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/
ln -s header/h class/fs
ln -s header/h class/ss
mkdir -p functions/uvc.usb0/streaming/uncompressed/u/360p
cat < 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
- PRINTER function
====================
The function is provided by usb_f_printer.ko module.
Function-specific configfs interface
The function name to use when creating the function directory is "printer".
The printer function provides these attributes in its function directory:
pnp_string - Data to be passed to the host in pnp string
q_len - Number of requests per endpoint
Testing the PRINTER function
The most basic testing:
device: run the gadget