[PATCH] arm64: imx8mp: Inhibit DTC warning on DH i.MX8MP DHCOM rev.100 DTO

[Fabio Estevam]

On Sat, Nov 4, 2023 at 9:04 PM Marek Vasut <marex at denx.de> wrote:
>
> Inhibit DTC warning in imx8mp-dhcom-pdk3-overlay-rev100.dts:
> "
> arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (reg_format): /fragment at 0/__overlay__:reg: property has invalid length (4 bytes) (#address-cells == 2, #size-cells == 1)
> arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (avoid_default_addr_size): /fragment at 0/__overlay__: Relying on default #address-cells value
> arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (avoid_default_addr_size): /fragment at 0/__overlay__: Relying on default #size-cells value
> "
>
> The DTO overwrites the 'reg' property of an ethernet PHY and is only
> used on specific combination of old prototype SoM and old prototype
> PDK3 carrier board, which had incorrectly placed pull resistor, which
> made the PHY change its MDIO address in that specific combination and
> which is already fixed on production hardware.
>
> The DTO is implemented in this simple manner because if it contained a
> full MDIO bus node reference to define #address-cells and #size-cells,
> it would also require a full new copy of the PHY node, i.e.
> ethernet-phy at 5 { ... reg = <5>; ... }, to avoid DTC warnings about
> mismatch between node unit and reg value. The node unit in SoM DT is
> ethernet-phy at 7 { ... }; .
>
> This simpler approach avoids unnecessary duplication without adverse
> side effects.
>
> Reported-by: Fabio Estevam <festevam at denx.de>
> Reported-by: Sean Anderson <seanga2 at gmail.com>
> Signed-off-by: Marek Vasut <marex at denx.de>

Reviewed-by: Fabio Estevam <festevam at gmail.com>