Re: [PATCH 1/5] dt-bindings: net: macb: Add SiFive FU740-C000 support

[Conor Dooley <conor@kernel.org>]

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On Fri, Feb 20, 2026 at 04:27:05PM +0800, Max Hsu wrote:
> Add the SiFive FU740-C000 ethernet controller compatible string to the
> Cadence MACB binding documentation.
> 
> The FU740 ethernet controller uses the same GEMGXL management block as
> the FU540, which is tightly coupled with the Cadence MACB IP. This
> follows the SiFive IP versioning scheme which requires SoC-specific
> compatible strings for proper hardware identification.

Your rationale for this change is misguided, as this is not a SiFive IP,
so that document does not apply. On the other hand, the general rules
for devicetrees require this so this just means a change in the
rationale provided.

> 
> Signed-off-by: Max Hsu <max.hsu@sifive.com>
> ---
>  Documentation/devicetree/bindings/net/cdns,macb.yaml | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/net/cdns,macb.yaml b/Documentation/devicetree/bindings/net/cdns,macb.yaml
> index cb14c35ba996..b46dde1da170 100644
> --- a/Documentation/devicetree/bindings/net/cdns,macb.yaml
> +++ b/Documentation/devicetree/bindings/net/cdns,macb.yaml
> @@ -63,6 +63,7 @@ properties:
>            - mobileye,eyeq5-gem        # Mobileye EyeQ5 SoCs
>            - raspberrypi,rp1-gem       # Raspberry Pi RP1 gigabit ethernet interface
>            - sifive,fu540-c000-gem     # SiFive FU540-C000 SoC
> +          - sifive,fu740-c000-gem     # SiFive FU740-C000 SoC

I don't think this is right, since it is identical to the one on the
fu540 (as evidenced by how it has worked until now and the contents of
your driver change). I think you should add the fu740 with a fallback to
the fu540, like the devices from Microchip that fall back to the
microchip,sama7g5-gem. The rest of the changes to the driver and binding
can then be dropped as they'll be redundant.

Thanks,
Conor.

pw-bot: changes-requested

>  
>        - items:
>            - enum:
> @@ -74,7 +75,7 @@ properties:
>      minItems: 1
>      items:
>        - description: Basic register set
> -      - description: GEMGXL Management block registers on SiFive FU540-C000 SoC
> +      - description: GEMGXL Management block registers on SiFive FU540/FU740 SoCs
>  
>    interrupts:
>      minItems: 1
> @@ -181,7 +182,9 @@ allOf:
>          properties:
>            compatible:
>              contains:
> -              const: sifive,fu540-c000-gem
> +              enum:
> +                - sifive,fu540-c000-gem
> +                - sifive,fu740-c000-gem
>      then:
>        properties:
>          reg:
> 
> -- 
> 2.43.0
> 

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