USB_GET_DESCRIPTOR

Section: USB Core APIs (9)
Updated: February 2011
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NAME

usb_get_descriptor - issues a generic GET_DESCRIPTOR request

SYNOPSIS

int usb_get_descriptor(struct usb_device * dev, unsigned char type, unsigned char index, void * buf, int size);

ARGUMENTS

dev

: the device whose descriptor is being retrieved

type

: the descriptor type (USB_DT_*)

index

: the number of the descriptor

buf

: where to put the descriptor

size

: how big is lqbufrq?

CONTEXT

!in_interrupt ()

DESCRIPTION

Gets a USB descriptor. Convenience functions exist to simplify getting some types of descriptors. Use usb_get_string or usb_string for USB_DT_STRING. Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG) are part of the device structure. In addition to a number of USB-standard descriptors, some devices also use class-specific or vendor-specific descriptors.

This call is synchronous, and may not be used in an interrupt context.