This version (27 Jul 2020 06:52) was approved by sullivan liu.
Table of Contents
USB Gadget Audio
This page provides how to use the USB Gadget Audio on ADSP-SC5XX board which makes the the Board as an audio card, and it will include the below test:
- USB gadget Audio Class 1.0
- USB Gadget Audio Class 2.0
Hardware Configuration
Connect the USB micro-B plug cable into the USB HS/OTG Device port, as showing below:
Software Configuration
On the Yocto, Configure the linux-kernel as below to set the USB controller in Gadget only mode, and enable the USB Gadget Audio relevant options.
Package Configuration
Add the alsa-utils and alsa-lib packages in the filesystem, they're enabled in adsp-sc5xx-full image by default.
Enable alsa-lib and alsa-utils support
vim build/conf/local.conf IMAGE_INSTALL_append = "alsa-utils alsa-lib"
Then run “bitbake adsp-sc5xx-minimal -C compile” or “bitbake adsp-sc5xx-full -C compile” to generate the filesystem.
Kernel Configuration
$ bitbake linux-adi -c menuconfig
Configure the USB drivers to Gadget only mode (or Dual role mode )
Device Drivers --->
[*] USB support --->
<*> Support for Host-side USB
<*> Inventra Highspeed Dual Role Controller
MUSB Mode Selection (Dual role mode) --->
*** Platform Glue Layer ***
<*> ADI
*** MUSB DMA mode ***
[N] Disable DMA (always use PIO)
[*] Inventra
<*> USB Gadget Support --->
Configure the Gadget Audio support
- Enable the corresponding sound card and the USB sound device feature:
Device Drivers --->
<*> USB support
<*> Support for Host-side USB
<*> Sound card support --->
<*> Advanced Linux Sound Architecture --->
[*] USB sound devices
- For Class 1.0
Device Drivers --->
[*] USB support --->
<*> USB Gadget Support --->
<M> USB Gadget precomposed configurations
[M] Audio Gadget
[*] UAC 1.0
[*] UAC 1.0(Legacy
- For Class 2.0
Device Drivers --->
[*] USB support --->
<*> USB Gadget Support --->
<M> USB Gadget precomposed configurations
[M] Audio Gadget
[ ] UAC 1.0
[ ] UAC 1.0(Legacy
Example Usage
Class 1.0
Ez-Kit target board
root@adsp-sc589-ezkit:~# ls /dev/snd/ controlC0 pcmC0D0p pcmC0D1c timer root@adsp-sc589-ezkit:~# modprobe g_audio modprobe g_audio fn_play=/dev/snd/pcmC0D0p fn_cap=/dev/snd/pcmC0D1c g_audio gadget: Hardware params: access 3, format 2, channels 2, rate 48000 g_audio gadget: Linux USB Audio Gadget, version: Feb 2, 2012 g_audio gadget: g_audio ready g_audio gadget: high-speed config #1: Linux USB Audio Gadget
On the Linux-Host PC
With following command you should be able to see the USB Gadget Audio device is there on your HOST:
test@madara:~$ lsusb Bus 002 Device 033: ID 1d6b:0101 Linux Foundation Audio Gadget
Then we list the available sound card on host PC, to decide which sound card is associated with EZKIT board
test@madara:~$ cat /proc/asound/cards 0 [PCH ]: HDA-Intel - HDA Intel PCH HDA Intel PCH at 0xf7d00000 irq 28 1 [Gadget ]: USB-Audio - Linux USB Audio Gadget Linux 4.19.0-yocto-standard with musb-hdrc Linux USB Audio Gadget at usb-0000:0
test@madara:~$ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: Gadget [Linux USB Audio Gadget], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0
From above list information we can see sound card 1,device 0 is the one associated with USB Gadget Audio device, then we play sound file to this card. In this example, we are using aplay to play a PCM wave audio file: sample_s16_le.wav
test@madara:~$ aplay -D hw:1,0 sample_s16_le.wav Playing WAVE 'sample_s16_le.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Now, from the headset we can hear music is playing out.
Class 2.0
Ez-Kit target board
root@adsp-sc589-ezkit:~# ls /dev/snd/ controlC0 pcmC0D0p pcmC0D1c timer root@adsp-sc589-ezkit:~# modprobe g_audio c_srate=48000 g_audio gadget: Linux USB Audio Gadget, version: Feb 2, 2012 g_audio gadget: g_audio ready g_audio gadget: high-speed config #1: Linux USB Audio Gadget
New Sound Card UAC2Gadget(card 1) is generated both for playback and capture on ezkit board:
root@adsp-sc589-ezkit:~# arecord -l **** List of CAPTURE Hardware Devices **** card 0: sc5xxasoccard [sc5xx-asoc-card], device 1: ADAU1979 adau1977-hifi-1 [] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: UAC2Gadget [UAC2_Gadget], device 0: UAC2 PCM [UAC2 PCM] Subdevices: 1/1 Subdevice #0: subdevice #0 root@adsp-sc589-ezkit:~# aplay -l **** List of PLAYBACK Hardware Devices **** card 0: sc5xxasoccard [sc5xx-asoc-card], device 0: ADAU1962 adau1962.0-0004-0 [] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: UAC2Gadget [UAC2_Gadget], device 0: UAC2 PCM [UAC2 PCM] Subdevices: 1/1 Subdevice #0: subdevice #0
Record audio data from the new generated UAC2 sound card (arecord card 1, device 0) and play the record data via normal playback device (aplay card 0, device 1)
root@adsp-sc589-ezkit:~# arecord -f dat -t wav -D hw:1,0 -c 2 -r 48000 -f S16_LE |aplay -D hw:0,0 Recording WAVE 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo Playing WAVE 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Play audio over USB on Host
On Iphone
Just play music on your Iphone, you will hear the sound output from ezkit board.
On the Linux-Host PC
With following command you should be able to see the USB Gadget Audio device is there on your HOST:
test@madara:~$ lsusb Bus 002 Device 033: ID 1d6b:0101 Linux Foundation Audio Gadget
Then we list the available sound card on host PC, to decide which sound card is associated with EZKIT board
test@madara:~$ cat /proc/asound/cards 0 [PCH ]: HDA-Intel - HDA Intel PCH HDA Intel PCH at 0xf7d00000 irq 28 1 [Gadget ]: USB-Audio - Linux USB Audio Gadget Linux 4.19.0-yocto-standard with musb-hdrc Linux USB Audio Gadget at usb-0000:0
test@madara:~$ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: Gadget [Linux USB Audio Gadget], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 test@madara:~$ arecord -l **** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 2: CX20641 Alt Analog [CX20641 Alt Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: Gadget [Linux USB Audio Gadget], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0
USB Auido Gadget is the sound card 1 (aplay card 1, device 0) and Play audio file
test@madara:~$ aplay -D hw:1,0 sample_s16_le.wav Playing WAVE 'sample_s16_le.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Now, from the headset we can hear music is playing out.
Go TO USB Interface
resources/tools-software/linuxdsp/docs/linux-kernel-and-drivers/usb/device_mode/gdaget_audio.txt · Last modified: 15 Jul 2020 08:17 by sullivan liu