struct_usb_gadget(9) [suse man page]

STRUCT 
USB_GADGET(9)					      Kernel Mode Gadget API					      STRUCT USB_GADGET(9)

NAME

       struct_usb_gadget - represents a usb slave device

SYNOPSIS

       struct usb_gadget {
	 const struct usb_gadget_ops * ops;
	 struct usb_ep * ep0;
	 struct list_head ep_list;
	 enum usb_device_speed speed;
	 unsigned is_dualspeed:1;
	 unsigned is_otg:1;
	 unsigned is_a_peripheral:1;
	 unsigned b_hnp_enable:1;
	 unsigned a_hnp_support:1;
	 unsigned a_alt_hnp_support:1;
	 const char * name;
	 struct device dev;
       };

MEMBERS

       ops
	   Function pointers used to access hardware-specific operations.

       ep0
	   Endpoint zero, used when reading or writing responses to driver setup requests

       ep_list
	   List of other endpoints supported by the device.

       speed
	   Speed of current connection to USB host.

       is_dualspeed
	   True if the controller supports both high and full speed operation. If it does, the gadget driver must also support both.

       is_otg
	   True if the USB device port uses a Mini-AB jack, so that the gadget driver must provide a USB OTG descriptor.

       is_a_peripheral
	   False unless is_otg, the "A" end of a USB cable is in the Mini-AB jack, and HNP has been used to switch roles so that the "A" device
	   currently acts as A-Peripheral, not A-Host.

       b_hnp_enable
	   OTG device feature flag, indicating that the A-Host enabled HNP support.

       a_hnp_support
	   OTG device feature flag, indicating that the A-Host supports HNP at this port.

       a_alt_hnp_support
	   OTG device feature flag, indicating that the A-Host only supports HNP on a different root port.

       name
	   Identifies the controller hardware type. Used in diagnostics and sometimes configuration.

       dev
	   Driver model state for this abstract device.

DESCRIPTION

       Gadgets have a mostly-portable "gadget driver" implementing device functions, handling all usb configurations and interfaces. Gadget
       drivers talk to hardware-specific code indirectly, through ops vectors. That insulates the gadget driver from hardware details, and
       packages the hardware endpoints through generic i/o queues. The "usb_gadget" and "usb_ep" interfaces provide that insulation from the
       hardware.

       Except for the driver data, all fields in this structure are read-only to the gadget driver. That driver data is part of the "driver model"
       infrastructure in 2.6 (and later) kernels, and for earlier systems is grouped in a similar structure that's not known to the rest of the
       kernel.

       Values of the three OTG device feature flags are updated before the setup call corresponding to USB_REQ_SET_CONFIGURATION, and before
       driver suspend calls. They are valid only when is_otg, and when the device is acting as a B-Peripheral (so is_a_peripheral is false).

AUTHOR

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

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010						      STRUCT USB_GADGET(9)

STRUCT 
USB_CONFIGURA(9) 				      Kernel Mode Gadget API					   STRUCT USB_CONFIGURA(9)

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;
	 void (* unbind) (struct usb_configuration *);
	 int (* setup) (struct usb_configuration *,const struct usb_ctrlrequest *);
	 u8 bConfigurationValue;
	 u8 iConfiguration;
	 u8 bmAttributes;
	 u16 MaxPower;
	 struct usb_composite_dev * cdev;
       };

MEMBERS

       label
	   For diagnostics, describes the configuration.

       strings
	   Tables of strings, keyed by identifiers assigned during bind() and by language IDs provided in control requests.

       descriptors
	   Table of descriptors preceding all function descriptors. Examples include OTG and vendor-specific descriptors.

       unbind
	   Reverses bind; called as a side effect of unregistering the driver which added this configuration.

       setup
	   Used to delegate control requests that aren't handled by standard device infrastructure or directed at a specific interface.

       bConfigurationValue
	   Copied into configuration descriptor.

       iConfiguration
	   Copied into configuration descriptor.

       bmAttributes
	   Copied into configuration descriptor.

       MaxPower
	   Power consumtion in mA. Used to compute bMaxPower in the configuration descriptor after considering the bus speed.

       cdev
	   assigned by usb_add_config() before calling bind(); this is the device associated with this configuration.

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 independent 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>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   STRUCT USB_CONFIGURA(9)