centos man page for usb_get_descriptor

USB_GET_DESCRIPTOR(9)						   USB Core APIs					     USB_GET_DESCRIPTOR(9)

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 "buf"?

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.

RETURN
       The number of bytes received on success, or else the status code returned by the underlying usb_control_msg call.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						     USB_GET_DESCRIPTOR(9)