NAME¶

struct_usb_configuration - represents one gadget configuration

SYNOPSIS¶

struct usb_configuration {


  const char * label;


  struct usb_gadget_strings ** strings;


  const struct usb_descriptor_header ** descriptors;


  int (* bind) (struct usb_configuration *);


  void (* unbind) (struct usb_configuration *);


  int (* setup) (struct usb_configuration *,const struct usb_ctrlrequest *);


  u8 bConfigurationValue;


  u8 iConfiguration;


  u8 bmAttributes;


  u8 bMaxPower;


  struct usb_composite_dev * cdev;
};  

MEMBERS¶

label

strings

descriptors

bind

unbind

setup

bConfigurationValue

iConfiguration

bmAttributes

bMaxPower

cdev

DESCRIPTION¶

Configurations are building blocks for gadget drivers structured around function drivers. Simple USB gadgets require only one function and one configuration, and handle dual-speed hardware by always providing the same functionality. Slightly more complex gadgets may have more than one single-function configuration at a given speed; or have configurations that only work at one speed.

Composite devices are, by definition, ones with configurations which include more than one function.

The lifecycle of a usb_configuration includes allocation, initialization of the fields described above, and calling usb_add_config() to set up internal data and bind it to a specific device. The configuration´s bind() method is then used to initialize all the functions and then call usb_add_function() for them.

Those functions would normally be independant of each other, but that´s not mandatory. CDC WMC devices are an example where functions often depend on other functions, with some functions subsidiary to others. Such interdependency may be managed in any way, so long as all of the descriptors complete by the time the composite driver returns from its bind routine.

AUTHOR¶

David Brownell <dbrownell@users.sourceforge.net>

COPYRIGHT¶