FAQ_MA35D1_Change Display Clock

[ytliu6]

If you need to change the display panel or change the display clock
First, you need to modify MA35D1 device tree description.
There are two methods you can use

You can modify ma35d1.dtsi or modify dts to override the description

The display clock use clk_VPLL, so you need to modify it to match your display
For example, the display panel provided by Nuvoton is compatible with 51 MHz, and the display driver will let 102 MHz is divided by 2.
If you need display clock 100 MHz, the VPLL should be 200MHz

ma35d1.dtsi

Code: Select all

clk: clock-controller@40460200 {
        ...
        assigned-clocks = <&clk CAPLL>,
                <&clk DDRPLL>, <&clk APLL>,
                <&clk EPLL>, <&clk VPLL>;
        assigned-clock-rates =<1000000000>,
                <266000000>, <200000000>,
                <500000000>, <102000000>;
        ...
    };

The following description will override ma35d1.dtsi, so you don’t need to modify dtsi

ma35d1-som-256m.dts

Code: Select all

&clk{
    assigned-clock-rates =<1000000000>,
                <266000000>, <282240000>,
                <500000000>, <102000000>;
};