Re: [PATCH] arm64: dts: imx8mq: Add clock parents for mipi dphy

[Shawn Guo]

On Fri, Dec 18, 2020 at 06:50:05PM +0100, Guido Günther wrote:
> This makes sure the clock tree setup for the dphy is not dependent on
> other components.
> 
> Without this change bringing up the display can fail like
> 
>   kernel: phy phy-30a00300.dphy.2: Invalid CM/CN/CO values: 165/217/1
>   kernel: phy phy-30a00300.dphy.2: for hs_clk/ref_clk=451656000/593999998 ~ 165/217
> 
> if LCDIF doesn't set up that part of the clock tree first. This was
> noticed when testing the Librem 5 devkit with defconfig. It doesn't
> happen when modules are built in.
> 
> Signed-off-by: Guido Günther <agx@xxxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/freescale/imx8mq.dtsi | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> index a841a023e8e0..ca0847e8f13c 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> @@ -1016,9 +1016,14 @@ dphy: dphy@30a00300 {
>  				reg = <0x30a00300 0x100>;
>  				clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
>  				clock-names = "phy_ref";
> -				assigned-clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
> -				assigned-clock-parents = <&clk IMX8MQ_VIDEO_PLL1_OUT>;
> -				assigned-clock-rates = <24000000>;
> +				assigned-clocks = <&clk IMX8MQ_VIDEO_PLL1_REF_SEL>,
> +						  <&clk IMX8MQ_VIDEO_PLL1_BYPASS>,
> +						  <&clk IMX8MQ_CLK_DSI_PHY_REF>,
> +						  <&clk IMX8MQ_VIDEO_PLL1>;

You do not seem to set parent or rate on IMX8MQ_VIDEO_PLL1.  Why do you
have it here?

Shawn

> +				assigned-clock-parents = <&clk IMX8MQ_CLK_25M>,
> +						  <&clk IMX8MQ_VIDEO_PLL1>,
> +						  <&clk IMX8MQ_VIDEO_PLL1_OUT>;
> +				assigned-clock-rates = <0>, <0>, <24000000>;
>  				#phy-cells = <0>;
>  				power-domains = <&pgc_mipi>;
>  				status = "disabled";
> -- 
> 2.29.2
>