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Documentation: usb: UAC2 function testing 

Summary of how to test UAC2 function of USB gadget.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
hifive-unleashed-5.1
Andrzej Pietrasiewicz 2014-12-16 14:56:41 +01:00 committed by Felipe Balbi
parent dae0358694
commit 020c6f9348
1 changed files with 39 additions and 0 deletions
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39
Documentation/usb/gadget-testing.txt
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@ -17,6 +17,7 @@ provided by gadgets.
14. SERIAL function
15. SOURCESINK function
16. UAC1 function
17. UAC2 function
1. ACM function
@ -614,3 +615,41 @@ Testing the UAC1 function
device: run the gadget
host: aplay -l # should list our USB Audio Gadget
17. UAC2 function
=================
The function is provided by usb_f_uac2.ko module.
Function-specific configfs interface
------------------------------------
The function name to use when creating the function directory is "uac2".
The uac2 function provides these attributes in its function directory:
chmask - capture channel mask
c_srate - capture sampling rate
c_ssize - capture sample size (bytes)
p_chmask - playback channel mask
p_srate - playback sampling rate
p_ssize - playback sample size (bytes)
The attributes have sane default values.
Testing the UAC2 function
-------------------------
device: run the gadget
host: aplay -l # should list our USB Audio Gadget
This function does not require real hardware support, it just
sends a stream of audio data to/from the host. In order to
actually hear something at the device side, a command similar
to this must be used at the device side:
$ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 &
e.g.:
$ arecord -f dat -t wav -D hw:CARD=UAC2Gadget,DEV=0 | \
aplay -D default:CARD=OdroidU3