usb_gadget_config_bu(9)
NAME
usb_gadget_config_buf - builts a complete configuration descriptor
SYNOPSIS
int usb_gadget_config_buf(const struct usb_config_descriptor * config,
void * buf, unsigned length,
const struct usb_descriptor_header ** desc);
ARGUMENTS
- config
- Header for the descriptor, including characteristics such as power requirements and number of interfaces.
- buf
- Buffer for the resulting configuration descriptor.
- length
- Length of buffer. If this is not big enough to hold the entire
configuration descriptor, an error code will be returned. - desc
- Null-terminated vector of pointers to the descriptors (interface,
endpoint, etc) defining all functions in this device configuration.
DESCRIPTION
This copies descriptors into the response buffer, building a descriptor
for that configuration. It returns the buffer length or a negative
status code. The config.wTotalLength field is set to match the length
of the result, but other descriptor fields (including power usage and
interface count) must be set by the caller.
Gadget drivers could use this when constructing a config descriptor in
response to USB_REQ_GET_DESCRIPTOR. They will need to patch the
resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.
AUTHOR
- David Brownell <dbrownell@users.sourceforge.net>
- Author.