samples: Add USB Audio to broadcast audio source

Adds support for using a connected host to
broadcast audio via USB Audio.

Sets BT_DATA_BROADCAST_NAME to BT_DEVICE_NAME
for discovery on receivers not using BT_DEVICE_NAME.

Offload LC3 encoding to separate thread.

Limits streams to one channel.

Signed-off-by: Lars Knudsen <[email protected]>

samples/bluetooth/broadcast_audio_source/Kconfig

@@ -28,4 +28,13 @@ config ENABLE_LC3
 	select LIBLC3
 	select FPU
 
+config USE_USB_AUDIO_INPUT
+	bool "Use USB Audio as input"
+	# By default, use the USB Audio path is disabled.
+	default n
+	depends on ENABLE_LC3
+	select USB_DEVICE_STACK
+	select USB_DEVICE_AUDIO
+	select RING_BUFFER
+
 source "Kconfig.zephyr"

samples/bluetooth/broadcast_audio_source/boards/nrf5340_audio_dk_nrf5340_cpuapp.conf

@@ -1,4 +1,8 @@
-# The LC3 codec uses a large amount of stack. This app runs the codec in the work-queue, hence
-# inctease stack size for that thread.
-CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096
 CONFIG_MAIN_STACK_SIZE=4096
+
+# Use USB Audio as input
+CONFIG_USE_USB_AUDIO_INPUT=y
+CONFIG_USB_DEVICE_PRODUCT="Zephyr Broadcast Source"
+
+# Two streams in one subgroup (stereo)
+CONFIG_BT_BAP_BROADCAST_SRC_SUBGROUP_COUNT=1

samples/bluetooth/broadcast_audio_source/prj.conf

@@ -13,5 +13,3 @@ CONFIG_BT_ISO_TX_BUF_COUNT=4
 CONFIG_BT_ISO_TX_MTU=60
 
 CONFIG_BT_DEVICE_NAME="Broadcast Audio Source"
-
-CONFIG_BT_TINYCRYPT_ECC=y