What:		/config/usb-gadget
Date:		Jun 2013
KernelVersion:	3.11
Description:
		This group contains sub-groups corresponding to created
		USB gadgets.

What:		/config/usb-gadget/gadget
Date:		Jun 2013
KernelVersion:	3.11
Description:

		The attributes of a gadget:

		================  ============================================
		UDC		  bind a gadget to UDC/unbind a gadget;
				  write UDC's name found in /sys/class/udc/*
				  to bind a gadget, empty string "" to unbind.

		max_speed	  maximum speed the driver supports. Valid
				  names are super-speed-plus, super-speed,
				  high-speed, full-speed, and low-speed.

		bDeviceClass	  USB device class code
		bDeviceSubClass	  USB device subclass code
		bDeviceProtocol	  USB device protocol code
		bMaxPacketSize0	  maximum endpoint 0 packet size
		bcdDevice	  bcd device release number
		bcdUSB		  bcd USB specification version number
		idProduct	  product ID
		idVendor	  vendor ID
		================  ============================================

What:		/config/usb-gadget/gadget/configs
Date:		Jun 2013
KernelVersion:	3.11
Description:
		This group contains a USB gadget's configurations

What:		/config/usb-gadget/gadget/configs/config
Date:		Jun 2013
KernelVersion:	3.11
Description:
		The attributes of a configuration:

		================  ======================================
		bmAttributes	  configuration characteristics
		MaxPower	  maximum power consumption from the bus
		================  ======================================

What:		/config/usb-gadget/gadget/configs/config/strings
Date:		Jun 2013
KernelVersion:	3.11
Description:
		This group contains subdirectories for language-specific
		strings for this configuration.

What:		/config/usb-gadget/gadget/configs/config/strings/language
Date:		Jun 2013
KernelVersion:	3.11
Description:
		The attributes:

		================  =========================
		configuration	  configuration description
		================  =========================


What:		/config/usb-gadget/gadget/functions
Date:		Jun 2013
KernelVersion:	3.11
Description:
		This group contains functions available to this USB gadget.

What:		/config/usb-gadget/gadget/functions/<func>.<inst>/interface.<n>
Date:		May 2014
KernelVersion:	3.16
Description:
		This group contains "Feature Descriptors" specific for one
		gadget's USB interface or one interface group described
		by an IAD.

		The attributes:

		=================	=====================================
		compatible_id		8-byte string for "Compatible ID"
		sub_compatible_id	8-byte string for "Sub Compatible ID"
		=================	=====================================

What:		/config/usb-gadget/gadget/functions/<func>.<inst>/interface.<n>/<property>
Date:		May 2014
KernelVersion:	3.16
Description:
		This group contains "Extended Property Descriptors" specific for one
		gadget's USB interface or one interface group described
		by an IAD.

		The attributes:

		=====		===============================================
		type		value 1..7 for interpreting the data

				- 1: unicode string
				- 2: unicode string with environment variable
				- 3: binary
				- 4: little-endian 32-bit
				- 5: big-endian 32-bit
				- 6: unicode string with a symbolic link
				- 7: multiple unicode strings
		data		blob of data to be interpreted depending on
				type
		=====		===============================================

What:		/config/usb-gadget/gadget/strings
Date:		Jun 2013
KernelVersion:	3.11
Description:
		This group contains subdirectories for language-specific
		strings for this gadget.

What:		/config/usb-gadget/gadget/strings/language
Date:		Jun 2013
KernelVersion:	3.11
Description:
		The attributes:

		============	=================================
		serialnumber	gadget's serial number (string)
		product		gadget's product description
		manufacturer	gadget's manufacturer description
		============	=================================

What:		/config/usb-gadget/gadget/os_desc
Date:		May 2014
KernelVersion:	3.16
Description:
		This group contains "OS String" extension handling attributes.

		=============	===============================================
		use		flag turning "OS Desctiptors" support on/off
		b_vendor_code	one-byte value used for custom per-device and
				per-interface requests
		qw_sign		an identifier to be reported as "OS String"
				proper
		=============	===============================================
