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Diffstat (limited to 'Documentation/usb')
| -rw-r--r-- | Documentation/usb/gadget-testing.txt | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt index 5ac9dc7..076ac7b 100644 --- a/Documentation/usb/gadget-testing.txt +++ b/Documentation/usb/gadget-testing.txt @@ -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 |