| usb_get_descriptor(9) - phpMan
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 4.8. January 2017 USB_GET_DESCRIPTOR(9)
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