Hi Paul,
Le mar., oct. 5 2021 at 23:44:12 +0200, Paul Boddie
<paul@xxxxxxxxxxxxx> a écrit :
On Tuesday, 5 October 2021 22:50:12 CEST Paul Cercueil wrote:
Hi Nikolaus & Paul,
Le mar., oct. 5 2021 at 14:29:17 +0200, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> a écrit :
>
> diff --git a/arch/mips/boot/dts/ingenic/jz4780.dtsi
> b/arch/mips/boot/dts/ingenic/jz4780.dtsi
> index 9e34f433b9b5..c3c18a59c377 100644
> --- a/arch/mips/boot/dts/ingenic/jz4780.dtsi
> +++ b/arch/mips/boot/dts/ingenic/jz4780.dtsi
> @@ -424,6 +424,51 @@ i2c4: i2c@10054000 {
>
> status = "disabled";
>
> };
>
> + hdmi: hdmi@10180000 {
> + compatible = "ingenic,jz4780-dw-hdmi";
> + reg = <0x10180000 0x8000>;
> + reg-io-width = <4>;
> +
> + clocks = <&cgu JZ4780_CLK_AHB0>, <&cgu JZ4780_CLK_HDMI>;
> + clock-names = "iahb", "isfr";
> +
> + assigned-clocks = <&cgu JZ4780_CLK_HDMI>;
> + assigned-clock-rates = <27000000>;
Any reason why this is set to 27 MHz? Is it even required? Because
with
the current ci20.dts, it won't be clocked at anything but 48 MHz.
EXCLK will be 48MHz, but the aim is to set the HDMI peripheral clock
to 27MHz,
which is supposedly required. I vaguely recall a conversation about
whether we
were doing this right, but I don't recall any conclusion.
But right now your HDMI clock is 48 MHz and HDMI works.
> +
> + interrupt-parent = <&intc>;
> + interrupts = <3>;
> +
> + /* ddc-i2c-bus = <&i2c4>; */
> +
> + status = "disabled";
> + };
> +
> + lcdc0: lcdc0@13050000 {
> + compatible = "ingenic,jz4780-lcd";
> + reg = <0x13050000 0x1800>;
> +
> + clocks = <&cgu JZ4780_CLK_TVE>, <&cgu JZ4780_CLK_LCD0PIXCLK>;
> + clock-names = "lcd", "lcd_pclk";
> +
> + interrupt-parent = <&intc>;
> + interrupts = <31>;
> +
> + status = "disabled";
I think you can keep lcdc0 enabled by default (not lcdc1 though),
since
it is highly likely that you'd want that.
As far as I know, the clock gating for the LCD controllers acts like
a series
circuit, meaning that they both need to be enabled. Some testing
seemed to
confirm this. Indeed, I seem to remember only enabling one clock and
not
getting any output until I figured this weird arrangement out.
I'm not talking about clocks though, but about LCDC0 and LCDC1.
Cheers,
-Paul
