Re: [PATCH v11 3/3] arm: dts: altera: add Draeger M48 CPU Module

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] net: stmmac: missing snps,dwmac-mdio compatible breaks MDIO registration
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commit d908833e7bbbda78aeaec54305a0979e4a84551f
Author: Petko Manolov <petko.manolov@konsulko.com>

arm: dts: altera: add Draeger M48 CPU Module

M48 is a heterogeneous board made by Draeger that is based on two independent
cpus. This commit adds the device tree for the Altera SoCFPGA Cyclone 5 based
CPU module of the Draeger M48.

> diff --git a/arch/arm/boot/dts/intel/socfpga/socfpga_cyclone5_draeger_m48.dts b/arch/arm/boot/dts/intel/socfpga/socfpga_cyclone5_draeger_m48.dts
> new file mode 100644
> index 0000000000000..314930a52de58
> --- /dev/null
> +++ b/arch/arm/boot/dts/intel/socfpga/socfpga_cyclone5_draeger_m48.dts

[ ... ]

> +&gmac0 {
> +	status = "okay";
> +	phy-mode = "rgmii";
> +	phy-handle = <&ethphy>;
> +
> +	mdio0 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +

[Severity: High]
Does this node need a compatible string to ensure the MDIO bus is registered?

Looking at stmmac_of_get_mdio(), it searches for the MDIO bus by checking if
the MAC is compatible with snps,dwc-qos-ethernet-4.10 or if the MDIO child
node has compatible = "snps,dwmac-mdio". Since neither condition is met,
stmmac_of_get_mdio() returns NULL.

Later in stmmac_mdio_setup(), because phy-handle is defined, the legacy_mdio
fallback evaluates to false and mdio_bus_data is left unallocated. This
causes stmmac_mdio_register() to return early without registering the bus.

Would adding compatible = "snps,dwmac-mdio" to this node prevent the ethernet
interface from failing to probe its PHY?

> +		ethphy: ethernet-phy@0 {
> +			compatible = "ethernet-phy-ieee802.3-c22";
> +			reg = <0>;

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Sashiko AI review · https://sashiko.dev/#/patchset/20261015145804.3632839-1-petko.manolov@konsulko.com?part=3