How to enable UAC gadget?

Yocto
, , ,
1

Hey everyone!

I want to use the UAC Gadget function on the Genio 1200.
How can I enable it? Any recommendations for this?

Thanks a bunch!

3

Please follow the steps: (tested on kernel v6.6)

  1. Enable UAC related kernel option

    CONFIG_USB_CONFIGFS_F_UAC1=y
CONFIG_USB_CONFIGFS_F_UAC2=y
CONFIG_USB_CONFIGFS_F_UAC1_LEGACY=y
CONFIG_USB_CONFIGFS_F_ACC=y
CONFIG_USB_CONFIGFS_F_AUDIO_SRC=y

  2. Add UAC config to USB gadget via console (UART/SSH) on EVK

    cd  /sys/kernel/config/usb_gadget/g1
echo "" > UDC
rm -rf configs/c.1/ffs.adb           # remove adb function
rm -rf configs/c.1/rndis.usb0        # remove rndis function
rm -rf configs/c.1/uac2.usb0         # remove previous uac2 function
echo "0x046D" > idVendor
echo "0x087C" > idProduct
echo "0x0010" > bcdDevice
echo "0xef" > bDeviceClass
echo "0x02" > bDeviceSubClass
echo "0x01" > bDeviceProtocol
mkdir strings/0x409 
echo "0123456789ABCDEF" > strings/0x409/serialnumber
echo "Mediatek Inc." > strings/0x409/manufacturer
echo "uac gadget" > strings/0x409/product

# UAC2
mkdir -p functions/uac2.usb0
echo 8000,16000,44100,48000,96000 > functions/uac2.usb0/c_srate
echo 2 > functions/uac2.usb0/c_ssize            # capture 2 bytes, 16bits
echo 0x3 > functions/uac2.usb0/c_chmask         # 0x3 stereo(FL+FR)
echo 1 > functions/uac2.usb0/c_mute_present
echo 1 > functions/uac2.usb0/c_volume_present
echo -5120 > functions/uac2.usb0/c_volume_min
echo 8000,16000,44100,48000,96000 > functions/uac2.usb0/p_srate
echo 2 > functions/uac2.usb0/p_ssize            # playback 2 bytes, 16bits
echo 0x3 > functions/uac2.usb0/p_chmask         # 0x3 stereo(FL+FR)
echo 1 > functions/uac2.usb0/p_mute_present
echo 1 > functions/uac2.usb0/p_volume_present
echo -5120 > functions/uac2.usb0/p_volume_min
ln -s functions/uac2.usb0/ configs/c.1            # bind uac2 function

echo $(ls /sys/class/udc | awk 'NR==1') > UDC # bind  to UDC
echo "uac setup done!"

  3. Connect USB-0 to Windows PC, a USB audio device “Source/Sink” should be registered.

  4. Play audio on EVK, receive(hear) on PC

    • [PC] Windows → sound setting → record → choose the UAC microphone → content → receive → check “Listen to this device”
    • [EVK]
      • aplay --list-devices to find the UAC2 Gadget.
      • The example shows UAC2Gadget is listed on card 1, device 0
      card 1: UAC2Gadget [UAC2_Gadget], device 0: UAC2 PCM [UAC2 PCM]
  	Subdevices: 1/1
  	Subdevice #0: subdevice #0
      • aplay piano2.wav -r 48000 -c 2 -D hw:1,0
    • [PC] Now you can hear the sound on your PC.

  5. Play audio on PC, record on EVK

    • [PC] Windows → choose sound output device to UAC sound device
    • [PC] Play some music on PC
    • [EVK] arecord -D hw:1,0 -f S16_LE -d 10 uac.wav to get 10sec sound recording from soundcard 1, device 0.