ALSA: usb: initial USB Audio Device Class 3.0 support

Recently released USB Audio Class 3.0 specification
introduces many significant changes comparing to
previous versions, like
- new Power Domains, support for LPM/L1
- new Cluster descriptor
- changed layout of all class-specific descriptors
- new High Capability descriptors
- New class-specific String descriptors
- new and removed units
- additional sources for interrupts
- removed Type II Audio Data Formats
- ... and many other things (check spec)

It also provides backward compatibility through
multiple configurations, as well as requires
mandatory support for BADD (Basic Audio Device
Definition) on each ADC3.0 compliant device

This patch adds initial support of UAC3 specification
that is enough for Generic I/O Profile (BAOF, BAIF)
device support from BADD document.

Signed-off-by: Ruslan Bilovol <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

include/linux/usb/audio-v2.h

···
  *
  */
 
-static inline bool uac2_control_is_readable(u32 bmControls, u8 control)
+static inline bool uac_v2v3_control_is_readable(u32 bmControls, u8 control)
 {
 	return (bmControls >> (control * 2)) & 0x1;
 }
 
-static inline bool uac2_control_is_writeable(u32 bmControls, u8 control)
+static inline bool uac_v2v3_control_is_writeable(u32 bmControls, u8 control)
 {
 	return (bmControls >> (control * 2)) & 0x2;
 }

include/linux/usb/audio-v3.h

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2017 Ruslan Bilovol <[e-mail]>
+ *
+ * This file holds USB constants and structures defined
+ * by the USB DEVICE CLASS DEFINITION FOR AUDIO DEVICES Release 3.0.
+ */
+
+#ifndef __LINUX_USB_AUDIO_V3_H
+#define __LINUX_USB_AUDIO_V3_H
+
+#include <linux/types.h>
+
+/*
+ * v1.0, v2.0 and v3.0 of this standard have many things in common. For the rest
+ * of the definitions, please refer to audio.h and audio-v2.h
+ */
+
+/* All High Capability descriptors have these 2 fields at the beginning */
+struct uac3_hc_descriptor_header {
+	__le16 wLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__le16 wDescriptorID;
+} __attribute__ ((packed));
+
+/* 4.3.1 CLUSTER DESCRIPTOR HEADER */
+struct uac3_cluster_header_descriptor {
+	__le16 wLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__le16 wDescriptorID;
+	__u8 bNrChannels;
+} __attribute__ ((packed));
+
+/* 4.3.2.1 SEGMENTS */
+struct uac3_cluster_segment_descriptor {
+	__le16 wLength;
+	__u8 bSegmentType;
+	/* __u8[0]; segment-specific data */
+} __attribute__ ((packed));
+
+/* 4.3.2.1.1 END SEGMENT */
+struct uac3_cluster_end_segment_descriptor {
+	__le16 wLength;
+	__u8 bSegmentType;		/* Constant END_SEGMENT */
+} __attribute__ ((packed));
+
+/* 4.3.2.1.3.1 INFORMATION SEGMENT */
+struct uac3_cluster_information_segment_descriptor {
+	__le16 wLength;
+	__u8 bSegmentType;
+	__u8 bChPurpose;
+	__u8 bChRelationship;
+	__u8 bChGroupID;
+} __attribute__ ((packed));
+
+/* 4.5.2 CLASS-SPECIFIC AC INTERFACE DESCRIPTOR */
+struct uac3_ac_header_descriptor {
+	__u8 bLength;			/* 10 */
+	__u8 bDescriptorType;		/* CS_INTERFACE descriptor type */
+	__u8 bDescriptorSubtype;	/* HEADER descriptor subtype */
+	__u8 bCategory;
+
+	/* includes Clock Source, Unit, Terminal, and Power Domain desc. */
+	__le16 wTotalLength;
+
+	__le32 bmControls;
+} __attribute__ ((packed));
+
+/* 4.5.2.1 INPUT TERMINAL DESCRIPTOR */
+struct uac3_input_terminal_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bTerminalID;
+	__le16 wTerminalType;
+	__u8 bAssocTerminal;
+	__u8 bCSourceID;
+	__le32 bmControls;
+	__le16 wClusterDescrID;
+	__le16 wExTerminalDescrID;
+	__le16 wConnectorsDescrID;
+	__le16 wTerminalDescrStr;
+} __attribute__((packed));
+
+/* 4.5.2.2 OUTPUT TERMINAL DESCRIPTOR */
+struct uac3_output_terminal_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bTerminalID;
+	__le16 wTerminalType;
+	__u8 bAssocTerminal;
+	__u8 bSourceID;
+	__u8 bCSourceID;
+	__le32 bmControls;
+	__le16 wExTerminalDescrID;
+	__le16 wConnectorsDescrID;
+	__le16 wTerminalDescrStr;
+} __attribute__((packed));
+
+/* 4.5.2.7 FEATURE UNIT DESCRIPTOR */
+struct uac3_feature_unit_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bUnitID;
+	__u8 bSourceID;
+	/* bmaControls is actually u32,
+	 * but u8 is needed for the hybrid parser */
+	__u8 bmaControls[0]; /* variable length */
+	/* wFeatureDescrStr omitted */
+} __attribute__((packed));
+
+#define UAC3_DT_FEATURE_UNIT_SIZE(ch)		(7 + ((ch) + 1) * 4)
+
+/* As above, but more useful for defining your own descriptors */
+#define DECLARE_UAC3_FEATURE_UNIT_DESCRIPTOR(ch)		\
+struct uac3_feature_unit_descriptor_##ch {			\
+	__u8 bLength;						\
+	__u8 bDescriptorType;					\
+	__u8 bDescriptorSubtype;				\
+	__u8 bUnitID;						\
+	__u8 bSourceID;						\
+	__le32 bmaControls[ch + 1];				\
+	__le16 wFeatureDescrStr;				\
+} __attribute__ ((packed))
+
+/* 4.5.2.12 CLOCK SOURCE DESCRIPTOR */
+struct uac3_clock_source_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bClockID;
+	__u8 bmAttributes;
+	__le32 bmControls;
+	__u8 bReferenceTerminal;
+	__le16 wClockSourceStr;
+} __attribute__((packed));
+
+/* bmAttribute fields */
+#define UAC3_CLOCK_SOURCE_TYPE_EXT	0x0
+#define UAC3_CLOCK_SOURCE_TYPE_INT	0x1
+#define UAC3_CLOCK_SOURCE_ASYNC		(0 << 2)
+#define UAC3_CLOCK_SOURCE_SYNCED_TO_SOF	(1 << 1)
+
+/* 4.5.2.13 CLOCK SELECTOR DESCRIPTOR */
+struct uac3_clock_selector_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bClockID;
+	__u8 bNrInPins;
+	__u8 baCSourceID[];
+	/* bmControls and wCSelectorDescrStr omitted */
+} __attribute__((packed));
+
+/* 4.5.2.14 CLOCK MULTIPLIER DESCRIPTOR */
+struct uac3_clock_multiplier_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bClockID;
+	__u8 bCSourceID;
+	__le32 bmControls;
+	__le16 wCMultiplierDescrStr;
+} __attribute__((packed));
+
+/* 4.5.2.15 POWER DOMAIN DESCRIPTOR */
+struct uac3_power_domain_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bPowerDomainID;
+	__le16 waRecoveryTime1;
+	__le16 waRecoveryTime2;
+	__u8 bNrEntities;
+	__u8 baEntityID[];
+	/* wPDomainDescrStr omitted */
+} __attribute__((packed));
+
+/* As above, but more useful for defining your own descriptors */
+#define DECLARE_UAC3_POWER_DOMAIN_DESCRIPTOR(n)			\
+struct uac3_power_domain_descriptor_##n {			\
+	__u8 bLength;						\
+	__u8 bDescriptorType;					\
+	__u8 bDescriptorSubtype;				\
+	__u8 bPowerDomainID;					\
+	__le16 waRecoveryTime1;					\
+	__le16 waRecoveryTime2;					\
+	__u8 bNrEntities;					\
+	__u8 baEntityID[n];					\
+	__le16 wPDomainDescrStr;					\
+} __attribute__ ((packed))
+
+/* 4.7.2 CLASS-SPECIFIC AS INTERFACE DESCRIPTOR */
+struct uac3_as_header_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__u8 bTerminalLink;
+	__le32 bmControls;
+	__le16 wClusterDescrID;
+	__le64 bmFormats;
+	__u8 bSubslotSize;
+	__u8 bBitResolution;
+	__le16 bmAuxProtocols;
+	__u8 bControlSize;
+} __attribute__((packed));
+
+#define UAC3_FORMAT_TYPE_I_RAW_DATA	(1 << 6)
+
+/* 4.8.1.2 CLASS-SPECIFIC AS ISOCHRONOUS AUDIO DATA ENDPOINT DESCRIPTOR */
+struct uac3_iso_endpoint_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDescriptorSubtype;
+	__le32 bmControls;
+	__u8 bLockDelayUnits;
+	__le16 wLockDelay;
+} __attribute__((packed));
+
+/* 6.1 INTERRUPT DATA MESSAGE */
+struct uac3_interrupt_data_msg {
+	__u8 bInfo;
+	__u8 bSourceType;
+	__le16 wValue;
+	__le16 wIndex;
+} __attribute__((packed));
+
+/* A.2 AUDIO AUDIO FUNCTION SUBCLASS CODES */
+#define UAC3_FUNCTION_SUBCLASS_UNDEFINED	0x00
+#define UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0	0x01
+/* BADD profiles */
+#define UAC3_FUNCTION_SUBCLASS_GENERIC_IO	0x20
+#define UAC3_FUNCTION_SUBCLASS_HEADPHONE	0x21
+#define UAC3_FUNCTION_SUBCLASS_SPEAKER		0x22
+#define UAC3_FUNCTION_SUBCLASS_MICROPHONE	0x23
+#define UAC3_FUNCTION_SUBCLASS_HEADSET		0x24
+#define UAC3_FUNCTION_SUBCLASS_HEADSET_ADAPTER	0x25
+#define UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE	0x26
+
+/* A.7 AUDIO FUNCTION CATEGORY CODES */
+#define UAC3_FUNCTION_SUBCLASS_UNDEFINED	0x00
+#define UAC3_FUNCTION_DESKTOP_SPEAKER		0x01
+#define UAC3_FUNCTION_HOME_THEATER		0x02
+#define UAC3_FUNCTION_MICROPHONE		0x03
+#define UAC3_FUNCTION_HEADSET			0x04
+#define UAC3_FUNCTION_TELEPHONE			0x05
+#define UAC3_FUNCTION_CONVERTER			0x06
+#define UAC3_FUNCTION_SOUND_RECORDER		0x07
+#define UAC3_FUNCTION_IO_BOX			0x08
+#define UAC3_FUNCTION_MUSICAL_INSTRUMENT	0x09
+#define UAC3_FUNCTION_PRO_AUDIO			0x0a
+#define UAC3_FUNCTION_AUDIO_VIDEO		0x0b
+#define UAC3_FUNCTION_CONTROL_PANEL		0x0c
+#define UAC3_FUNCTION_HEADPHONE			0x0d
+#define UAC3_FUNCTION_GENERIC_SPEAKER		0x0e
+#define UAC3_FUNCTION_HEADSET_ADAPTER		0x0f
+#define UAC3_FUNCTION_SPEAKERPHONE		0x10
+#define UAC3_FUNCTION_OTHER			0xff
+
+/* A.8 AUDIO CLASS-SPECIFIC DESCRIPTOR TYPES */
+#define UAC3_CS_UNDEFINED		0x20
+#define UAC3_CS_DEVICE			0x21
+#define UAC3_CS_CONFIGURATION		0x22
+#define UAC3_CS_STRING			0x23
+#define UAC3_CS_INTERFACE		0x24
+#define UAC3_CS_ENDPOINT		0x25
+#define UAC3_CS_CLUSTER			0x26
+
+/* A.10 CLUSTER DESCRIPTOR SEGMENT TYPES */
+#define UAC3_SEGMENT_UNDEFINED		0x00
+#define UAC3_CLUSTER_DESCRIPTION	0x01
+#define UAC3_CLUSTER_VENDOR_DEFINED	0x1F
+#define UAC3_CHANNEL_INFORMATION	0x20
+#define UAC3_CHANNEL_AMBISONIC		0x21
+#define UAC3_CHANNEL_DESCRIPTION	0x22
+#define UAC3_CHANNEL_VENDOR_DEFINED	0xFE
+#define UAC3_END_SEGMENT		0xFF
+
+/* A.11 CHANNEL PURPOSE DEFINITIONS */
+#define UAC3_PURPOSE_UNDEFINED		0x00
+#define UAC3_PURPOSE_GENERIC_AUDIO	0x01
+#define UAC3_PURPOSE_VOICE		0x02
+#define UAC3_PURPOSE_SPEECH		0x03
+#define UAC3_PURPOSE_AMBIENT		0x04
+#define UAC3_PURPOSE_REFERENCE		0x05
+#define UAC3_PURPOSE_ULTRASONIC		0x06
+#define UAC3_PURPOSE_VIBROKINETIC	0x07
+#define UAC3_PURPOSE_NON_AUDIO		0xFF
+
+/* A.12 CHANNEL RELATIONSHIP DEFINITIONS */
+#define UAC3_CH_RELATIONSHIP_UNDEFINED	0x00
+#define UAC3_CH_MONO			0x01
+#define UAC3_CH_LEFT			0x02
+#define UAC3_CH_RIGHT			0x03
+#define UAC3_CH_ARRAY			0x04
+#define UAC3_CH_PATTERN_X		0x20
+#define UAC3_CH_PATTERN_Y		0x21
+#define UAC3_CH_PATTERN_A		0x22
+#define UAC3_CH_PATTERN_B		0x23
+#define UAC3_CH_PATTERN_M		0x24
+#define UAC3_CH_PATTERN_S		0x25
+#define UAC3_CH_FRONT_LEFT		0x80
+#define UAC3_CH_FRONT_RIGHT		0x81
+#define UAC3_CH_FRONT_CENTER		0x82
+#define UAC3_CH_FRONT_LEFT_OF_CENTER	0x83
+#define UAC3_CH_FRONT_RIGHT_OF_CENTER	0x84
+#define UAC3_CH_FRONT_WIDE_LEFT		0x85
+#define UAC3_CH_FRONT_WIDE_RIGHT	0x86
+#define UAC3_CH_SIDE_LEFT		0x87
+#define UAC3_CH_SIDE_RIGHT		0x88
+#define UAC3_CH_SURROUND_ARRAY_LEFT	0x89
+#define UAC3_CH_SURROUND_ARRAY_RIGHT	0x8A
+#define UAC3_CH_BACK_LEFT		0x8B
+#define UAC3_CH_BACK_RIGHT		0x8C
+#define UAC3_CH_BACK_CENTER		0x8D
+#define UAC3_CH_BACK_LEFT_OF_CENTER	0x8E
+#define UAC3_CH_BACK_RIGHT_OF_CENTER	0x8F
+#define UAC3_CH_BACK_WIDE_LEFT		0x90
+#define UAC3_CH_BACK_WIDE_RIGHT		0x91
+#define UAC3_CH_TOP_CENTER		0x92
+#define UAC3_CH_TOP_FRONT_LEFT		0x93
+#define UAC3_CH_TOP_FRONT_RIGHT		0x94
+#define UAC3_CH_TOP_FRONT_CENTER	0x95
+#define UAC3_CH_TOP_FRONT_LOC		0x96
+#define UAC3_CH_TOP_FRONT_ROC		0x97
+#define UAC3_CH_TOP_FRONT_WIDE_LEFT	0x98
+#define UAC3_CH_TOP_FRONT_WIDE_RIGHT	0x99
+#define UAC3_CH_TOP_SIDE_LEFT		0x9A
+#define UAC3_CH_TOP_SIDE_RIGHT		0x9B
+#define UAC3_CH_TOP_SURR_ARRAY_LEFT	0x9C
+#define UAC3_CH_TOP_SURR_ARRAY_RIGHT	0x9D
+#define UAC3_CH_TOP_BACK_LEFT		0x9E
+#define UAC3_CH_TOP_BACK_RIGHT		0x9F
+#define UAC3_CH_TOP_BACK_CENTER		0xA0
+#define UAC3_CH_TOP_BACK_LOC		0xA1
+#define UAC3_CH_TOP_BACK_ROC		0xA2
+#define UAC3_CH_TOP_BACK_WIDE_LEFT	0xA3
+#define UAC3_CH_TOP_BACK_WIDE_RIGHT	0xA4
+#define UAC3_CH_BOTTOM_CENTER		0xA5
+#define UAC3_CH_BOTTOM_FRONT_LEFT	0xA6
+#define UAC3_CH_BOTTOM_FRONT_RIGHT	0xA7
+#define UAC3_CH_BOTTOM_FRONT_CENTER	0xA8
+#define UAC3_CH_BOTTOM_FRONT_LOC	0xA9
+#define UAC3_CH_BOTTOM_FRONT_ROC	0xAA
+#define UAC3_CH_BOTTOM_FRONT_WIDE_LEFT	0xAB
+#define UAC3_CH_BOTTOM_FRONT_WIDE_RIGHT	0xAC
+#define UAC3_CH_BOTTOM_SIDE_LEFT	0xAD
+#define UAC3_CH_BOTTOM_SIDE_RIGHT	0xAE
+#define UAC3_CH_BOTTOM_SURR_ARRAY_LEFT	0xAF
+#define UAC3_CH_BOTTOM_SURR_ARRAY_RIGHT	0xB0
+#define UAC3_CH_BOTTOM_BACK_LEFT	0xB1
+#define UAC3_CH_BOTTOM_BACK_RIGHT	0xB2
+#define UAC3_CH_BOTTOM_BACK_CENTER	0xB3
+#define UAC3_CH_BOTTOM_BACK_LOC		0xB4
+#define UAC3_CH_BOTTOM_BACK_ROC		0xB5
+#define UAC3_CH_BOTTOM_BACK_WIDE_LEFT	0xB6
+#define UAC3_CH_BOTTOM_BACK_WIDE_RIGHT	0xB7
+#define UAC3_CH_LOW_FREQUENCY_EFFECTS	0xB8
+#define UAC3_CH_LFE_LEFT		0xB9
+#define UAC3_CH_LFE_RIGHT		0xBA
+#define UAC3_CH_HEADPHONE_LEFT		0xBB
+#define UAC3_CH_HEADPHONE_RIGHT		0xBC
+
+/* A.15 AUDIO CLASS-SPECIFIC AC INTERFACE DESCRIPTOR SUBTYPES */
+/* see audio.h for the rest, which is identical to v1 */
+#define UAC3_EXTENDED_TERMINAL		0x04
+#define UAC3_MIXER_UNIT			0x05
+#define UAC3_SELECTOR_UNIT		0x06
+#define UAC3_FEATURE_UNIT		0x07
+#define UAC3_EFFECT_UNIT		0x08
+#define UAC3_PROCESSING_UNIT		0x09
+#define UAC3_EXTENSION_UNIT		0x0a
+#define UAC3_CLOCK_SOURCE		0x0b
+#define UAC3_CLOCK_SELECTOR		0x0c
+#define UAC3_CLOCK_MULTIPLIER		0x0d
+#define UAC3_SAMPLE_RATE_CONVERTER	0x0e
+#define UAC3_CONNECTORS			0x0f
+#define UAC3_POWER_DOMAIN		0x10
+
+/* A.22 AUDIO CLASS-SPECIFIC REQUEST CODES */
+/* see audio-v2.h for the rest, which is identical to v2 */
+#define UAC3_CS_REQ_INTEN			0x04
+#define UAC3_CS_REQ_STRING			0x05
+#define UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR	0x06
+
+/* A.23.1 AUDIOCONTROL INTERFACE CONTROL SELECTORS */
+#define UAC3_AC_CONTROL_UNDEFINED		0x00
+#define UAC3_AC_ACTIVE_INTERFACE_CONTROL	0x01
+#define UAC3_AC_POWER_DOMAIN_CONTROL		0x02
+
+#endif /* __LINUX_USB_AUDIO_V3_H */

include/uapi/linux/usb/audio.h

···
 /* bInterfaceProtocol values to denote the version of the standard used */
 #define UAC_VERSION_1			0x00
 #define UAC_VERSION_2			0x20
+#define UAC_VERSION_3			0x30
 
 /* A.2 Audio Interface Subclass Codes */
 #define USB_SUBCLASS_AUDIOCONTROL	0x01

sound/usb/card.c

···
  *	    Alan Cox ([e-mail])
  *	    Thomas Sailer ([e-mail])
  *
+ *   Audio Class 3.0 support by Ruslan Bilovol <[e-mail]>
  *
  *   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
···
 #include <linux/mutex.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
 #include <linux/module.h>
 
 #include <sound/control.h>
···
 		break;
 	}
 
-	case UAC_VERSION_2: {
+	case UAC_VERSION_2:
+	case UAC_VERSION_3: {
 		struct usb_interface_assoc_descriptor *assoc =
 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
 
···
 		}
 
 		if (!assoc) {
-			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
+			dev_err(&dev->dev, "Audio class v2/v3 interfaces need an interface association\n");
 			return -EINVAL;
 		}
 

sound/usb/card.h

···
 	unsigned char endpoint;		/* endpoint */
 	unsigned char ep_attr;		/* endpoint attributes */
 	unsigned char datainterval;	/* log_2 of data packet interval */
-	unsigned char protocol;		/* UAC_VERSION_1/2 */
+	unsigned char protocol;		/* UAC_VERSION_1/2/3 */
 	unsigned int maxpacksize;	/* max. packet size */
 	unsigned int rates;		/* rate bitmasks */
 	unsigned int rate_min, rate_max;	/* min/max rates */

sound/usb/clock.c

···
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
 
 #include <sound/core.h>
 #include <sound/info.h>
···
 	return NULL;
 }
 
+static struct uac3_clock_source_descriptor *
+	snd_usb_find_clock_source_v3(struct usb_host_interface *ctrl_iface,
+				  int clock_id)
+{
+	struct uac3_clock_source_descriptor *cs = NULL;
+
+	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
+					     ctrl_iface->extralen,
+					     cs, UAC3_CLOCK_SOURCE))) {
+		if (cs->bClockID == clock_id)
+			return cs;
+	}
+
+	return NULL;
+}
+
 static struct uac_clock_selector_descriptor *
 	snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
 				    int clock_id)
···
 	return NULL;
 }
 
+static struct uac3_clock_selector_descriptor *
+	snd_usb_find_clock_selector_v3(struct usb_host_interface *ctrl_iface,
+				    int clock_id)
+{
+	struct uac3_clock_selector_descriptor *cs = NULL;
+
+	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
+					     ctrl_iface->extralen,
+					     cs, UAC3_CLOCK_SELECTOR))) {
+		if (cs->bClockID == clock_id)
+			return cs;
+	}
+
+	return NULL;
+}
+
 static struct uac_clock_multiplier_descriptor *
 	snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
 				      int clock_id)
···
 					     ctrl_iface->extralen,
 					     cs, UAC2_CLOCK_MULTIPLIER))) {
 		if (cs->bLength >= sizeof(*cs) && cs->bClockID == clock_id)
+			return cs;
+	}
+
+	return NULL;
+}
+
+static struct uac3_clock_multiplier_descriptor *
+	snd_usb_find_clock_multiplier_v3(struct usb_host_interface *ctrl_iface,
+				      int clock_id)
+{
+	struct uac3_clock_multiplier_descriptor *cs = NULL;
+
+	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
+					     ctrl_iface->extralen,
+					     cs, UAC3_CLOCK_MULTIPLIER))) {
+		if (cs->bClockID == clock_id)
 			return cs;
 	}
 
···
 	return ret;
 }
 
-static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
+static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
+				      int protocol,
+				      int source_id)
 {
 	int err;
 	unsigned char data;
 	struct usb_device *dev = chip->dev;
-	struct uac_clock_source_descriptor *cs_desc =
-		snd_usb_find_clock_source(chip->ctrl_intf, source_id);
+	u32 bmControls;
 
-	if (!cs_desc)
-		return 0;
+	if (protocol == UAC_VERSION_3) {
+		struct uac3_clock_source_descriptor *cs_desc =
+			snd_usb_find_clock_source_v3(chip->ctrl_intf, source_id);
+
+		if (!cs_desc)
+			return 0;
+		bmControls = le32_to_cpu(cs_desc->bmControls);
+	} else { /* UAC_VERSION_1/2 */
+		struct uac_clock_source_descriptor *cs_desc =
+			snd_usb_find_clock_source(chip->ctrl_intf, source_id);
+
+		if (!cs_desc)
+			return 0;
+		bmControls = cs_desc->bmControls;
+	}
 
 	/* If a clock source can't tell us whether it's valid, we assume it is */
-	if (!uac2_control_is_readable(cs_desc->bmControls,
+	if (!uac_v2v3_control_is_readable(bmControls,
 				      UAC2_CS_CONTROL_CLOCK_VALID - 1))
 		return 1;
 
···
 	return !!data;
 }
 
-static int __uac_clock_find_source(struct snd_usb_audio *chip,
-				   int entity_id, unsigned long *visited,
-				   bool validate)
+static int __uac_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+				   unsigned long *visited, bool validate)
 {
 	struct uac_clock_source_descriptor *source;
 	struct uac_clock_selector_descriptor *selector;
···
 	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
 	if (source) {
 		entity_id = source->bClockID;
-		if (validate && !uac_clock_source_is_valid(chip, entity_id)) {
+		if (validate && !uac_clock_source_is_valid(chip, UAC_VERSION_2,
+								entity_id)) {
 			usb_audio_err(chip,
 				"clock source %d is not valid, cannot use\n",
 				entity_id);
···
 	return -EINVAL;
 }
 
+static int __uac3_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+				   unsigned long *visited, bool validate)
+{
+	struct uac3_clock_source_descriptor *source;
+	struct uac3_clock_selector_descriptor *selector;
+	struct uac3_clock_multiplier_descriptor *multiplier;
+
+	entity_id &= 0xff;
+
+	if (test_and_set_bit(entity_id, visited)) {
+		usb_audio_warn(chip,
+			 "%s(): recursive clock topology detected, id %d.\n",
+			 __func__, entity_id);
+		return -EINVAL;
+	}
+
+	/* first, see if the ID we're looking for is a clock source already */
+	source = snd_usb_find_clock_source_v3(chip->ctrl_intf, entity_id);
+	if (source) {
+		entity_id = source->bClockID;
+		if (validate && !uac_clock_source_is_valid(chip, UAC_VERSION_3,
+								entity_id)) {
+			usb_audio_err(chip,
+				"clock source %d is not valid, cannot use\n",
+				entity_id);
+			return -ENXIO;
+		}
+		return entity_id;
+	}
+
+	selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf, entity_id);
+	if (selector) {
+		int ret, i, cur;
+
+		/* the entity ID we are looking for is a selector.
+		 * find out what it currently selects */
+		ret = uac_clock_selector_get_val(chip, selector->bClockID);
+		if (ret < 0)
+			return ret;
+
+		/* Selector values are one-based */
+
+		if (ret > selector->bNrInPins || ret < 1) {
+			usb_audio_err(chip,
+				"%s(): selector reported illegal value, id %d, ret %d\n",
+				__func__, selector->bClockID, ret);
+
+			return -EINVAL;
+		}
+
+		cur = ret;
+		ret = __uac3_clock_find_source(chip, selector->baCSourceID[ret - 1],
+					       visited, validate);
+		if (!validate || ret > 0 || !chip->autoclock)
+			return ret;
+
+		/* The current clock source is invalid, try others. */
+		for (i = 1; i <= selector->bNrInPins; i++) {
+			int err;
+
+			if (i == cur)
+				continue;
+
+			ret = __uac3_clock_find_source(chip, selector->baCSourceID[i - 1],
+				visited, true);
+			if (ret < 0)
+				continue;
+
+			err = uac_clock_selector_set_val(chip, entity_id, i);
+			if (err < 0)
+				continue;
+
+			usb_audio_info(chip,
+				 "found and selected valid clock source %d\n",
+				 ret);
+			return ret;
+		}
+
+		return -ENXIO;
+	}
+
+	/* FIXME: multipliers only act as pass-thru element for now */
+	multiplier = snd_usb_find_clock_multiplier_v3(chip->ctrl_intf,
+						      entity_id);
+	if (multiplier)
+		return __uac3_clock_find_source(chip, multiplier->bCSourceID,
+						visited, validate);
+
+	return -EINVAL;
+}
+
 /*
  * For all kinds of sample rate settings and other device queries,
  * the clock source (end-leaf) must be used. However, clock selectors,
···
  *
  * Returns the clock source UnitID (>=0) on success, or an error.
  */
-int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
-			      bool validate)
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int protocol,
+			      int entity_id, bool validate)
 {
 	DECLARE_BITMAP(visited, 256);
 	memset(visited, 0, sizeof(visited));
-	return __uac_clock_find_source(chip, entity_id, visited, validate);
+
+	switch (protocol) {
+	case UAC_VERSION_2:
+		return __uac_clock_find_source(chip, entity_id, visited,
+					       validate);
+	case UAC_VERSION_3:
+		return __uac3_clock_find_source(chip, entity_id, visited,
+					       validate);
+	default:
+		return -EINVAL;
+	}
 }
 
 static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
···
 	return 0;
 }
 
-static int get_sample_rate_v2(struct snd_usb_audio *chip, int iface,
+static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
 			      int altsetting, int clock)
 {
 	struct usb_device *dev = chip->dev;
···
 			      snd_usb_ctrl_intf(chip) | (clock << 8),
 			      &data, sizeof(data));
 	if (err < 0) {
-		dev_warn(&dev->dev, "%d:%d: cannot get freq (v2): err %d\n",
+		dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
 			 iface, altsetting, err);
 		return 0;
 	}
···
 	return le32_to_cpu(data);
 }
 
-static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
+static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
 			      struct usb_host_interface *alts,
 			      struct audioformat *fmt, int rate)
 {
···
 	int err, cur_rate, prev_rate;
 	int clock;
 	bool writeable;
-	struct uac_clock_source_descriptor *cs_desc;
+	u32 bmControls;
 
-	clock = snd_usb_clock_find_source(chip, fmt->clock, true);
+	clock = snd_usb_clock_find_source(chip, fmt->protocol,
+					  fmt->clock, true);
 	if (clock < 0)
 		return clock;
 
-	prev_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
+	prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock);
 	if (prev_rate == rate)
 		return 0;
 
-	cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
-	writeable = uac2_control_is_writeable(cs_desc->bmControls, UAC2_CS_CONTROL_SAM_FREQ - 1);
+	if (fmt->protocol == UAC_VERSION_3) {
+		struct uac3_clock_source_descriptor *cs_desc;
+
+		cs_desc = snd_usb_find_clock_source_v3(chip->ctrl_intf, clock);
+		bmControls = le32_to_cpu(cs_desc->bmControls);
+	} else {
+		struct uac_clock_source_descriptor *cs_desc;
+
+		cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
+		bmControls = cs_desc->bmControls;
+	}
+
+	writeable = uac_v2v3_control_is_writeable(bmControls, UAC2_CS_CONTROL_SAM_FREQ - 1);
 	if (writeable) {
 		data = cpu_to_le32(rate);
 		err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
···
 				      &data, sizeof(data));
 		if (err < 0) {
 			usb_audio_err(chip,
-				"%d:%d: cannot set freq %d (v2): err %d\n",
+				"%d:%d: cannot set freq %d (v2/v3): err %d\n",
 				iface, fmt->altsetting, rate, err);
 			return err;
 		}
 
-		cur_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
+		cur_rate = get_sample_rate_v2v3(chip, iface,
+						fmt->altsetting, clock);
 	} else {
 		cur_rate = prev_rate;
 	}
···
 		return set_sample_rate_v1(chip, iface, alts, fmt, rate);
 
 	case UAC_VERSION_2:
-		return set_sample_rate_v2(chip, iface, alts, fmt, rate);
+	case UAC_VERSION_3:
+		return set_sample_rate_v2v3(chip, iface, alts, fmt, rate);
 	}
 }
 

sound/usb/clock.h

···
 			     struct usb_host_interface *alts,
 			     struct audioformat *fmt, int rate);
 
-int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
-			     bool validate);
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int protocol,
+			     int entity_id, bool validate);
 
 #endif /* __USBAUDIO_CLOCK_H */

sound/usb/format.c

···
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
 
 #include <sound/core.h>
 #include <sound/pcm.h>
···
  * @dev: usb device
  * @fp: audioformat record
  * @format: the format tag (wFormatTag)
- * @fmt: the format type descriptor
+ * @fmt: the format type descriptor (v1/v2) or AudioStreaming descriptor (v3)
  */
 static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
 				     struct audioformat *fp,
-				     unsigned int format, void *_fmt)
+				     u64 format, void *_fmt)
 {
 	int sample_width, sample_bytes;
 	u64 pcm_formats = 0;
···
 		sample_bytes = fmt->bSubslotSize;
 
 		if (format & UAC2_FORMAT_TYPE_I_RAW_DATA)
+			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
+
+		format <<= 1;
+		break;
+	}
+	case UAC_VERSION_3: {
+		struct uac3_as_header_descriptor *as = _fmt;
+
+		sample_width = as->bBitResolution;
+		sample_bytes = as->bSubslotSize;
+
+		if (format & UAC3_FORMAT_TYPE_I_RAW_DATA)
 			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
 
 		format <<= 1;
···
 	}
 	if (format & ~0x3f) {
 		usb_audio_info(chip,
-			 "%u:%d : unsupported format bits %#x\n",
+			 "%u:%d : unsupported format bits %#llx\n",
 			 fp->iface, fp->altsetting, format);
 	}
 
···
 
 /*
  * parse the format descriptor and stores the possible sample rates
- * on the audioformat table (audio class v2).
+ * on the audioformat table (audio class v2 and v3).
  */
-static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
+static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
 				       struct audioformat *fp)
 {
 	struct usb_device *dev = chip->dev;
 	unsigned char tmp[2], *data;
 	int nr_triplets, data_size, ret = 0;
-	int clock = snd_usb_clock_find_source(chip, fp->clock, false);
+	int clock = snd_usb_clock_find_source(chip, fp->protocol,
+					      fp->clock, false);
 
 	if (clock < 0) {
 		dev_err(&dev->dev,
···
  * parse the format type I and III descriptors
  */
 static int parse_audio_format_i(struct snd_usb_audio *chip,
-				struct audioformat *fp, unsigned int format,
-				struct uac_format_type_i_continuous_descriptor *fmt)
+				struct audioformat *fp, u64 format,
+				void *_fmt)
 {
 	snd_pcm_format_t pcm_format;
+	unsigned int fmt_type;
 	int ret;
 
-	if (fmt->bFormatType == UAC_FORMAT_TYPE_III) {
+	switch (fp->protocol) {
+	default:
+	case UAC_VERSION_1:
+	case UAC_VERSION_2: {
+		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
+
+		fmt_type = fmt->bFormatType;
+		break;
+	}
+	case UAC_VERSION_3: {
+		/* fp->fmt_type is already set in this case */
+		fmt_type = fp->fmt_type;
+		break;
+	}
+	}
+
+	if (fmt_type == UAC_FORMAT_TYPE_III) {
 		/* FIXME: the format type is really IECxxx
 		 *        but we give normal PCM format to get the existing
 		 *        apps working...
···
 		}
 		fp->formats = pcm_format_to_bits(pcm_format);
 	} else {
-		fp->formats = parse_audio_format_i_type(chip, fp, format, fmt);
+		fp->formats = parse_audio_format_i_type(chip, fp, format, _fmt);
 		if (!fp->formats)
 			return -EINVAL;
 	}
···
 	 */
 	switch (fp->protocol) {
 	default:
-	case UAC_VERSION_1:
+	case UAC_VERSION_1: {
+		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
+
 		fp->channels = fmt->bNrChannels;
 		ret = parse_audio_format_rates_v1(chip, fp, (unsigned char *) fmt, 7);
 		break;
+	}
 	case UAC_VERSION_2:
+	case UAC_VERSION_3: {
 		/* fp->channels is already set in this case */
-		ret = parse_audio_format_rates_v2(chip, fp);
+		ret = parse_audio_format_rates_v2v3(chip, fp);
 		break;
+	}
 	}
 
 	if (fp->channels < 1) {
···
  */
 static int parse_audio_format_ii(struct snd_usb_audio *chip,
 				 struct audioformat *fp,
-				 int format, void *_fmt)
+				 u64 format, void *_fmt)
 {
 	int brate, framesize, ret;
 
···
 		break;
 	default:
 		usb_audio_info(chip,
-			 "%u:%d : unknown format tag %#x is detected.  processed as MPEG.\n",
+			 "%u:%d : unknown format tag %#llx is detected.  processed as MPEG.\n",
 			 fp->iface, fp->altsetting, format);
 		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
 		break;
···
 		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
 		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
 		fp->frame_size = framesize;
-		ret = parse_audio_format_rates_v2(chip, fp);
+		ret = parse_audio_format_rates_v2v3(chip, fp);
 		break;
 	}
 	}
···
 }
 
 int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
-			       struct audioformat *fp, unsigned int format,
+			       struct audioformat *fp, u64 format,
 			       struct uac_format_type_i_continuous_descriptor *fmt,
 			       int stream)
 {
···
 	return 0;
 }
 
+int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
+			       struct audioformat *fp,
+			       struct uac3_as_header_descriptor *as,
+			       int stream)
+{
+	u64 format = le64_to_cpu(as->bmFormats);
+	int err;
+
+	/*
+	 * Type I format bits are D0..D6
+	 * This test works because type IV is not supported
+	 */
+	if (format & 0x7f)
+		fp->fmt_type = UAC_FORMAT_TYPE_I;
+	else
+		fp->fmt_type = UAC_FORMAT_TYPE_III;
+
+	err = parse_audio_format_i(chip, fp, format, as);
+	if (err < 0)
+		return err;
+
+	return 0;
+}

sound/usb/format.h

···
 #define __USBAUDIO_FORMAT_H
 
 int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
-			       struct audioformat *fp, unsigned int format,
+			       struct audioformat *fp, u64 format,
 			       struct uac_format_type_i_continuous_descriptor *fmt,
 			       int stream);
 
+int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
+			       struct audioformat *fp,
+			       struct uac3_as_header_descriptor *as,
+			       int stream);
 #endif /*  __USBAUDIO_FORMAT_H */

sound/usb/mixer.c

···
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
 
 #include <sound/core.h>
 #include <sound/control.h>
···
 					USB_DT_CS_INTERFACE)) != NULL) {
 		if (hdr->bLength >= 4 &&
 		    hdr->bDescriptorSubtype >= UAC_INPUT_TERMINAL &&
-		    hdr->bDescriptorSubtype <= UAC2_SAMPLE_RATE_CONVERTER &&
+		    hdr->bDescriptorSubtype <= UAC3_SAMPLE_RATE_CONVERTER &&
 		    hdr->bUnitID == unit)
 			return hdr;
 	}
···
 
 	validx += cval->idx_off;
 
+
 	if (cval->head.mixer->protocol == UAC_VERSION_1) {
 		val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
-	} else { /* UAC_VERSION_2 */
+	} else { /* UAC_VERSION_2/3 */
 		val_len = uac2_ctl_value_size(cval->val_type);
 
 		/* FIXME */
···
 static int check_input_term(struct mixer_build *state, int id,
 			    struct usb_audio_term *term)
 {
+	int protocol = state->mixer->protocol;
 	int err;
 	void *p1;
 
···
 	while ((p1 = find_audio_control_unit(state, id)) != NULL) {
 		unsigned char *hdr = p1;
 		term->id = id;
-		switch (hdr[2]) {
-		case UAC_INPUT_TERMINAL:
-			if (state->mixer->protocol == UAC_VERSION_1) {
-				struct uac_input_terminal_descriptor *d = p1;
-				term->type = le16_to_cpu(d->wTerminalType);
-				term->channels = d->bNrChannels;
-				term->chconfig = le16_to_cpu(d->wChannelConfig);
-				term->name = d->iTerminal;
-			} else { /* UAC_VERSION_2 */
-				struct uac2_input_terminal_descriptor *d = p1;
+
+		if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
+			switch (hdr[2]) {
+			case UAC_INPUT_TERMINAL:
+				if (protocol == UAC_VERSION_1) {
+					struct uac_input_terminal_descriptor *d = p1;
+
+					term->type = le16_to_cpu(d->wTerminalType);
+					term->channels = d->bNrChannels;
+					term->chconfig = le16_to_cpu(d->wChannelConfig);
+					term->name = d->iTerminal;
+				} else { /* UAC_VERSION_2 */
+					struct uac2_input_terminal_descriptor *d = p1;
+
+					/* call recursively to verify that the
+					 * referenced clock entity is valid */
+					err = check_input_term(state, d->bCSourceID, term);
+					if (err < 0)
+						return err;
+
+					/* save input term properties after recursion,
+					 * to ensure they are not overriden by the
+					 * recursion calls */
+					term->id = id;
+					term->type = le16_to_cpu(d->wTerminalType);
+					term->channels = d->bNrChannels;
+					term->chconfig = le32_to_cpu(d->bmChannelConfig);
+					term->name = d->iTerminal;
+				}
+				return 0;
+			case UAC_FEATURE_UNIT: {
+				/* the header is the same for v1 and v2 */
+				struct uac_feature_unit_descriptor *d = p1;
+
+				id = d->bSourceID;
+				break; /* continue to parse */
+			}
+			case UAC_MIXER_UNIT: {
+				struct uac_mixer_unit_descriptor *d = p1;
+
+				term->type = d->bDescriptorSubtype << 16; /* virtual type */
+				term->channels = uac_mixer_unit_bNrChannels(d);
+				term->chconfig = uac_mixer_unit_wChannelConfig(d, protocol);
+				term->name = uac_mixer_unit_iMixer(d);
+				return 0;
+			}
+			case UAC_SELECTOR_UNIT:
+			case UAC2_CLOCK_SELECTOR: {
+				struct uac_selector_unit_descriptor *d = p1;
+				/* call recursively to retrieve the channel info */
+				err = check_input_term(state, d->baSourceID[0], term);
+				if (err < 0)
+					return err;
+				term->type = d->bDescriptorSubtype << 16; /* virtual type */
+				term->id = id;
+				term->name = uac_selector_unit_iSelector(d);
+				return 0;
+			}
+			case UAC1_PROCESSING_UNIT:
+			case UAC1_EXTENSION_UNIT:
+			/* UAC2_PROCESSING_UNIT_V2 */
+			/* UAC2_EFFECT_UNIT */
+			case UAC2_EXTENSION_UNIT_V2: {
+				struct uac_processing_unit_descriptor *d = p1;
+
+				if (protocol == UAC_VERSION_2 &&
+					hdr[2] == UAC2_EFFECT_UNIT) {
+					/* UAC2/UAC1 unit IDs overlap here in an
+					 * uncompatible way. Ignore this unit for now.
+					 */
+					return 0;
+				}
+
+				if (d->bNrInPins) {
+					id = d->baSourceID[0];
+					break; /* continue to parse */
+				}
+				term->type = d->bDescriptorSubtype << 16; /* virtual type */
+				term->channels = uac_processing_unit_bNrChannels(d);
+				term->chconfig = uac_processing_unit_wChannelConfig(d, protocol);
+				term->name = uac_processing_unit_iProcessing(d, protocol);
+				return 0;
+			}
+			case UAC2_CLOCK_SOURCE: {
+				struct uac_clock_source_descriptor *d = p1;
+
+				term->type = d->bDescriptorSubtype << 16; /* virtual type */
+				term->id = id;
+				term->name = d->iClockSource;
+				return 0;
+			}
+			default:
+				return -ENODEV;
+			}
+		} else { /* UAC_VERSION_3 */
+			switch (hdr[2]) {
+			case UAC_INPUT_TERMINAL: {
+				struct uac3_input_terminal_descriptor *d = p1;
 
 				/* call recursively to verify that the
 				 * referenced clock entity is valid */
···
 				 * recursion calls */
 				term->id = id;
 				term->type = le16_to_cpu(d->wTerminalType);
-				term->channels = d->bNrChannels;
-				term->chconfig = le32_to_cpu(d->bmChannelConfig);
-				term->name = d->iTerminal;
-			}
-			return 0;
-		case UAC_FEATURE_UNIT: {
-			/* the header is the same for v1 and v2 */
-			struct uac_feature_unit_descriptor *d = p1;
-			id = d->bSourceID;
-			break; /* continue to parse */
-		}
-		case UAC_MIXER_UNIT: {
-			struct uac_mixer_unit_descriptor *d = p1;
-			term->type = d->bDescriptorSubtype << 16; /* virtual type */
-			term->channels = uac_mixer_unit_bNrChannels(d);
-			term->chconfig = uac_mixer_unit_wChannelConfig(d, state->mixer->protocol);
-			term->name = uac_mixer_unit_iMixer(d);
-			return 0;
-		}
-		case UAC_SELECTOR_UNIT:
-		case UAC2_CLOCK_SELECTOR: {
-			struct uac_selector_unit_descriptor *d = p1;
-			/* call recursively to retrieve the channel info */
-			err = check_input_term(state, d->baSourceID[0], term);
-			if (err < 0)
-				return err;
-			term->type = d->bDescriptorSubtype << 16; /* virtual type */
-			term->id = id;
-			term->name = uac_selector_unit_iSelector(d);
-			return 0;
-		}
-		case UAC1_PROCESSING_UNIT:
-		case UAC1_EXTENSION_UNIT:
-		/* UAC2_PROCESSING_UNIT_V2 */
-		/* UAC2_EFFECT_UNIT */
-		case UAC2_EXTENSION_UNIT_V2: {
-			struct uac_processing_unit_descriptor *d = p1;
 
-			if (state->mixer->protocol == UAC_VERSION_2 &&
-				hdr[2] == UAC2_EFFECT_UNIT) {
-				/* UAC2/UAC1 unit IDs overlap here in an
-				 * uncompatible way. Ignore this unit for now.
-				 */
+				/* REVISIT: UAC3 IT doesn't have channels/cfg */
+				term->channels = 0;
+				term->chconfig = 0;
+
+				term->name = le16_to_cpu(d->wTerminalDescrStr);
 				return 0;
 			}
+			case UAC3_FEATURE_UNIT: {
+				struct uac3_feature_unit_descriptor *d = p1;
 
-			if (d->bNrInPins) {
-				id = d->baSourceID[0];
+				id = d->bSourceID;
 				break; /* continue to parse */
 			}
-			term->type = d->bDescriptorSubtype << 16; /* virtual type */
-			term->channels = uac_processing_unit_bNrChannels(d);
-			term->chconfig = uac_processing_unit_wChannelConfig(d, state->mixer->protocol);
-			term->name = uac_processing_unit_iProcessing(d, state->mixer->protocol);
-			return 0;
-		}
-		case UAC2_CLOCK_SOURCE: {
-			struct uac_clock_source_descriptor *d = p1;
-			term->type = d->bDescriptorSubtype << 16; /* virtual type */
-			term->id = id;
-			term->name = d->iClockSource;
-			return 0;
-		}
-		default:
-			return -ENODEV;
+			case UAC3_CLOCK_SOURCE: {
+				struct uac3_clock_source_descriptor *d = p1;
+
+				term->type = d->bDescriptorSubtype << 16; /* virtual type */
+				term->id = id;
+				term->name = le16_to_cpu(d->wClockSourceStr);
+				return 0;
+			}
+			default:
+				return -ENODEV;
+			}
 		}
 	}
 	return -ENODEV;
···
 	 * The only property of this unit we are interested in is the
 	 * clock source validity. If that isn't readable, just bail out.
 	 */
-	if (!uac2_control_is_readable(hdr->bmControls,
+	if (!uac_v2v3_control_is_readable(hdr->bmControls,
 				      ilog2(UAC2_CS_CONTROL_CLOCK_VALID)))
 		return 0;
 
···
 	cval->val_type = USB_MIXER_BOOLEAN;
 	cval->control = UAC2_CS_CONTROL_CLOCK_VALID;
 
-	if (uac2_control_is_writeable(hdr->bmControls,
+	if (uac_v2v3_control_is_writeable(hdr->bmControls,
 				      ilog2(UAC2_CS_CONTROL_CLOCK_VALID)))
 		kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
 	else {
···
 				      unitid);
 			return -EINVAL;
 		}
-	} else {
+	} else if (state->mixer->protocol == UAC_VERSION_2) {
 		struct uac2_feature_unit_descriptor *ftr = _ftr;
 		if (hdr->bLength < 6) {
 			usb_audio_err(state->chip,
···
 		if (hdr->bLength < 6 + csize) {
 			usb_audio_err(state->chip,
 				      "unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
+				      unitid);
+			return -EINVAL;
+		}
+	} else { /* UAC_VERSION_3 */
+		struct uac3_feature_unit_descriptor *ftr = _ftr;
+
+		if (hdr->bLength < 7) {
+			usb_audio_err(state->chip,
+				      "unit %u: invalid UAC3_FEATURE_UNIT descriptor\n",
+				      unitid);
+			return -EINVAL;
+		}
+		csize = 4;
+		channels = (ftr->bLength - 7) / 4 - 1;
+		bmaControls = ftr->bmaControls;
+		if (hdr->bLength < 7 + csize) {
+			usb_audio_err(state->chip,
+				      "unit %u: invalid UAC3_FEATURE_UNIT descriptor\n",
 				      unitid);
 			return -EINVAL;
 		}
···
 				build_feature_ctl(state, _ftr, 0, i, &iterm,
 						  unitid, 0);
 		}
-	} else { /* UAC_VERSION_2 */
+	} else { /* UAC_VERSION_2/3 */
 		for (i = 0; i < ARRAY_SIZE(audio_feature_info); i++) {
 			unsigned int ch_bits = 0;
 			unsigned int ch_read_only = 0;
···
 
 				mask = snd_usb_combine_bytes(bmaControls +
 							     csize * (j+1), csize);
-				if (uac2_control_is_readable(mask, i)) {
+				if (uac_v2v3_control_is_readable(mask, i)) {
 					ch_bits |= (1 << j);
-					if (!uac2_control_is_writeable(mask, i))
+					if (!uac_v2v3_control_is_writeable(mask, i))
 						ch_read_only |= (1 << j);
 				}
 			}
···
 			if (ch_bits & 1)
 				build_feature_ctl(state, _ftr, ch_bits, i,
 						  &iterm, unitid, ch_read_only);
-			if (uac2_control_is_readable(master_bits, i))
+			if (uac_v2v3_control_is_readable(master_bits, i))
 				build_feature_ctl(state, _ftr, 0, i, &iterm, unitid,
-						  !uac2_control_is_writeable(master_bits, i));
+						  !uac_v2v3_control_is_writeable(master_bits, i));
 		}
 	}
 
···
 static int parse_audio_unit(struct mixer_build *state, int unitid)
 {
 	unsigned char *p1;
+	int protocol = state->mixer->protocol;
 
 	if (test_and_set_bit(unitid, state->unitbitmap))
 		return 0; /* the unit already visited */
···
 		return -EINVAL;
 	}
 
-	switch (p1[2]) {
-	case UAC_INPUT_TERMINAL:
-		return 0; /* NOP */
-	case UAC_MIXER_UNIT:
-		return parse_audio_mixer_unit(state, unitid, p1);
-	case UAC2_CLOCK_SOURCE:
-		return parse_clock_source_unit(state, unitid, p1);
-	case UAC_SELECTOR_UNIT:
-	case UAC2_CLOCK_SELECTOR:
-		return parse_audio_selector_unit(state, unitid, p1);
-	case UAC_FEATURE_UNIT:
-		return parse_audio_feature_unit(state, unitid, p1);
-	case UAC1_PROCESSING_UNIT:
-	/*   UAC2_EFFECT_UNIT has the same value */
-		if (state->mixer->protocol == UAC_VERSION_1)
-			return parse_audio_processing_unit(state, unitid, p1);
-		else
-			return 0; /* FIXME - effect units not implemented yet */
-	case UAC1_EXTENSION_UNIT:
-	/*   UAC2_PROCESSING_UNIT_V2 has the same value */
-		if (state->mixer->protocol == UAC_VERSION_1)
+	if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
+		switch (p1[2]) {
+		case UAC_INPUT_TERMINAL:
+			return 0; /* NOP */
+		case UAC_MIXER_UNIT:
+			return parse_audio_mixer_unit(state, unitid, p1);
+		case UAC2_CLOCK_SOURCE:
+			return parse_clock_source_unit(state, unitid, p1);
+		case UAC_SELECTOR_UNIT:
+		case UAC2_CLOCK_SELECTOR:
+			return parse_audio_selector_unit(state, unitid, p1);
+		case UAC_FEATURE_UNIT:
+			return parse_audio_feature_unit(state, unitid, p1);
+		case UAC1_PROCESSING_UNIT:
+		/*   UAC2_EFFECT_UNIT has the same value */
+			if (protocol == UAC_VERSION_1)
+				return parse_audio_processing_unit(state, unitid, p1);
+			else
+				return 0; /* FIXME - effect units not implemented yet */
+		case UAC1_EXTENSION_UNIT:
+		/*   UAC2_PROCESSING_UNIT_V2 has the same value */
+			if (protocol == UAC_VERSION_1)
+				return parse_audio_extension_unit(state, unitid, p1);
+			else /* UAC_VERSION_2 */
+				return parse_audio_processing_unit(state, unitid, p1);
+		case UAC2_EXTENSION_UNIT_V2:
 			return parse_audio_extension_unit(state, unitid, p1);
-		else /* UAC_VERSION_2 */
+		default:
+			usb_audio_err(state->chip,
+				"unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
+			return -EINVAL;
+		}
+	} else { /* UAC_VERSION_3 */
+		switch (p1[2]) {
+		case UAC_INPUT_TERMINAL:
+			return 0; /* NOP */
+		case UAC3_MIXER_UNIT:
+			return parse_audio_mixer_unit(state, unitid, p1);
+		case UAC3_CLOCK_SOURCE:
+			return parse_clock_source_unit(state, unitid, p1);
+		case UAC3_CLOCK_SELECTOR:
+			return parse_audio_selector_unit(state, unitid, p1);
+		case UAC3_FEATURE_UNIT:
+			return parse_audio_feature_unit(state, unitid, p1);
+		case UAC3_EFFECT_UNIT:
+			return 0; /* FIXME - effect units not implemented yet */
+		case UAC3_PROCESSING_UNIT:
 			return parse_audio_processing_unit(state, unitid, p1);
-	case UAC2_EXTENSION_UNIT_V2:
-		return parse_audio_extension_unit(state, unitid, p1);
-	default:
-		usb_audio_err(state->chip,
-			"unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
-		return -EINVAL;
+		case UAC3_EXTENSION_UNIT:
+			return parse_audio_extension_unit(state, unitid, p1);
+		default:
+			usb_audio_err(state->chip,
+				"unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
+			return -EINVAL;
+		}
 	}
 }
 
···
 			err = parse_audio_unit(&state, desc->bSourceID);
 			if (err < 0 && err != -EINVAL)
 				return err;
-		} else { /* UAC_VERSION_2 */
+		} else if (mixer->protocol == UAC_VERSION_2) {
 			struct uac2_output_terminal_descriptor *desc = p;
 
 			if (desc->bLength < sizeof(*desc))
···
 
 			/*
 			 * For UAC2, use the same approach to also add the
+			 * clock selectors
+			 */
+			err = parse_audio_unit(&state, desc->bCSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+		} else {  /* UAC_VERSION_3 */
+			struct uac3_output_terminal_descriptor *desc = p;
+
+			if (desc->bLength < sizeof(*desc))
+				continue; /* invalid descriptor? */
+			/* mark terminal ID as visited */
+			set_bit(desc->bTerminalID, state.unitbitmap);
+			state.oterm.id = desc->bTerminalID;
+			state.oterm.type = le16_to_cpu(desc->wTerminalType);
+			state.oterm.name = le16_to_cpu(desc->wTerminalDescrStr);
+			err = parse_audio_unit(&state, desc->bSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+
+			/*
+			 * For UAC3, use the same approach to also add the
 			 * clock selectors
 			 */
 			err = parse_audio_unit(&state, desc->bCSourceID);
···
 		break;
 	case UAC_VERSION_2:
 		mixer->protocol = UAC_VERSION_2;
+		break;
+	case UAC_VERSION_3:
+		mixer->protocol = UAC_VERSION_3;
 		break;
 	}
 

sound/usb/stream.c

···
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
 
 #include <sound/core.h>
 #include <sound/pcm.h>
···
 	return chmap;
 }
 
+/* UAC3 device stores channels information in Cluster Descriptors */
+static struct
+snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor
+								*cluster)
+{
+	unsigned int channels = cluster->bNrChannels;
+	struct snd_pcm_chmap_elem *chmap;
+	void *p = cluster;
+	int len, c;
+
+	if (channels > ARRAY_SIZE(chmap->map))
+		return NULL;
+
+	chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
+	if (!chmap)
+		return NULL;
+
+	len = le16_to_cpu(cluster->wLength);
+	c = 0;
+	p += sizeof(struct uac3_cluster_header_descriptor);
+
+	while (((p - (void *)cluster) < len) && (c < channels)) {
+		struct uac3_cluster_segment_descriptor *cs_desc = p;
+		u16 cs_len;
+		u8 cs_type;
+
+		cs_len = le16_to_cpu(cs_desc->wLength);
+		cs_type = cs_desc->bSegmentType;
+
+		if (cs_type == UAC3_CHANNEL_INFORMATION) {
+			struct uac3_cluster_information_segment_descriptor *is = p;
+			unsigned char map;
+
+			/*
+			 * TODO: this conversion is not complete, update it
+			 * after adding UAC3 values to asound.h
+			 */
+			switch (is->bChPurpose) {
+			case UAC3_CH_MONO:
+				map = SNDRV_CHMAP_MONO;
+				break;
+			case UAC3_CH_LEFT:
+			case UAC3_CH_FRONT_LEFT:
+			case UAC3_CH_HEADPHONE_LEFT:
+				map = SNDRV_CHMAP_FL;
+				break;
+			case UAC3_CH_RIGHT:
+			case UAC3_CH_FRONT_RIGHT:
+			case UAC3_CH_HEADPHONE_RIGHT:
+				map = SNDRV_CHMAP_FR;
+				break;
+			case UAC3_CH_FRONT_CENTER:
+				map = SNDRV_CHMAP_FC;
+				break;
+			case UAC3_CH_FRONT_LEFT_OF_CENTER:
+				map = SNDRV_CHMAP_FLC;
+				break;
+			case UAC3_CH_FRONT_RIGHT_OF_CENTER:
+				map = SNDRV_CHMAP_FRC;
+				break;
+			case UAC3_CH_SIDE_LEFT:
+				map = SNDRV_CHMAP_SL;
+				break;
+			case UAC3_CH_SIDE_RIGHT:
+				map = SNDRV_CHMAP_SR;
+				break;
+			case UAC3_CH_BACK_LEFT:
+				map = SNDRV_CHMAP_RL;
+				break;
+			case UAC3_CH_BACK_RIGHT:
+				map = SNDRV_CHMAP_RR;
+				break;
+			case UAC3_CH_BACK_CENTER:
+				map = SNDRV_CHMAP_RC;
+				break;
+			case UAC3_CH_BACK_LEFT_OF_CENTER:
+				map = SNDRV_CHMAP_RLC;
+				break;
+			case UAC3_CH_BACK_RIGHT_OF_CENTER:
+				map = SNDRV_CHMAP_RRC;
+				break;
+			case UAC3_CH_TOP_CENTER:
+				map = SNDRV_CHMAP_TC;
+				break;
+			case UAC3_CH_TOP_FRONT_LEFT:
+				map = SNDRV_CHMAP_TFL;
+				break;
+			case UAC3_CH_TOP_FRONT_RIGHT:
+				map = SNDRV_CHMAP_TFR;
+				break;
+			case UAC3_CH_TOP_FRONT_CENTER:
+				map = SNDRV_CHMAP_TFC;
+				break;
+			case UAC3_CH_TOP_FRONT_LOC:
+				map = SNDRV_CHMAP_TFLC;
+				break;
+			case UAC3_CH_TOP_FRONT_ROC:
+				map = SNDRV_CHMAP_TFRC;
+				break;
+			case UAC3_CH_TOP_SIDE_LEFT:
+				map = SNDRV_CHMAP_TSL;
+				break;
+			case UAC3_CH_TOP_SIDE_RIGHT:
+				map = SNDRV_CHMAP_TSR;
+				break;
+			case UAC3_CH_TOP_BACK_LEFT:
+				map = SNDRV_CHMAP_TRL;
+				break;
+			case UAC3_CH_TOP_BACK_RIGHT:
+				map = SNDRV_CHMAP_TRR;
+				break;
+			case UAC3_CH_TOP_BACK_CENTER:
+				map = SNDRV_CHMAP_TRC;
+				break;
+			case UAC3_CH_BOTTOM_CENTER:
+				map = SNDRV_CHMAP_BC;
+				break;
+			case UAC3_CH_LOW_FREQUENCY_EFFECTS:
+				map = SNDRV_CHMAP_LFE;
+				break;
+			case UAC3_CH_LFE_LEFT:
+				map = SNDRV_CHMAP_LLFE;
+				break;
+			case UAC3_CH_LFE_RIGHT:
+				map = SNDRV_CHMAP_RLFE;
+				break;
+			case UAC3_CH_RELATIONSHIP_UNDEFINED:
+			default:
+				map = SNDRV_CHMAP_UNKNOWN;
+				break;
+			}
+			chmap->map[c++] = map;
+		}
+		p += cs_len;
+	}
+
+	if (channels < c)
+		pr_err("%s: channel number mismatch\n", __func__);
+
+	chmap->channels = channels;
+
+	for (; c < channels; c++)
+		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
+
+	return chmap;
+}
+
 /*
  * add this endpoint to the chip instance.
  * if a stream with the same endpoint already exists, append to it.
···
 	return NULL;
 }
 
-static struct uac2_output_terminal_descriptor *
-	snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
-						int terminal_id)
+static void *
+snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+					int terminal_id)
 {
+	/* OK to use with both UAC2 and UAC3 */
 	struct uac2_output_terminal_descriptor *term = NULL;
 
 	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
···
 	struct usb_host_interface *alts;
 	struct usb_interface_descriptor *altsd;
 	int i, altno, err, stream;
-	unsigned int format = 0, num_channels = 0;
+	u64 format = 0;
+	unsigned int num_channels = 0;
 	struct audioformat *fp = NULL;
 	int num, protocol, clock = 0;
-	struct uac_format_type_i_continuous_descriptor *fmt;
+	struct uac_format_type_i_continuous_descriptor *fmt = NULL;
+	struct snd_pcm_chmap_elem *chmap_v3 = NULL;
 	unsigned int chconfig;
 
 	dev = chip->dev;
···
 				iface_no, altno, as->bTerminalLink);
 			continue;
 		}
-		}
 
-		/* get format type */
-		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_FORMAT_TYPE);
-		if (!fmt) {
+		case UAC_VERSION_3: {
+			struct uac3_input_terminal_descriptor *input_term;
+			struct uac3_output_terminal_descriptor *output_term;
+			struct uac3_as_header_descriptor *as;
+			struct uac3_cluster_header_descriptor *cluster;
+			struct uac3_hc_descriptor_header hc_header;
+			u16 cluster_id, wLength;
+
+			as = snd_usb_find_csint_desc(alts->extra,
+							alts->extralen,
+							NULL, UAC_AS_GENERAL);
+
+			if (!as) {
+				dev_err(&dev->dev,
+					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+					iface_no, altno);
+				continue;
+			}
+
+			if (as->bLength < sizeof(*as)) {
+				dev_err(&dev->dev,
+					"%u:%d : invalid UAC_AS_GENERAL desc\n",
+					iface_no, altno);
+				continue;
+			}
+
+			cluster_id = le16_to_cpu(as->wClusterDescrID);
+			if (!cluster_id) {
+				dev_err(&dev->dev,
+					"%u:%d : no cluster descriptor\n",
+					iface_no, altno);
+				continue;
+			}
+
+			/*
+			 * Get number of channels and channel map through
+			 * High Capability Cluster Descriptor
+			 *
+			 * First step: get High Capability header and
+			 * read size of Cluster Descriptor
+			 */
+			err = snd_usb_ctl_msg(chip->dev,
+					usb_rcvctrlpipe(chip->dev, 0),
+					UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+					USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+					cluster_id,
+					snd_usb_ctrl_intf(chip),
+					&hc_header, sizeof(hc_header));
+			if (err < 0)
+				return err;
+			else if (err != sizeof(hc_header)) {
+				dev_err(&dev->dev,
+					"%u:%d : can't get High Capability descriptor\n",
+					iface_no, altno);
+				return -EIO;
+			}
+
+			/*
+			 * Second step: allocate needed amount of memory
+			 * and request Cluster Descriptor
+			 */
+			wLength = le16_to_cpu(hc_header.wLength);
+			cluster = kzalloc(wLength, GFP_KERNEL);
+			if (!cluster)
+				return -ENOMEM;
+			err = snd_usb_ctl_msg(chip->dev,
+					usb_rcvctrlpipe(chip->dev, 0),
+					UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+					USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+					cluster_id,
+					snd_usb_ctrl_intf(chip),
+					cluster, wLength);
+			if (err < 0) {
+				kfree(cluster);
+				return err;
+			} else if (err != wLength) {
+				dev_err(&dev->dev,
+					"%u:%d : can't get Cluster Descriptor\n",
+					iface_no, altno);
+				kfree(cluster);
+				return -EIO;
+			}
+
+			num_channels = cluster->bNrChannels;
+			chmap_v3 = convert_chmap_v3(cluster);
+
+			kfree(cluster);
+
+			format = le64_to_cpu(as->bmFormats);
+
+			/* lookup the terminal associated to this interface
+			 * to extract the clock */
+			input_term = snd_usb_find_input_terminal_descriptor(
+							chip->ctrl_intf,
+							as->bTerminalLink);
+
+			if (input_term) {
+				clock = input_term->bCSourceID;
+				break;
+			}
+
+			output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
+									      as->bTerminalLink);
+			if (output_term) {
+				clock = output_term->bCSourceID;
+				break;
+			}
+
 			dev_err(&dev->dev,
-				"%u:%d : no UAC_FORMAT_TYPE desc\n",
-				iface_no, altno);
+				"%u:%d : bogus bTerminalLink %d\n",
+				iface_no, altno, as->bTerminalLink);
 			continue;
 		}
-		if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8)) ||
-		    ((protocol == UAC_VERSION_2) && (fmt->bLength < 6))) {
-			dev_err(&dev->dev,
-				"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
-				iface_no, altno);
-			continue;
 		}
 
-		/*
-		 * Blue Microphones workaround: The last altsetting is identical
-		 * with the previous one, except for a larger packet size, but
-		 * is actually a mislabeled two-channel setting; ignore it.
-		 */
-		if (fmt->bNrChannels == 1 &&
-		    fmt->bSubframeSize == 2 &&
-		    altno == 2 && num == 3 &&
-		    fp && fp->altsetting == 1 && fp->channels == 1 &&
-		    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
-		    protocol == UAC_VERSION_1 &&
-		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
+		if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
+			/* get format type */
+			fmt = snd_usb_find_csint_desc(alts->extra,
+						      alts->extralen,
+						      NULL, UAC_FORMAT_TYPE);
+			if (!fmt) {
+				dev_err(&dev->dev,
+					"%u:%d : no UAC_FORMAT_TYPE desc\n",
+					iface_no, altno);
+				continue;
+			}
+			if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8))
+					|| ((protocol == UAC_VERSION_2) &&
+							(fmt->bLength < 6))) {
+				dev_err(&dev->dev,
+					"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
+					iface_no, altno);
+				continue;
+			}
+
+			/*
+			 * Blue Microphones workaround: The last altsetting is
+			 * identical with the previous one, except for a larger
+			 * packet size, but is actually a mislabeled two-channel
+			 * setting; ignore it.
+			 */
+			if (fmt->bNrChannels == 1 &&
+			    fmt->bSubframeSize == 2 &&
+			    altno == 2 && num == 3 &&
+			    fp && fp->altsetting == 1 && fp->channels == 1 &&
+			    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
+			    protocol == UAC_VERSION_1 &&
+			    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
 							fp->maxpacksize * 2)
-			continue;
+				continue;
+		}
 
 		fp = kzalloc(sizeof(*fp), GFP_KERNEL);
 		if (!fp)
···
 		snd_usb_audioformat_attributes_quirk(chip, fp, stream);
 
 		/* ok, let's parse further... */
-		if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
-			kfree(fp->rate_table);
-			kfree(fp);
-			fp = NULL;
-			continue;
+		if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
+			if (snd_usb_parse_audio_format(chip, fp, format,
+							fmt, stream) < 0) {
+				kfree(fp->rate_table);
+				kfree(fp);
+				fp = NULL;
+				continue;
+			}
+		} else {
+			struct uac3_as_header_descriptor *as;
+
+			as = snd_usb_find_csint_desc(alts->extra,
+						     alts->extralen,
+						     NULL, UAC_AS_GENERAL);
+
+			if (snd_usb_parse_audio_format_v3(chip, fp, as,
+								stream) < 0) {
+				kfree(fp->rate_table);
+				kfree(fp);
+				fp = NULL;
+				continue;
+			}
 		}
 
 		/* Create chmap */
 		if (fp->channels != num_channels)
 			chconfig = 0;
-		fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
+
+		if (protocol == UAC_VERSION_3)
+			fp->chmap = chmap_v3;
+		else
+			fp->chmap = convert_chmap(fp->channels, chconfig,
+						  protocol);
 
 		dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
 		err = snd_usb_add_audio_stream(chip, stream, fp);