Hi all,
In \FmpDevicePkg\Library\FmpDeviceLibNull\FmpDeviceLib.c
There are comments for RegisterFmpInstaller:

/**
  Used to pass the FMP install function to this lib.  This allows the library to
  have control of the handle that the FMP instance is installed on.  This allows
  the library to use DriverBinding protocol model to locate its device(s) in the
  system.

  @param[in] Func  Function pointer to FMP install function.

  @retval EFI_SUCCESS       Library has saved function pointer and will call
                            function pointer on each DriverBinding Start.
  @retval EFI_UNSUPPORTED   Library doesn't use driver binding and only supports
                            a single instance.
  @retval other error       Error occurred.  Don't install FMP

**/
EFI_STATUS
EFIAPI
RegisterFmpInstaller (
  IN FMP_DEVICE_LIB_REGISTER_FMP_INSTALLER Func
  )
{
  //
  // This is a system firmware update that does not use Driver Binding Protocol
  //
  return EFI_UNSUPPORTED;
}

However, since the ‘RegisterFmpInstaller’ of the example directly returns EFI_UNSUPPORTED, it does not demonstrate how to handle the DriverBinding protocol. There are similar instructions in the edk2-platforms example, but it also does not demonstrate how to locate the DriverBinding protocol. The full path of edk2-platforms example is :
edk2-platforms\Platform\Intel\Vlv2TbltDevicePkg\Feature\Capsule\Library\FmpDeviceLib\FmpDeviceLib.c

I would like to operate USBIO in FmpDxe, how to do Binding protocol in FmpDxe, is there any sample code?
Any suggestion is greatly appreciated!
Many thanks!