linux/usb/composite.h

2  * composite.h -- framework for usb gadgets which are composite devices
4  * Copyright (C) 2006-2008 David Brownell
6  * SPDX-License-Identifier:	GPL-2.0+
14  * making it easier to build (a) Composite devices, supporting multiple
15  * functions within any single configuration, and (b) Multi-configuration
20  * link and mass storage functions is a composite device.  Those functions
21  * might alternatively be packaged in individual configurations, but in
22  * the composite model the host can use both functions at the same time.
42  * struct usb_function - describes one function of a configuration
45  *	and by language IDs provided in control requests
59  *	in interface or class descriptors; endpoints; I/O buffers; and so on.
70  * @setup: Used for interface-specific control requests.
74  * A single USB function uses one or more interfaces, and should in most
82  * for both high and full speed operation.  Except in rare cases that don't
87  * can only be activated once.  If the function needs to be exposed in more
92  * a driver-specific instance structure to allows multiple activations.  An
143  * ep_choose - select descriptor endpoint at current device speed
152 	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)  in ep_choose()
160  * struct usb_configuration - represents one gadget configuration
163  *	and by language IDs provided in control requests.
165  *	Examples include OTG and vendor-specific descriptors.
181  * configuration, and handle dual-speed hardware by always providing the same
183  * single-function configuration at a given speed; or have configurations
186  * Composite devices are, by definition, ones with configurations which
198  * Such interdependency may be managed in any way, so long as all of the
199  * descriptors complete by the time the composite driver returns from
218 	/* fields in the config descriptor */
241  * struct usb_composite_driver - groups configurations into a gadget
246  *	and language IDs provided in control requests
260  * on bus powered operation should report this in their @bind() method.
262  * Before returning from @bind, various fields in the template descriptor
267  * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
295  * struct usb_composite_device - represents one composite usb gadget
296  * @gadget: read-only, abstracts the gadget's usb peripheral controller
297  * @req: used for control responses; buffer is pre-allocated
298  * @bufsiz: size of buffer pre-allocated in @req
313  *     "is it wired", plus (presumably in a wrapper structure)
316  *     wireless-specific parameters like maxburst and maxsequence;
322  * (g) composite device setup that can create one or more wireless