Documentation/usb/gadget_uvc.rst

6 --------
8 connection. It is intended to run on a Linux system that has USB device-side
12 the output capability.
24 -----------------------------
29 ---------------------------------------
35 see Documentation/ABI/testing/configfs-usb-gadget-uvc
39 This section assumes that you have mounted configfs at `/sys/kernel/config` and
40 created a gadget as `/sys/kernel/config/usb_gadget/g1`.
47 .. code-block:: bash
50 	CONFIGFS="/sys/kernel/config"
54 	mkdir -p $FUNCTION
99 .. code-block:: bash
112 		mkdir -p $wdir
129 Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst.
142 .. code-block:: bash
155 	# Create a symlink to the Color Matching Descriptor from the format's config item
156 	ln -s $FUNCTION/streaming/color_matching/yuyv $FUNCTION/streaming/uncompressed/yuyv
173 config items representing those other descriptors, in this manner:
175 .. code-block:: bash
182 	ln -s ../../uncompressed/yuyv
183 	ln -s ../../mjpeg/mjpeg
189 	ln -s ../../header/h
191 	ln -s ../../header/h
193 	ln -s ../../header/h
196 	ln -s header/h class/fs
197 	ln -s header/h class/ss
207 XU can be inserted into the UVC unit chain or left free-hanging.
212 .. code-block:: bash
221 	# Set this XU as the source of the default output terminal. This inserts
224 	cat bUnitID > ../../terminal/output/default/baSourceID
231 	# Set the GUID; this is a vendor-specific code identifying the XU.
232 	echo -e -n "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10" > guidExtensionCode
236 The bmControls attribute and the baSourceID attribute are multi-value attributes.
241 .. code-block:: bash
248 The multi-value nature of the baSourceID attribute belies the fact that XUs can
249 be multiple-input, though note that this currently has no significant effect.
287 .. code-block:: bash
297 If you do not set these fields then by default the Auto-Exposure Mode control
304 read-only here.
306 Custom Strings Support
314 .. code-block:: bash
316 	# Create a string descriptor in us-EN and link to it from the function
322 	mkdir -p $GADGET/strings/0x409/iad_desc
323 	echo -n "Interface Associaton Descriptor" > $GADGET/strings/0x409/iad_desc/s
324 	ln -s $GADGET/strings/0x409/iad_desc $FUNCTION/iad_desc
330 	mkdir -p $GADGET/strings/0x409/xu.0
331 	echo -n "A Very Useful Extension Unit" > $GADGET/strings/0x409/xu.0/s
332 	ln -s $GADGET/strings/0x409/xu.0 $FUNCTION/control/extensions/xu.0
344 .. code-block:: bash
354 .. code-block:: bash
356 	# streaming_interval sets bInterval. Values range from 1..255
375 -------------------------
380 document, but a reference application can be found at https://gitlab.freedesktop.org/camera/uvc-gad…