samples: Bluetooth: BAP: Broadcast sink use new USB stack

Refactor the USB of the BAP broadcast sink to use the new
USB stack.

Signed-off-by: Emil Gydesen <[email protected]>

samples/bluetooth/bap_broadcast_sink/CMakeLists.txt

@@ -2,14 +2,16 @@
 
 cmake_minimum_required(VERSION 3.20.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(bap_unicast_server)
+project(bap_unicast_sink)
 
 target_sources(app PRIVATE
   src/main.c
   src/stream_rx.c
 )
 
-zephyr_sources_ifdef(CONFIG_LIBLC3 src/lc3.c)
-zephyr_sources_ifdef(CONFIG_USB_DEVICE_AUDIO src/usb.c)
+target_sources_ifdef(CONFIG_ENABLE_LC3 app PRIVATE src/lc3.c)
 
-zephyr_library_include_directories(${ZEPHYR_BASE}/samples/bluetooth)
+if (CONFIG_USE_USB_AUDIO_OUTPUT)
+  include(${ZEPHYR_BASE}/samples/subsys/usb/common/common.cmake)
+  target_sources(app PRIVATE src/usb.c)
+endif()

samples/bluetooth/bap_broadcast_sink/Kconfig

@@ -55,8 +55,8 @@ config ENABLE_LC3
 config USE_USB_AUDIO_OUTPUT
 	bool "Use USB Audio as output"
 	depends on ENABLE_LC3
-	select USB_DEVICE_STACK
-	select USB_DEVICE_AUDIO
+	select USB_DEVICE_STACK_NEXT
+	select USBD_AUDIO2_CLASS
 	select RING_BUFFER
 	help
 	  Enables USB audio as output as a USB peripheral. This does not support providing USB
@@ -87,4 +87,9 @@ config INFO_REPORTING_INTERVAL
 	  Determines how often information about received data is logged.
 	  Set to 0 to disable reporting.
 
+# Source common USB sample options used to initialize new experimental USB device stack.
+# The scope of these options is limited to USB samples in project tree,
+# you cannot use them in your own application.
+source "samples/subsys/usb/common/Kconfig.sample_usbd"
+
 source "Kconfig.zephyr"

samples/bluetooth/bap_broadcast_sink/app.overlay

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <dt-bindings/usb/audio.h>
+
+/ {
+	uac2_microphone: usb_audio2 {
+		compatible = "zephyr,uac2";
+		status = "okay";
+		full-speed;
+		audio-function = <AUDIO_FUNCTION_MICROPHONE>;
+
+		/* Clock supporting 48KHz
+		 *
+		 * Since the incoming audio may be between 8 and 48 KHz, we always upsample to 48KHz
+		 */
+		uac_aclk: aclk {
+			compatible = "zephyr,uac2-clock-source";
+			clock-type = "internal-programmable";
+			frequency-control = "read-only";
+			sampling-frequencies = <48000>;
+		};
+
+		/* The out_terminal supports the incoming Bluetooth LE Audio over ISO
+		 * and treats it as a microphone towards the USB host
+		 */
+		out_terminal: out_terminal {
+			compatible = "zephyr,uac2-input-terminal";
+			clock-source = <&uac_aclk>;
+			terminal-type = <INPUT_TERMINAL_MICROPHONE>;
+			front-left;
+			front-right;
+		};
+
+		/* USB Audio terminal from USB device to USB host */
+		in_terminal: in_terminal {
+			compatible = "zephyr,uac2-output-terminal";
+			data-source = <&out_terminal>;
+			clock-source = <&uac_aclk>;
+			terminal-type = <USB_TERMINAL_STREAMING>;
+		};
+
+		as_iso_in: in_interface {
+			compatible = "zephyr,uac2-audio-streaming";
+			linked-terminal = <&in_terminal>;
+			subslot-size = <2>;
+			bit-resolution = <16>;
+		};
+	};
+};

samples/bluetooth/bap_broadcast_sink/boards/nrf52833dk_nrf52833.conf

@@ -1,3 +1,3 @@
 # Use USB Audio as audio sink
 CONFIG_USE_USB_AUDIO_OUTPUT=y
-CONFIG_USB_DEVICE_PRODUCT="USB Broadcast Sink"
+CONFIG_SAMPLE_USBD_PRODUCT="USB Broadcast Sink sample"

samples/bluetooth/bap_broadcast_sink/boards/nrf52833dk_nrf52833.overlay

@@ -1,15 +1,7 @@
-zephyr_udc0: &usbd {
-	compatible = "nordic,nrf-usbd";
-	status = "okay";
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-	hs_0: hs_0 {
-		compatible = "usb-audio-hs";
-		mic-feature-mute;
-		mic-channel-l;
-		mic-channel-r;
-
-		hp-feature-mute;
-		hp-channel-l;
-		hp-channel-r;
-	};
-};
+#include "../app.overlay"

samples/bluetooth/bap_broadcast_sink/boards/nrf52840dk_nrf52840.conf

@@ -0,0 +1,3 @@
+# Use USB Audio as audio sink
+CONFIG_USE_USB_AUDIO_OUTPUT=y
+CONFIG_SAMPLE_USBD_PRODUCT="USB Broadcast Sink sample"

samples/bluetooth/bap_broadcast_sink/boards/nrf52840dk_nrf52840.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "../app.overlay"

samples/bluetooth/bap_broadcast_sink/boards/nrf52840dongle_nrf52840.conf

@@ -1,3 +1,5 @@
 # Use USB Audio as audio sink
 CONFIG_USE_USB_AUDIO_OUTPUT=y
-CONFIG_USB_DEVICE_PRODUCT="USB Broadcast Sink"
+CONFIG_SAMPLE_USBD_PRODUCT="USB Broadcast Sink sample"
+
+CONFIG_BOARD_SERIAL_BACKEND_CDC_ACM=n

samples/bluetooth/bap_broadcast_sink/boards/nrf52840dongle_nrf52840.overlay

@@ -1,15 +1,7 @@
-zephyr_udc0: &usbd {
-	compatible = "nordic,nrf-usbd";
-	status = "okay";
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-	hs_0: hs_0 {
-		compatible = "usb-audio-hs";
-		mic-feature-mute;
-		mic-channel-l;
-		mic-channel-r;
-
-		hp-feature-mute;
-		hp-channel-l;
-		hp-channel-r;
-	};
-};
+#include "../app.overlay"

samples/bluetooth/bap_broadcast_sink/boards/nrf5340_audio_dk_nrf5340_cpuapp.conf

@@ -1,3 +1,3 @@
 # Use USB Audio as audio sink
 CONFIG_USE_USB_AUDIO_OUTPUT=y
-CONFIG_USB_DEVICE_PRODUCT="USB Broadcast Sink"
+CONFIG_SAMPLE_USBD_PRODUCT="USB Broadcast Sink sample"

samples/bluetooth/bap_broadcast_sink/boards/nrf5340_audio_dk_nrf5340_cpuapp.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "../app.overlay"

samples/bluetooth/bap_broadcast_sink/boards/nrf5340dk_nrf5340_cpuapp.conf

@@ -1,3 +1,3 @@
 # Use USB Audio as audio sink
 CONFIG_USE_USB_AUDIO_OUTPUT=y
-CONFIG_USB_DEVICE_PRODUCT="USB Broadcast Sink"
+CONFIG_SAMPLE_USBD_PRODUCT="USB Broadcast Sink sample"

samples/bluetooth/bap_broadcast_sink/boards/nrf5340dk_nrf5340_cpuapp.overlay

@@ -1,15 +1,7 @@
-zephyr_udc0: &usbd {
-	compatible = "nordic,nrf-usbd";
-	status = "okay";
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
-	hs_0: hs_0 {
-		compatible = "usb-audio-hs";
-		mic-feature-mute;
-		mic-channel-l;
-		mic-channel-r;
-
-		hp-feature-mute;
-		hp-channel-l;
-		hp-channel-r;
-	};
-};
+#include "../app.overlay"

samples/bluetooth/bap_broadcast_sink/src/lc3.c

@@ -65,7 +65,6 @@ static K_FIFO_DEFINE(lc3_in_fifo);
  */
 static struct stream_rx *usb_left_stream;
 static struct stream_rx *usb_right_stream;
-static size_t rx_streaming_cnt;
 
 static int init_lc3_decoder(struct stream_rx *stream, uint32_t lc3_frame_duration_us,
 			    uint32_t lc3_freq_hz)
@@ -92,15 +91,14 @@ static int init_lc3_decoder(struct stream_rx *stream, uint32_t lc3_frame_duratio
 	/* Create the decoder instance. This shall complete before stream_started() is called. */
 	stream->lc3_decoder =
 		lc3_setup_decoder(lc3_frame_duration_us, lc3_freq_hz,
-				  IS_ENABLED(CONFIG_USB_DEVICE_AUDIO) ? USB_SAMPLE_RATE_HZ : 0,
+				  IS_ENABLED(CONFIG_USE_USB_AUDIO_OUTPUT) ? USB_SAMPLE_RATE_HZ : 0,
 				  &stream->lc3_decoder_mem);
 	if (stream->lc3_decoder == NULL) {
 		LOG_ERR("Failed to setup LC3 decoder - wrong parameters?\n");
 		return -EINVAL;
 	}
 
 	LOG_INF("Initialized LC3 decoder for %p", stream);
-	rx_streaming_cnt++;
 
 	return 0;
 }
@@ -152,7 +150,7 @@ static bool decode_frame(struct lc3_data *data, size_t frame_cnt)
 static int get_lc3_chan_alloc_from_index(const struct stream_rx *stream, uint8_t index,
 					 enum bt_audio_location *chan_alloc)
 {
-#if defined(CONFIG_USB_DEVICE_AUDIO)
+#if defined(CONFIG_USE_USB_AUDIO_OUTPUT)
 	const bool has_left = (stream->lc3_chan_allocation & BT_AUDIO_LOCATION_FRONT_LEFT) != 0;
 	const bool has_right = (stream->lc3_chan_allocation & BT_AUDIO_LOCATION_FRONT_RIGHT) != 0;
 	const bool is_mono = stream->lc3_chan_allocation == BT_AUDIO_LOCATION_MONO_AUDIO;
@@ -174,9 +172,9 @@ static int get_lc3_chan_alloc_from_index(const struct stream_rx *stream, uint8_t
 	}
 
 	return 0;
-#else  /* !CONFIG_USB_DEVICE_AUDIO */
+#else  /* !CONFIG_USE_USB_AUDIO_OUTPUT */
 	return -EINVAL;
-#endif /* CONFIG_USB_DEVICE_AUDIO */
+#endif /* CONFIG_USE_USB_AUDIO_OUTPUT */
 }
 
 static size_t decode_frame_block(struct lc3_data *data, size_t frame_cnt)
@@ -192,7 +190,7 @@ static size_t decode_frame_block(struct lc3_data *data, size_t frame_cnt)
 		if (decode_frame(data, frame_cnt + decoded_frames)) {
 			decoded_frames++;
 
-			if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+			if (IS_ENABLED(CONFIG_USE_USB_AUDIO_OUTPUT)) {
 				enum bt_audio_location chan_alloc;
 				int err;
 
@@ -223,7 +221,7 @@ static size_t decode_frame_block(struct lc3_data *data, size_t frame_cnt)
 			/* If decoding failed, we clear the data to USB as it would contain
 			 * invalid data
 			 */
-			if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+			if (IS_ENABLED(CONFIG_USE_USB_AUDIO_OUTPUT)) {
 				usb_clear_frames_to_usb();
 			}
 
@@ -379,7 +377,7 @@ int lc3_enable(struct stream_rx *stream)
 		}
 	}
 
-	if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+	if (IS_ENABLED(CONFIG_USE_USB_AUDIO_OUTPUT)) {
 		if ((stream->lc3_chan_allocation & BT_AUDIO_LOCATION_FRONT_LEFT) != 0) {
 			if (usb_left_stream == NULL) {
 				LOG_INF("Setting USB left stream to %p", stream);
@@ -404,12 +402,11 @@ int lc3_enable(struct stream_rx *stream)
 
 int lc3_disable(struct stream_rx *stream)
 {
-	if (rx_streaming_cnt == 0 || stream->lc3_decoder == NULL) {
+	if (stream->lc3_decoder == NULL) {
 		return -EINVAL;
 	}
 
 	stream->lc3_decoder = NULL;
-	rx_streaming_cnt--;
 
 	if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
 		if (usb_left_stream == stream) {
@@ -488,8 +485,3 @@ int lc3_init(void)
 
 	return 0;
 }
-
-size_t lc3_get_rx_streaming_cnt(void)
-{
-	return rx_streaming_cnt;
-}

samples/bluetooth/bap_broadcast_sink/src/lc3.h

@@ -35,19 +35,12 @@
 
 #include "stream_rx.h"
 
-#define LC3_MAX_SAMPLE_RATE_HZ     48000U
+#define LC3_MAX_SAMPLE_RATE_HZ     48000U /* Limit to 16KHz for now */
 #define LC3_MAX_FRAME_DURATION_US  10000U
 #define LC3_MAX_NUM_SAMPLES_MONO                                                                   \
 	((LC3_MAX_FRAME_DURATION_US * LC3_MAX_SAMPLE_RATE_HZ) / USEC_PER_SEC)
 #define LC3_MAX_NUM_SAMPLES_STEREO (LC3_MAX_NUM_SAMPLES_MONO * 2U)
 
-/**
- * @brief Returns the number of active streams using an LC3 codec
- *
- * @return the number of active streams using an LC3 codec
- */
-size_t lc3_get_rx_streaming_cnt(void);
-
 /**
  * @brief Enables LC3 for a stream
  *

samples/bluetooth/bap_broadcast_sink/src/main.c

@@ -890,7 +890,7 @@ static int init(void)
 		lc3_init();
 	}
 
-	if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+	if (IS_ENABLED(CONFIG_USE_USB_AUDIO_OUTPUT)) {
 		usb_init();
 	}