usb_interface_id(9) [centos man page]

USB_INTERFACE_ID(9)					      Kernel Mode Gadget API					       USB_INTERFACE_ID(9)

NAME

       usb_interface_id - allocate an unused interface ID

SYNOPSIS

       int usb_interface_id(struct usb_configuration * config, struct usb_function * function);

ARGUMENTS

       config
	   configuration associated with the interface

       function
	   function handling the interface

CONTEXT

       single threaded during gadget setup

DESCRIPTION

       usb_interface_id is called from usb_function.bind callbacks to allocate new interface IDs. The function driver will then store that ID in
       interface, association, CDC union, and other descriptors. It will also handle any control requests targeted at that interface, particularly
       changing its altsetting via set_alt. There may also be class-specific or vendor-specific requests to handle.

       All interface identifier should be allocated using this routine, to ensure that for example different functions don't wrongly assign
       different meanings to the same identifier. Note that since interface identifiers are configuration-specific, functions used in more than
       one configuration (or more than once in a given configuration) need multiple versions of the relevant descriptors.

       Returns the interface ID which was allocated; or -ENODEV if no more interface IDs can be allocated.

AUTHOR

       David Brownell <dbrownell@users.sourceforge.net>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						       USB_INTERFACE_ID(9)

USB_GADGET_CONFIG_BU(9) 				      Kernel Mode Gadget API					   USB_GADGET_CONFIG_BU(9)

NAME

       usb_gadget_config_buf - builts a complete configuration descriptor

SYNOPSIS

       int usb_gadget_config_buf(const struct usb_config_descriptor * config, void * buf, unsigned length,
				 const struct usb_descriptor_header ** desc);

ARGUMENTS

       config
	   Header for the descriptor, including characteristics such as power requirements and number of interfaces.

       buf
	   Buffer for the resulting configuration descriptor.

       length
	   Length of buffer. If this is not big enough to hold the entire configuration descriptor, an error code will be returned.

       desc
	   Null-terminated vector of pointers to the descriptors (interface, endpoint, etc) defining all functions in this device configuration.

DESCRIPTION

       This copies descriptors into the response buffer, building a descriptor for that configuration. It returns the buffer length or a negative
       status code. The config.wTotalLength field is set to match the length of the result, but other descriptor fields (including power usage and
       interface count) must be set by the caller.

       Gadget drivers could use this when constructing a config descriptor in response to USB_REQ_GET_DESCRIPTOR. They will need to patch the
       resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.

AUTHOR

       David Brownell <dbrownell@users.sourceforge.net>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   USB_GADGET_CONFIG_BU(9)