The NuttX USB host infrastructure includes a <i>registry</i>.
During its initialization, each USB host class driver must call the interface, <code>usbhost_registerclass()</code>
in order add its interface to the register.
in order add its interface to the registery.
Later, when a USB device is connected, the USB host controller will look up the USB host class driver that is needed to support the connected device in this registry.