This is the device tree overlay(s) and its make. The purpose of the overlay is to define the system for the mts-io driver and/or mtac drivers. The correct overlay for the system is loaded at runtime before loading the mts-io driver. A method for doing this is the device tree configfs driver. See this for the format of an overlay: https://www.kernel.org/doc/Documentation/devicetree/overlay-notes.txt Note that as of 10 May 2019, no overlays have been released. The biggest flaw in overlays, is the inablitiy to use the phandle described in an alias in the boot time device tree in an overlay, so it appears to be impossible to reference nodes in the main device tree in any shorthand method. For instance, it is common to reference a "pio" in device tree to use a PIO with GPIO. For example, it does not appear to be possible to use &pioC in the overlay without redefining it.