Linux Certif

Toute la documentation sur la certification Linux LPI

struct_usb_gadget

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 lqArq end of a USB cable is in the Mini-AB jack, and HNP has been used to switch roles so that the lqArq 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 lqgadget driverrq 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 lqusb_gadgetrq and lqusb_eprq 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 lqdriver modelrq 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