diff --git a/sound/firewire/Kconfig b/sound/firewire/Kconfig
index 052e005902590c41247bff33f415b430e0c8744d..b9e96d0b3a0a232f20661eaf04bf533351741d56 100644
--- a/sound/firewire/Kconfig
+++ b/sound/firewire/Kconfig
@@ -163,5 +163,6 @@ config SND_FIREFACE
 	 Say Y here to include support for RME fireface series.
 	  * Fireface 400
 	  * Fireface 800
+	  * Fireface UCX
 
 endif # SND_FIREWIRE
diff --git a/sound/firewire/fireface/Makefile b/sound/firewire/fireface/Makefile
index 62eb78962b93ba73a5226e9ed8ab48c9a4ed37ad..d64f4e2a10966eb7310ba40bd436ea5497e2bf44 100644
--- a/sound/firewire/fireface/Makefile
+++ b/sound/firewire/fireface/Makefile
@@ -1,3 +1,4 @@
 snd-fireface-objs := ff.o ff-transaction.o ff-midi.o ff-proc.o amdtp-ff.o \
-		     ff-stream.o ff-pcm.o ff-hwdep.o ff-protocol-former.o
+		     ff-stream.o ff-pcm.o ff-hwdep.o ff-protocol-former.o \
+		     ff-protocol-latter.o
 obj-$(CONFIG_SND_FIREFACE) += snd-fireface.o
diff --git a/sound/firewire/fireface/ff-protocol-latter.c b/sound/firewire/fireface/ff-protocol-latter.c
new file mode 100644
index 0000000000000000000000000000000000000000..64767ba439dbbec7336735ef6b78b9e97b633fd6
--- /dev/null
+++ b/sound/firewire/fireface/ff-protocol-latter.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0
+// ff-protocol-latter - a part of driver for RME Fireface series
+//
+// Copyright (c) 2019 Takashi Sakamoto
+//
+// Licensed under the terms of the GNU General Public License, version 2.
+
+#include <linux/delay.h>
+
+#include "ff.h"
+
+#define LATTER_STF		0xffff00000004
+#define LATTER_ISOC_CHANNELS	0xffff00000008
+#define LATTER_ISOC_START	0xffff0000000c
+#define LATTER_FETCH_MODE	0xffff00000010
+#define LATTER_SYNC_STATUS	0x0000801c0000
+
+static int parse_clock_bits(u32 data, unsigned int *rate,
+			    enum snd_ff_clock_src *src)
+{
+	static const struct {
+		unsigned int rate;
+		u32 flag;
+	} *rate_entry, rate_entries[] = {
+		{ 32000,	0x00000000, },
+		{ 44100,	0x01000000, },
+		{ 48000,	0x02000000, },
+		{ 64000,	0x04000000, },
+		{ 88200,	0x05000000, },
+		{ 96000,	0x06000000, },
+		{ 128000,	0x08000000, },
+		{ 176400,	0x09000000, },
+		{ 192000,	0x0a000000, },
+	};
+	static const struct {
+		enum snd_ff_clock_src src;
+		u32 flag;
+	} *clk_entry, clk_entries[] = {
+		{ SND_FF_CLOCK_SRC_SPDIF,	0x00000200, },
+		{ SND_FF_CLOCK_SRC_ADAT1,	0x00000400, },
+		{ SND_FF_CLOCK_SRC_WORD,	0x00000600, },
+		{ SND_FF_CLOCK_SRC_INTERNAL,	0x00000e00, },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(rate_entries); ++i) {
+		rate_entry = rate_entries + i;
+		if ((data & 0x0f000000) == rate_entry->flag) {
+			*rate = rate_entry->rate;
+			break;
+		}
+	}
+	if (i == ARRAY_SIZE(rate_entries))
+		return -EIO;
+
+	for (i = 0; i < ARRAY_SIZE(clk_entries); ++i) {
+		clk_entry = clk_entries + i;
+		if ((data & 0x000e00) == clk_entry->flag) {
+			*src = clk_entry->src;
+			break;
+		}
+	}
+	if (i == ARRAY_SIZE(clk_entries))
+		return -EIO;
+
+	return 0;
+}
+
+static int latter_get_clock(struct snd_ff *ff, unsigned int *rate,
+			   enum snd_ff_clock_src *src)
+{
+	__le32 reg;
+	u32 data;
+	int err;
+
+	err = snd_fw_transaction(ff->unit, TCODE_READ_QUADLET_REQUEST,
+				 LATTER_SYNC_STATUS, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return err;
+	data = le32_to_cpu(reg);
+
+	return parse_clock_bits(data, rate, src);
+}
+
+static int latter_switch_fetching_mode(struct snd_ff *ff, bool enable)
+{
+	u32 data;
+	__le32 reg;
+
+	if (enable)
+		data = 0x00000000;
+	else
+		data = 0xffffffff;
+	reg = cpu_to_le32(data);
+
+	return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				  LATTER_FETCH_MODE, &reg, sizeof(reg), 0);
+}
+
+static int keep_resources(struct snd_ff *ff, unsigned int rate)
+{
+	enum snd_ff_stream_mode mode;
+	int i;
+	int err;
+
+	// Check whether the given value is supported or not.
+	for (i = 0; i < CIP_SFC_COUNT; i++) {
+		if (amdtp_rate_table[i] == rate)
+			break;
+	}
+	if (i >= CIP_SFC_COUNT)
+		return -EINVAL;
+
+	err = snd_ff_stream_get_multiplier_mode(i, &mode);
+	if (err < 0)
+		return err;
+
+	/* Keep resources for in-stream. */
+	ff->tx_resources.channels_mask = 0x00000000000000ffuLL;
+	err = fw_iso_resources_allocate(&ff->tx_resources,
+			amdtp_stream_get_max_payload(&ff->tx_stream),
+			fw_parent_device(ff->unit)->max_speed);
+	if (err < 0)
+		return err;
+
+	/* Keep resources for out-stream. */
+	ff->rx_resources.channels_mask = 0x00000000000000ffuLL;
+	err = fw_iso_resources_allocate(&ff->rx_resources,
+			amdtp_stream_get_max_payload(&ff->rx_stream),
+			fw_parent_device(ff->unit)->max_speed);
+	if (err < 0)
+		fw_iso_resources_free(&ff->tx_resources);
+
+	return err;
+}
+
+static int latter_begin_session(struct snd_ff *ff, unsigned int rate)
+{
+	static const struct {
+		unsigned int stf;
+		unsigned int code;
+		unsigned int flag;
+	} *entry, rate_table[] = {
+		{ 32000,  0x00, 0x92, },
+		{ 44100,  0x02, 0x92, },
+		{ 48000,  0x04, 0x92, },
+		{ 64000,  0x08, 0x8e, },
+		{ 88200,  0x0a, 0x8e, },
+		{ 96000,  0x0c, 0x8e, },
+		{ 128000, 0x10, 0x8c, },
+		{ 176400, 0x12, 0x8c, },
+		{ 192000, 0x14, 0x8c, },
+	};
+	u32 data;
+	__le32 reg;
+	unsigned int count;
+	int i;
+	int err;
+
+	for (i = 0; i < ARRAY_SIZE(rate_table); ++i) {
+		entry = rate_table + i;
+		if (entry->stf == rate)
+			break;
+	}
+	if (i == ARRAY_SIZE(rate_table))
+		return -EINVAL;
+
+	reg = cpu_to_le32(entry->code);
+	err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 LATTER_STF, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return err;
+
+	// Confirm to shift transmission clock.
+	count = 0;
+	while (count++ < 10) {
+		unsigned int curr_rate;
+		enum snd_ff_clock_src src;
+
+		err = latter_get_clock(ff, &curr_rate, &src);
+		if (err < 0)
+			return err;
+
+		if (curr_rate == rate)
+			break;
+	}
+	if (count == 10)
+		return -ETIMEDOUT;
+
+	err = keep_resources(ff, rate);
+	if (err < 0)
+		return err;
+
+	data = (ff->tx_resources.channel << 8) | ff->rx_resources.channel;
+	reg = cpu_to_le32(data);
+	err = snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 LATTER_ISOC_CHANNELS, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return err;
+
+	// Always use the maximum number of data channels in data block of
+	// packet.
+	reg = cpu_to_le32(entry->flag);
+	return snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+				  LATTER_ISOC_START, &reg, sizeof(reg), 0);
+}
+
+static void latter_finish_session(struct snd_ff *ff)
+{
+	__le32 reg;
+
+	reg = cpu_to_le32(0x00000000);
+	snd_fw_transaction(ff->unit, TCODE_WRITE_QUADLET_REQUEST,
+			   LATTER_ISOC_START, &reg, sizeof(reg), 0);
+}
+
+static void latter_dump_status(struct snd_ff *ff, struct snd_info_buffer *buffer)
+{
+	static const struct {
+		char *const label;
+		u32 locked_mask;
+		u32 synced_mask;
+	} *clk_entry, clk_entries[] = {
+		{ "S/PDIF",	0x00000001, 0x00000010, },
+		{ "ADAT",	0x00000002, 0x00000020, },
+		{ "WDClk",	0x00000004, 0x00000040, },
+	};
+	__le32 reg;
+	u32 data;
+	unsigned int rate;
+	enum snd_ff_clock_src src;
+	const char *label;
+	int i;
+	int err;
+
+	err = snd_fw_transaction(ff->unit, TCODE_READ_QUADLET_REQUEST,
+				 LATTER_SYNC_STATUS, &reg, sizeof(reg), 0);
+	if (err < 0)
+		return;
+	data = le32_to_cpu(reg);
+
+	snd_iprintf(buffer, "External source detection:\n");
+
+	for (i = 0; i < ARRAY_SIZE(clk_entries); ++i) {
+		clk_entry = clk_entries + i;
+		snd_iprintf(buffer, "%s: ", clk_entry->label);
+		if (data & clk_entry->locked_mask) {
+			if (data & clk_entry->synced_mask)
+				snd_iprintf(buffer, "sync\n");
+			else
+				snd_iprintf(buffer, "lock\n");
+		} else {
+			snd_iprintf(buffer, "none\n");
+		}
+	}
+
+	err = parse_clock_bits(data, &rate, &src);
+	if (err < 0)
+		return;
+	label = snd_ff_proc_get_clk_label(src);
+	if (!label)
+		return;
+
+	snd_iprintf(buffer, "Referred clock: %s %d\n", label, rate);
+}
+
+const struct snd_ff_protocol snd_ff_protocol_latter = {
+	.get_clock		= latter_get_clock,
+	.switch_fetching_mode	= latter_switch_fetching_mode,
+	.begin_session		= latter_begin_session,
+	.finish_session		= latter_finish_session,
+	.dump_status		= latter_dump_status,
+};
diff --git a/sound/firewire/fireface/ff.c b/sound/firewire/fireface/ff.c
index 36575f4159d13cc0be238ba25704521fb718e711..fd9c980e3cf4b92735905e9a3ee274dc6cceb4bc 100644
--- a/sound/firewire/fireface/ff.c
+++ b/sound/firewire/fireface/ff.c
@@ -32,7 +32,8 @@ static void ff_card_free(struct snd_card *card)
 	struct snd_ff *ff = card->private_data;
 
 	snd_ff_stream_destroy_duplex(ff);
-	snd_ff_transaction_unregister(ff);
+	if (ff->spec->midi_high_addr > 0)
+		snd_ff_transaction_unregister(ff);
 }
 
 static void do_registration(struct work_struct *work)
@@ -50,9 +51,11 @@ static void do_registration(struct work_struct *work)
 	ff->card->private_free = ff_card_free;
 	ff->card->private_data = ff;
 
-	err = snd_ff_transaction_register(ff);
-	if (err < 0)
-		goto error;
+	if (ff->spec->midi_high_addr > 0) {
+		err = snd_ff_transaction_register(ff);
+		if (err < 0)
+			goto error;
+	}
 
 	name_card(ff);
 
@@ -62,9 +65,11 @@ static void do_registration(struct work_struct *work)
 
 	snd_ff_proc_init(ff);
 
-	err = snd_ff_create_midi_devices(ff);
-	if (err < 0)
-		goto error;
+	if (ff->spec->midi_in_ports > 0 || ff->spec->midi_out_ports > 0) {
+		err = snd_ff_create_midi_devices(ff);
+		if (err < 0)
+			goto error;
+	}
 
 	err = snd_ff_create_pcm_devices(ff);
 	if (err < 0)
@@ -119,7 +124,8 @@ static void snd_ff_update(struct fw_unit *unit)
 	if (!ff->registered)
 		snd_fw_schedule_registration(unit, &ff->dwork);
 
-	snd_ff_transaction_reregister(ff);
+	if (ff->spec->midi_high_addr > 0)
+		snd_ff_transaction_reregister(ff);
 
 	if (ff->registered)
 		snd_ff_stream_update_duplex(ff);
@@ -165,6 +171,13 @@ static const struct snd_ff_spec spec_ff400 = {
 	.midi_high_addr = 0x0000801003f4ull,
 };
 
+static const struct snd_ff_spec spec_ucx = {
+	.name = "FirefaceUCX",
+	.pcm_capture_channels = {18, 14, 12},
+	.pcm_playback_channels = {18, 14, 12},
+	.protocol = &snd_ff_protocol_latter,
+};
+
 static const struct ieee1394_device_id snd_ff_id_table[] = {
 	/* Fireface 800 */
 	{
@@ -190,6 +203,18 @@ static const struct ieee1394_device_id snd_ff_id_table[] = {
 		.model_id	= 0x101800,
 		.driver_data	= (kernel_ulong_t)&spec_ff400,
 	},
+	// Fireface UCX.
+	{
+		.match_flags	= IEEE1394_MATCH_VENDOR_ID |
+				  IEEE1394_MATCH_SPECIFIER_ID |
+				  IEEE1394_MATCH_VERSION |
+				  IEEE1394_MATCH_MODEL_ID,
+		.vendor_id	= OUI_RME,
+		.specifier_id	= OUI_RME,
+		.version	= 0x000004,
+		.model_id	= 0x101800,
+		.driver_data	= (kernel_ulong_t)&spec_ucx,
+	},
 	{}
 };
 MODULE_DEVICE_TABLE(ieee1394, snd_ff_id_table);
diff --git a/sound/firewire/fireface/ff.h b/sound/firewire/fireface/ff.h
index cdb16e931c3126f3d2bbe127f7d5c0eb7acce11d..8aea7920b57f3d38eebfa352b836c47e38bde7a7 100644
--- a/sound/firewire/fireface/ff.h
+++ b/sound/firewire/fireface/ff.h
@@ -114,6 +114,7 @@ struct snd_ff_protocol {
 
 extern const struct snd_ff_protocol snd_ff_protocol_ff800;
 extern const struct snd_ff_protocol snd_ff_protocol_ff400;
+extern const struct snd_ff_protocol snd_ff_protocol_latter;
 
 int snd_ff_transaction_register(struct snd_ff *ff);
 int snd_ff_transaction_reregister(struct snd_ff *ff);