Hi Andy, On Mon, Jul 6, 2020 at 1:30 AM Andy Duan <fugang.duan@xxxxxxx> wrote: > > The clock depends on board design, HW refer guide can describe the clk > usage in detail and customer select one clk path as their board design. > Yes, I agree. But how does a board designer practically describe this in the devicetree? Example: mac_gtx -> clk_pad (the default) Imagine I have a fixed oscillator on the board: phy_ref_clk: oscillator { compatible = "fixed-clock"; #clock-cells = <0>; clock-frequency = <50000000>; }; How can I now make <&phy_ref_clk> the parent of <&clks CLK_PAD> ?