Re: [PATCH net-next v4 05/10] arm64: dts: rockchip: rk3568: add XPCS and fixed-clock nodes

[Jakub Kicinski <kuba@kernel.org>]

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---
arm64: dts: rockchip: rk3568: add XPCS and fixed-clock nodes

This adds the RK3568 Synopsys DesignWare XPCS node (with four pcs-mii
sub-nodes) plus two 125 MHz fixed-clock nodes used as GMAC reference
clocks.  The XPCS node and its sub-nodes are disabled by default and are
meant to be completed and enabled at the board level.

A couple of questions about the new nodes below.

> diff --git a/arch/arm64/boot/dts/rockchip/rk3568.dtsi b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> index 3bc653f027f1f..989e164c0eb39 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> @@ -110,6 +110,51 @@ sata0: sata@fc000000 {
>  		status = "disabled";
>  	};
>  
> +	xpcs: pcs@fda00000 {
> +		compatible = "rockchip,rk3568-xpcs";
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		reg = <0x0 0xfda00000 0x0 0x200000>;
> +		clocks = <&cru PCLK_XPCS>, <&cru CLK_XPCS_EEE>;
> +		clock-names = "csr", "eee";
> +		power-domains = <&power RK3568_PD_PIPE>;
> +		status = "disabled";

[Severity: Medium]
Does this node validate against the binding added earlier in the same
series?  Documentation/devicetree/bindings/net/pcs/rockchip-dwxpcs.yaml
lists phys and phy-names unconditionally:

required:
  - compatible
  - reg
  - "#address-cells"
  - "#size-cells"
  - clocks
  - clock-names
  - phys
  - phy-names
  - power-domains

The node here supplies neither, and dt-validate does not skip nodes with
status = "disabled", so dtbs_check should report "'phys' is a required
property" and "'phy-names' is a required property" for every rk3568 dtb
that includes this dtsi.

At the tip of the series only rk3568-photonicat.dts fills them in:

&xpcs {
	status = "okay";
	phys = <&combphy2 PHY_TYPE_SGMII>;
	phy-names = "serdes";
};

so rk3568-evb, rk3568-rock-3a, rk3568-roc-pc, rk3568-radxa-cm3j,
rk3568-wolfvision-pf5 and friends would still be missing them.

If which combphy carries SGMII is genuinely a board-level choice, should
phys/phy-names be moved out of the unconditional required: list in the
binding instead, or should the dtsi provide a default?

> +
> +		xpcs_mii0: pcs-mii@0 {
> +			reg = <0>;
> +			status = "disabled";
> +		};

[Severity: Low]
This isn't a bug, just a note for the record: at this commit there is no
in-tree consumer of "rockchip,rk3568-xpcs" or of the pcs-mii sub-nodes.
Both arrive later in the same series - xpcs_rk_of_ids in
drivers/net/pcs/pcs-xpcs-rk.c gains the compatible, and rk_pcs_init() in
drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c parses pcs-handle and
calls xpcs_rk_create().  With the nodes disabled by default the
intermediate state looks harmless, so nothing needs changing here.

> +
> +		xpcs_mii1: pcs-mii@1 {
> +			reg = <1>;
> +			status = "disabled";
> +		};
> +
> +		xpcs_mii2: pcs-mii@2 {
> +			reg = <2>;
> +			status = "disabled";
> +		};
> +
> +		xpcs_mii3: pcs-mii@3 {
> +			reg = <3>;
> +			status = "disabled";
> +		};
> +	};
> +
> +	xpcs_gmac0_clk: xpcs-gmac0-clock {
> +		compatible = "fixed-clock";
> +		clock-frequency = <125000000>;
> +		clock-output-names = "clk_gmac0_xpcs_mii";
> +		#clock-cells = <0>;
> +	};
> +
> +	xpcs_gmac1_clk: xpcs-gmac1-clock {
> +		compatible = "fixed-clock";
> +		clock-frequency = <125000000>;
> +		clock-output-names = "clk_gmac1_xpcs_mii";
> +		#clock-cells = <0>;
> +	};

[Severity: Low]
These two node names take the deprecated branch of the fixed-clock
$nodename schema.  Documentation/devicetree/bindings/clock/fixed-clock.yaml
has:

  $nodename:
    anyOf:
      - description:
          Preferred name is 'clock-<freq>' with <freq> being the output
          frequency as defined in the 'clock-frequency' property.
        pattern: "^clock-([0-9]+|[a-z0-9-]+)$"
      - description: Any name allowed
        deprecated: true

xpcs-gmac0-clock and xpcs-gmac1-clock do not match the preferred
pattern, so they land on the "Any name allowed" branch.  Newer Rockchip
dtsi files use the preferred form already, for example rk3528.dtsi with
xin24m: clock-xin24m and gmac0_clk: clock-gmac50m.

Could these be named clock-xpcs-gmac0 and clock-xpcs-gmac1?  The labels
xpcs_gmac0_clk / xpcs_gmac1_clk and all references would stay the same.

>  	pipe_phy_grf0: syscon@fdc70000 {
>  		compatible = "rockchip,rk3568-pipe-phy-grf", "syscon";
>  		reg = <0x0 0xfdc70000 0x0 0x1000>;