usb gadget: function activation/deactivation

Add a new mechanism to the composite gadget framework, letting
functions deactivate (and reactivate) themselves. Think of it
as a refcou

usb gadget: function activation/deactivation

Add a new mechanism to the composite gadget framework, letting
functions deactivate (and reactivate) themselves. Think of it
as a refcounted wrapper for the software pullup control.

A key example of why to use this mechanism involves functions that
require a userspace daemon. Those functions shuld use this new
mechanism to prevent the gadget from enumerating until those daemons
are activated. Without this mechanism, hosts would see devices that
malfunction until the relevant daemons start.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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usb gadget: minor USBCV fix for composite framework

Fill in a reserved/unused device qualifier field to ensure that
the USBCV tests will always pass.

Signed-off-by: David Browne

usb gadget: minor USBCV fix for composite framework

Fill in a reserved/unused device qualifier field to ensure that
the USBCV tests will always pass.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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usb gadget: composite gadget core

Add <linux/usb/composite.h> interfaces for composite gadget drivers, and
basic implementation support behind it:

- struct usb_function ... gr

usb gadget: composite gadget core

Add <linux/usb/composite.h> interfaces for composite gadget drivers, and
basic implementation support behind it:

- struct usb_function ... groups one or more interfaces into a function
managed as one unit within a configuration, to which it's added by
usb_add_function().

- struct usb_configuration ... groups one or more such functions into
a configuration managed as one unit by a driver, to which it's added
by usb_add_config(). These operate at either high or full/low speeds
and at a given bMaxPower.

- struct usb_composite_driver ... groups one or more such configurations
into a gadget driver, which may be registered or unregistered.

- struct usb_composite_dev ... a usb_composite_driver manages this; it
wraps the usb_gadget exposed by the controller driver.

This also includes some basic kerneldoc.

How to use it (the short version): provide a usb_composite_driver with a
bind() that calls usb_add_config() for each of the needed configurations.
The configurations in turn have bind() calls, which will usb_add_function()
for each function required. Each function's bind() allocates resources
needed to perform its tasks, like endpoints; sometimes configurations will
allocate resources too.

Separate patches will convert most gadget drivers to this infrastructure.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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