23 Mar, 2017

1 commit

  • Certain boards come in different variations by way of utilizing daughter
    boards, for example. These boards might contain additional chips, which
    are added to the main board's busses, e.g. I2C.

    The device tree support for such boards would either, quite naturally,
    employ the overlay mechanism to add such chips to the tree, or would use
    one large default device tree, and delete the devices that are actually
    not present.

    Regardless of approach, even on the U-Boot level, a modification of the
    device tree is a prerequisite to have such modular families of boards
    supported properly.

    Therefore, we add an option to make the U-Boot device tree (the actual
    copy later used by the driver model) writeable, and add a callback
    method that allows boards to modify the device tree at an early stage,
    at which, hopefully, also the application of device tree overlays will
    be possible.

    Signed-off-by: Mario Six
    Reviewed-by: Simon Glass
    Signed-off-by: Stefan Roese

    mario.six@gdsys.cc