[PATCH net-next v8 5/9] ARM64: dts: marvell: Fix some common switch mistakes

[Vladimir Oltean]

On Tue, Nov 14, 2023 at 12:36:00AM +0100, Linus Walleij wrote:
> diff --git a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> index 9eab2bb22134..66cd98b67744 100644
> --- a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> +++ b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
> @@ -304,7 +304,13 @@ phy1: ethernet-phy at 1 {
>  		reg = <1>;
>  	};
>  
> -	/* switch nodes are enabled by U-Boot if modules are present */
> +	/*
> +	 * NOTE: switch nodes are enabled by U-Boot if modules are present
> +	 * DO NOT change this node name (switch0 at 10) even if it is not following
> +	 * conventions! Deployed U-Boot binaries are explicitly looking for
> +	 * this node in order to augment the device tree!
> +	 * Also do not touch the "ports" or "port at n" nodes. These are also ABI.
> +	 */
>  	switch0 at 10 {
>  		compatible = "marvell,mv88e6190";
>  		reg = <0x10>;
> @@ -430,6 +436,7 @@ port-sfp at a {
>  		};
>  	};
>  
> +	/* NOTE: this node name is ABI, don't change it! */
>  	switch0 at 2 {
>  		compatible = "marvell,mv88e6085";
>  		reg = <0x2>;
> @@ -497,6 +504,7 @@ port at 5 {
>  		};
>  	};
>  
> +	/* NOTE: this node name is ABI, don't change it! */
>  	switch1 at 11 {
>  		compatible = "marvell,mv88e6190";
>  		reg = <0x11>;
> @@ -622,6 +630,7 @@ port-sfp at a {
>  		};
>  	};
>  
> +	/* NOTE: this node name is ABI, don't change it! */
>  	switch1 at 2 {
>  		compatible = "marvell,mv88e6085";
>  		reg = <0x2>;
> @@ -689,6 +698,7 @@ port at 5 {
>  		};
>  	};
>  
> +	/* NOTE: this node name is ABI, don't change it! */
>  	switch2 at 12 {
>  		compatible = "marvell,mv88e6190";
>  		reg = <0x12>;
> @@ -805,6 +815,7 @@ port-sfp at a {
>  		};
>  	};
>  
> +	/* NOTE: this node name is ABI, don't change it! */
>  	switch2 at 2 {
>  		compatible = "marvell,mv88e6085";
>  		reg = <0x2>;

I wouldn't spam the device tree with all these comments; doing so gives
a false sense of completeness. Code inspection shows that the "port-sfp at a"
node name is also established ABI, but there isn't any explicit comment
to point that out. I think a single comment that uses plural to refer to
all nodes should be enough.

Also, doesn't the comment go better along with the patch that changes
the switch compatible strings, rather than with the patch that actually
fixes what can be fixed (ethernet-phy node names)?