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Commit 9c4f538b authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
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Documentation: usb: UVC function testing 



Summary of how to test UVC function of USB gadget.

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 020c6f93

Documentation/usb/gadget-testing.txt

+73 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ provided by gadgets. 
15. SOURCESINK function

16. UAC1 function

17. UAC2 function

18. UVC function





1. ACM function
@@ -653,3 +654,75 @@ e.g.: 


$ arecord -f dat -t wav -D hw:CARD=UAC2Gadget,DEV=0 | \

aplay -D default:CARD=OdroidU3



18. UVC function

================



The function is provided by usb_f_uvc.ko module.



Function-specific configfs interface

------------------------------------



The function name to use when creating the function directory is "uvc".

The uvc function provides these attributes in its function directory:



	streaming_interval - interval for polling endpoint for data transfers

	streaming_maxburst - bMaxBurst for super speed companion descriptor

	streaming_maxpacket - maximum packet size this endpoint is capable of

			      sending or receiving when this configuration is

			      selected



There are also "control" and "streaming" subdirectories, each of which contain

a number of their subdirectories. There are some sane defaults provided, but

the user must provide the following:



	control header - create in control/header, link from control/class/fs

			and/or control/class/ss

	streaming header - create in streaming/header, link from

			streaming/class/fs and/or streaming/class/hs and/or

			streaming/class/ss

	format description - create in streaming/mjpeg and/or

			streaming/uncompressed

	frame description - create in streaming/mjpeg/<format> and/or in

			streaming/uncompressed/<format>



Each frame description contains frame interval specification, and each

such specification consists of a number of lines with an inverval value

in each line. The rules stated above are best illustrated with an example:



# mkdir functions/uvc.usb0/control/header/h

# cd functions/uvc.usb0/control/header/h

# ln -s header/h class/fs

# ln -s header/h class/ss

# mkdir -p functions/uvc.usb0/streaming/uncompressed/u/360p

# cat <<EOF > functions/uvc.usb0/streaming/uncompressed/u/360p/dwFrameInterval

666666

1000000

5000000

EOF

# cd $GADGET_CONFIGFS_ROOT

# mkdir functions/uvc.usb0/streaming/header/h

# cd functions/uvc.usb0/streaming/header/h

# ln -s ../../uncompressed/u

# cd ../../class/fs

# ln -s ../../header/h

# cd ../../class/hs

# ln -s ../../header/h

# cd ../../class/ss

# ln -s ../../header/h





Testing the UVC function

------------------------



device: run the gadget, modprobe vivid



# uvc-gadget -u /dev/video<uvc video node #> -v /dev/video<vivid video node #>



where uvc-gadget is this program:

http://git.ideasonboard.org/uvc-gadget.git



with these patches:

http://www.spinics.net/lists/linux-usb/msg99220.html



host: luvcview -f yuv