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Diffstat (limited to 'Documentation/usb/gadget-testing.txt')
| -rw-r--r-- | Documentation/usb/gadget-testing.txt | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt index ce51d6e4e7d0..fbc397d17e98 100644 --- a/Documentation/usb/gadget-testing.txt +++ b/Documentation/usb/gadget-testing.txt @@ -20,6 +20,7 @@ provided by gadgets. 17. UAC2 function 18. UVC function 19. PRINTER function +20. UAC1 function (new API) 1. ACM function @@ -773,3 +774,46 @@ host: More advanced testing can be done with the prn_example described in Documentation/usb/gadget-printer.txt. + + +20. UAC1 function (virtual ALSA card, using u_audio API) +================= + +The function is provided by usb_f_uac1.ko module. +It will create a virtual ALSA card and the audio streams are simply +sinked to and sourced from it. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "uac1". +The uac1 function provides these attributes in its function directory: + + c_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) + req_number - the number of pre-allocated request for both capture + and playback + +The attributes have sane default values. + +Testing the UAC1 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=UAC1Gadget,DEV=0 | \ +aplay -D default:CARD=OdroidU3 |