX 1K EP1K30. Nothing to do.
 		return 0;
 	} else {
 		__be32 reg;
 		u32 data;
 		int err;

 		err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET,
 						&reg, sizeof(reg));
 		if (err < 0)
 			return err;
 		data = be32_to_cpu(reg);

 		data &= ~(V2_CLOCK_FETCH_ENABLE | V2_CLOCK_MODEL_SPECIFIC);
 		if (enable)
 			data |= V2_CLOCK_FETCH_ENABLE;

 		if (motu->spec == &snd_motu_spec_traveler)
 			err = switch_fetching_mode_cyclone(motu, &data, enable);
 		else
 			err = switch_fetching_mode_spartan(motu, &data, enable);
 		if (err < 0)
 			return err;

 		reg = cpu_to_be32(data);
 		return snd_motu_transaction_write(motu, V2_CLOCK_STATUS_OFFSET,
 						  &reg, sizeof(reg));
 	}
 }

 static int detect_packet_formats_828mk2(struct snd_motu *motu, u32 data)
 {
 	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->tx_packet_formats.pcm_chunks[0] += 8;
 		motu->tx_packet_formats.pcm_chunks[1] += 4;
 	}

 	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->rx_packet_formats.pcm_chunks[0] += 8;
 		motu->rx_packet_formats.pcm_chunks[1] += 4;
 	}

 	return 0;
 }

 static int detect_packet_formats_traveler(struct snd_motu *motu, u32 data)
 {
 	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->tx_packet_formats.pcm_chunks[0] += 8;
 		motu->tx_packet_formats.pcm_chunks[1] += 4;
 	}

 	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->rx_packet_formats.pcm_chunks[0] += 8;
 		motu->rx_packet_formats.pcm_chunks[1] += 4;
 	}

 	return 0;
 }

 static int detect_packet_formats_8pre(struct snd_motu *motu, u32 data)
 {
 	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->tx_packet_formats.pcm_chunks[0] += 8;
 		motu->tx_packet_formats.pcm_chunks[1] += 8;
 	}

 	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
 	    V2_OPT_IFACE_MODE_ADAT) {
 		motu->rx_packet_formats.pcm_chunks[0] += 8;
 		motu->rx_packet_formats.pcm_chunks[1] += 8;
 	}

 	return 0;
 }

 int snd_motu_protocol_v2_cache_packet_formats(struct snd_motu *motu)
 {
 	__be32 reg;
 	u32 data;
 	int err;

 	motu->tx_packet_formats.pcm_byte_offset = 10;
 	motu->rx_packet_formats.pcm_byte_offset = 10;

 	motu->tx_packet_formats.msg_chunks = 2;
 	motu->rx_packet_formats.msg_chunks = 2;

 	err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET, &reg,
 					sizeof(reg));
 	if (err < 0)
 		return err;
 	data = be32_to_cpu(reg);

 	memcpy(motu->tx_packet_formats.pcm_chunks,
 	       motu->spec->tx_fixed_pcm_chunks,
 	       sizeof(motu->tx_packet_formats.pcm_chunks));
 	memcpy(motu->rx_packet_formats.pcm_chunks,
 	       motu->spec->rx_fixed_pcm_chunks,
 	       sizeof(motu->rx_packet_formats.pcm_chunks));

 	if (motu->spec == &snd_motu_spec_828mk2)
 		return detect_packet_formats_828mk2(motu, data);
 	else if (motu->spec == &snd_motu_spec_traveler)
 		return detect_packet_formats_traveler(motu, data);
 	else if (motu->spec == &snd_motu_spec_8pre)
 		return detect_packet_formats_8pre(motu, data);
 	else
 		return 0;
 }

 const struct snd_motu_spec snd_motu_spec_828mk2 = {
 	.name = "828mk2",
 	.protocol_version = SND_MOTU_PROTOCOL_V2,
 	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q |
 		 SND_MOTU_SPEC_TX_MIDI_2ND_Q,
 	.tx_fixed_pcm_chunks = {14, 14, 0},
 	.rx_fixed_pcm_chunks = {14, 14, 0},
 };

 const struct snd_motu_spec snd_motu_spec_traveler = {
 	.name = "Traveler",
 	.protocol_version = SND_MOTU_PROTOCOL_V2,
 	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q |
 		 SND_MOTU_SPEC_TX_MIDI_2ND_Q,
 	.tx_fixed_pcm_chunks = {14, 14, 8},
 	.rx_fixed_pcm_chunks = {14, 14, 8},
 };

 const struct snd_motu_spec snd_motu_spec_ultralite = {
 	.name = "UltraLite",
 	.protocol_version = SND_MOTU_PROTOCOL_V2,
 	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q |
 		 SND_MOTU_SPEC_TX_MIDI_2ND_Q,
 	.tx_fixed_pcm_chunks = {14, 14, 0},
 	.rx_fixed_pcm_chunks = {14, 14, 0},
 };

 const struct snd_motu_spec snd_motu_spec_8pre = {
 	.name = "8pre",
 	.protocol_version = SND_MOTU_PROTOCOL_V2,
 	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q |
 		 SND_MOTU_SPEC_TX_MIDI_2ND_Q,
 	// Two dummy chunks always in the end of data block.
 	.tx_fixed_pcm_chunks = {10, 10, 0},
 	.rx_fixed_pcm_chunks = {6, 6, 0},
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* motu-protocol-v2.c - a part of driver for MOTU FireWire series
	*
	* Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
	*/

	#include "motu.h"

	#define V2_CLOCK_STATUS_OFFSET 0x0b14
	#define V2_CLOCK_RATE_MASK 0x00000038
	#define V2_CLOCK_RATE_SHIFT 3
	#define V2_CLOCK_SRC_MASK 0x00000007
	#define V2_CLOCK_SRC_SHIFT 0
	#define V2_CLOCK_FETCH_ENABLE 0x02000000
	#define V2_CLOCK_MODEL_SPECIFIC 0x04000000

	#define V2_IN_OUT_CONF_OFFSET 0x0c04
	#define V2_OPT_OUT_IFACE_MASK 0x00000c00
	#define V2_OPT_OUT_IFACE_SHIFT 10
	#define V2_OPT_IN_IFACE_MASK 0x00000300
	#define V2_OPT_IN_IFACE_SHIFT 8
	#define V2_OPT_IFACE_MODE_NONE 0
	#define V2_OPT_IFACE_MODE_ADAT 1
	#define V2_OPT_IFACE_MODE_SPDIF 2

	static int get_clock_rate(u32 data, unsigned int *rate)
	{
	unsigned int index = (data & V2_CLOCK_RATE_MASK) >> V2_CLOCK_RATE_SHIFT;
	if (index >= ARRAY_SIZE(snd_motu_clock_rates))
	return -EIO;

	*rate = snd_motu_clock_rates[index];

	return 0;
	}

	int snd_motu_protocol_v2_get_clock_rate(struct snd_motu *motu,
	unsigned int *rate)
	{
	__be32 reg;
	int err;

	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
	sizeof(reg));
	if (err < 0)
	return err;

	return get_clock_rate(be32_to_cpu(reg), rate);
	}

	int snd_motu_protocol_v2_set_clock_rate(struct snd_motu *motu,
	unsigned int rate)
	{
	__be32 reg;
	u32 data;
	int i;
	int err;

	for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
	if (snd_motu_clock_rates[i] == rate)
	break;
	}
	if (i == ARRAY_SIZE(snd_motu_clock_rates))
	return -EINVAL;

	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
	sizeof(reg));
	if (err < 0)
	return err;
	data = be32_to_cpu(reg);

	data &= ~V2_CLOCK_RATE_MASK;
	data \|= i << V2_CLOCK_RATE_SHIFT;

	reg = cpu_to_be32(data);
	return snd_motu_transaction_write(motu, V2_CLOCK_STATUS_OFFSET, &reg,
	sizeof(reg));
	}

	static int detect_clock_source_optical_model(struct snd_motu *motu, u32 data,
	enum snd_motu_clock_source *src)
	{
	switch (data) {
	case 0:
	*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
	break;
	case 1:
	*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT;
	break;
	case 2:
	{
	__be32 reg;

	// To check the configuration of optical interface.
	int err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET, &reg, sizeof(reg));
	if (err < 0)
	return err;

	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) == V2_OPT_IFACE_MODE_SPDIF)
	*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT;
	else
	*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
	break;
	}
	case 3:
	*src = SND_MOTU_CLOCK_SOURCE_SPH;
	break;
	case 4:
	*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
	break;
	case 5:
	*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_DSUB;
	break;
	default:
	*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
	break;
	}

	return 0;
	}

	static int v2_detect_clock_source(struct snd_motu *motu, u32 data,
	enum snd_motu_clock_source *src)
	{
	switch (data) {
	case 0:
	*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
	break;
	case 2:
	*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
	break;
	case 3:
	*src = SND_MOTU_CLOCK_SOURCE_SPH;
	break;
	case 4:
	*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
	break;
	default:
	*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
	break;
	}

	return 0;
	}

	static int get_clock_source(struct snd_motu *motu, u32 data,
	enum snd_motu_clock_source *src)
	{
	data &= V2_CLOCK_SRC_MASK;
	if (motu->spec == &snd_motu_spec_828mk2 \|\|
	motu->spec == &snd_motu_spec_traveler)
	return detect_clock_source_optical_model(motu, data, src);
	else
	return v2_detect_clock_source(motu, data, src);
	}

	int snd_motu_protocol_v2_get_clock_source(struct snd_motu *motu,
	enum snd_motu_clock_source *src)
	{
	__be32 reg;
	int err;

	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET, &reg,
	sizeof(reg));
	if (err < 0)
	return err;

	return get_clock_source(motu, be32_to_cpu(reg), src);
	}

	// Expected for Traveler and 896HD, which implements Altera Cyclone EP1C3.
	static int switch_fetching_mode_cyclone(struct snd_motu motu, u32 data,
	bool enable)
	{
	*data \|= V2_CLOCK_MODEL_SPECIFIC;

	return 0;
	}

	// For UltraLite and 8pre, which implements Xilinx Spartan XC3S200.
	static int switch_fetching_mode_spartan(struct snd_motu motu, u32 data,
	bool enable)
	{
	unsigned int rate;
	enum snd_motu_clock_source src;
	int err;

	err = get_clock_source(motu, *data, &src);
	if (err < 0)
	return err;

	err = get_clock_rate(*data, &rate);
	if (err < 0)
	return err;

	if (src == SND_MOTU_CLOCK_SOURCE_SPH && rate > 48000)
	*data \|= V2_CLOCK_MODEL_SPECIFIC;

	return 0;
	}

	int snd_motu_protocol_v2_switch_fetching_mode(struct snd_motu *motu,
	bool enable)
	{
	if (motu->spec == &snd_motu_spec_828mk2) {
	// 828mkII implements Altera ACEX 1K EP1K30. Nothing to do.
	return 0;
	} else {
	__be32 reg;
	u32 data;
	int err;

	err = snd_motu_transaction_read(motu, V2_CLOCK_STATUS_OFFSET,
	&reg, sizeof(reg));
	if (err < 0)
	return err;
	data = be32_to_cpu(reg);

	data &= ~(V2_CLOCK_FETCH_ENABLE \| V2_CLOCK_MODEL_SPECIFIC);
	if (enable)
	data \|= V2_CLOCK_FETCH_ENABLE;

	if (motu->spec == &snd_motu_spec_traveler)
	err = switch_fetching_mode_cyclone(motu, &data, enable);
	else
	err = switch_fetching_mode_spartan(motu, &data, enable);
	if (err < 0)
	return err;

	reg = cpu_to_be32(data);
	return snd_motu_transaction_write(motu, V2_CLOCK_STATUS_OFFSET,
	&reg, sizeof(reg));
	}
	}

	static int detect_packet_formats_828mk2(struct snd_motu *motu, u32 data)
	{
	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->tx_packet_formats.pcm_chunks[0] += 8;
	motu->tx_packet_formats.pcm_chunks[1] += 4;
	}

	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->rx_packet_formats.pcm_chunks[0] += 8;
	motu->rx_packet_formats.pcm_chunks[1] += 4;
	}

	return 0;
	}

	static int detect_packet_formats_traveler(struct snd_motu *motu, u32 data)
	{
	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->tx_packet_formats.pcm_chunks[0] += 8;
	motu->tx_packet_formats.pcm_chunks[1] += 4;
	}

	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->rx_packet_formats.pcm_chunks[0] += 8;
	motu->rx_packet_formats.pcm_chunks[1] += 4;
	}

	return 0;
	}

	static int detect_packet_formats_8pre(struct snd_motu *motu, u32 data)
	{
	if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->tx_packet_formats.pcm_chunks[0] += 8;
	motu->tx_packet_formats.pcm_chunks[1] += 8;
	}

	if (((data & V2_OPT_OUT_IFACE_MASK) >> V2_OPT_OUT_IFACE_SHIFT) ==
	V2_OPT_IFACE_MODE_ADAT) {
	motu->rx_packet_formats.pcm_chunks[0] += 8;
	motu->rx_packet_formats.pcm_chunks[1] += 8;
	}

	return 0;
	}

	int snd_motu_protocol_v2_cache_packet_formats(struct snd_motu *motu)
	{
	__be32 reg;
	u32 data;
	int err;

	motu->tx_packet_formats.pcm_byte_offset = 10;
	motu->rx_packet_formats.pcm_byte_offset = 10;

	motu->tx_packet_formats.msg_chunks = 2;
	motu->rx_packet_formats.msg_chunks = 2;

	err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET, &reg,
	sizeof(reg));
	if (err < 0)
	return err;
	data = be32_to_cpu(reg);

	memcpy(motu->tx_packet_formats.pcm_chunks,
	motu->spec->tx_fixed_pcm_chunks,
	sizeof(motu->tx_packet_formats.pcm_chunks));
	memcpy(motu->rx_packet_formats.pcm_chunks,
	motu->spec->rx_fixed_pcm_chunks,
	sizeof(motu->rx_packet_formats.pcm_chunks));

	if (motu->spec == &snd_motu_spec_828mk2)
	return detect_packet_formats_828mk2(motu, data);
	else if (motu->spec == &snd_motu_spec_traveler)
	return detect_packet_formats_traveler(motu, data);
	else if (motu->spec == &snd_motu_spec_8pre)
	return detect_packet_formats_8pre(motu, data);
	else
	return 0;
	}

	const struct snd_motu_spec snd_motu_spec_828mk2 = {
	.name = "828mk2",
	.protocol_version = SND_MOTU_PROTOCOL_V2,
	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q \|
	SND_MOTU_SPEC_TX_MIDI_2ND_Q,
	.tx_fixed_pcm_chunks = {14, 14, 0},
	.rx_fixed_pcm_chunks = {14, 14, 0},
	};

	const struct snd_motu_spec snd_motu_spec_traveler = {
	.name = "Traveler",
	.protocol_version = SND_MOTU_PROTOCOL_V2,
	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q \|
	SND_MOTU_SPEC_TX_MIDI_2ND_Q,
	.tx_fixed_pcm_chunks = {14, 14, 8},
	.rx_fixed_pcm_chunks = {14, 14, 8},
	};

	const struct snd_motu_spec snd_motu_spec_ultralite = {
	.name = "UltraLite",
	.protocol_version = SND_MOTU_PROTOCOL_V2,
	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q \|
	SND_MOTU_SPEC_TX_MIDI_2ND_Q,
	.tx_fixed_pcm_chunks = {14, 14, 0},
	.rx_fixed_pcm_chunks = {14, 14, 0},
	};

	const struct snd_motu_spec snd_motu_spec_8pre = {
	.name = "8pre",
	.protocol_version = SND_MOTU_PROTOCOL_V2,
	.flags = SND_MOTU_SPEC_RX_MIDI_2ND_Q \|
	SND_MOTU_SPEC_TX_MIDI_2ND_Q,
	// Two dummy chunks always in the end of data block.
	.tx_fixed_pcm_chunks = {10, 10, 0},
	.rx_fixed_pcm_chunks = {6, 6, 0},
	};