Re: [02/11] video: ARM CLCD: support DT signal inversion flags

On Wed, Feb 17, 2016 at 7:10 PM, Ray Jui [off-list ref] wrote:

A somewhat related question, how do you see the CLKSEL bit in the TIM2
register will be supported in the future? There are some cases where the
CLKSEL bit needs to be set, and therefore the "CLCDCLK" instead of "HCLK"
reference clock source is selected.

I think it's very simple:

The DT node usually looks like so:

display@10120000 {
        compatible = "arm,pl110", "arm,primecell";
(...)
        clocks = <&oscclk4>, <&pclk>;
        clock-names = "clcd", "apb_pclk";

Just add a custom attribute pointing to the
reference clock in this array:

clcd-reference-clock = <0>;

If this is set to <1> "apb_pclk" (i.e. HCLK) is
the reference, and that bit in TIM2 gets set.

Do you have a system that needs this?

Yours,
Linus Walleij