Re: [PATCH net-next v6 3/3] arm64: dts: renesas: r8a779g0: Add gPTP node

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Device Tree Resource Conflict: Overlapping memory regions for gptp and tsn0 nodes will cause -EBUSY probe failures.
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--- Patch [3]: [PATCH net-next v6 3/3] arm64: dts: renesas: r8a779g0: Add gPTP node ---
commit bb4e1d1111c141906839e9f11b82a931aa6c6fd6
Author: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

arm64: dts: renesas: r8a779g0: Add gPTP node

This commit adds a new gPTP node to the r8a779g0 device tree, sharing the
module between the RAVB and RTSN Ethernet devices on the SoC.

> diff --git a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
> index 82a7278836e57..b9b860ef70351 100644
> --- a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi

[ ... ]

> @@ -589,6 +589,15 @@ tmu4: timer@ffc00000 {
>  			status = "disabled";
>  		};
>  
> +		gptp: ptp@e6449000 {
> +			compatible = "renesas,r8a779g0-gptp", "renesas,rcar-gen4-gptp";
> +			reg = <0 0xe6449000 0 0x500>;
> +			clocks = <&cpg CPG_MOD 2723>;
> +			power-domains = <&sysc R8A779G0_PD_ALWAYS_ON>;
> +			resets = <&cpg 2723>;
> +			status = "disabled";
> +		};
> +
>  		tsn0: ethernet@e6460000 {
>  			compatible = "renesas,r8a779g0-ethertsn", "renesas,rcar-gen4-ethertsn";
>  			reg = <0 0xe6460000 0 0x7000>,

[Severity: Medium]
Will this overlapping memory region cause a resource conflict during probe?

The new gptp node maps the memory region at 0xe6449000. However, the existing
tsn0 node directly below it already claims this exact same region in its reg
property:

arch/arm64/boot/dts/renesas/r8a779g0.dtsi:tsn0: ethernet@e6460000 {
            reg = <0 0xe6460000 0 0x7000>,
                  <0 0xe6449000 0 0x500>;
            reg-names = "tsnes", "gptp";

If a board file enables both the tsn0 and gptp nodes, whichever driver probes
second is likely to fail with an -EBUSY error because request_mem_region()
enforces exclusive access.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260803095232.3527111-1-niklas.soderlund+renesas@ragnatech.se?part=3