DRM has a format for 8-bit greyscale data, DRM_FORMAT_R8. Despite the 'R' name, which comes from GL/Vulkan to mean single-channel data, the format maps to greyscale for display. We can thus map it to V4L2_PIX_FMT_GREY. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>