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Date:   Tue, 18 Apr 2023 13:54:45 -0500
From:   Rob Herring <robh@kernel.org>
To:     Ivan Mikhaylov <fr0st61te@gmail.com>
Cc:     Samuel Mendoza-Jonas <sam@mendozajonas.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Paul Fertser <fercerpav@gmail.com>
Subject: Re: [PATCH 3/4] net/ftgmac100: add mac-address-increment option for
 GMA command from NC-SI
Message-ID: <20230418185445.GA2111443-robh@kernel.org>
References: <20230413002905.5513-1-fr0st61te@gmail.com>
 <20230413002905.5513-4-fr0st61te@gmail.com>
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On Thu, Apr 13, 2023 at 12:29:04AM +0000, Ivan Mikhaylov wrote:
> Add s32 mac-address-increment option for Get MAC Address command from
> NC-SI.
> 
> Signed-off-by: Paul Fertser <fercerpav@gmail.com>
> Signed-off-by: Ivan Mikhaylov <fr0st61te@gmail.com>
> ---
>  Documentation/devicetree/bindings/net/ftgmac100.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ftgmac100.txt b/Documentation/devicetree/bindings/net/ftgmac100.txt
> index 29234021f601..7ef5329d888d 100644
> --- a/Documentation/devicetree/bindings/net/ftgmac100.txt
> +++ b/Documentation/devicetree/bindings/net/ftgmac100.txt
> @@ -22,6 +22,10 @@ Optional properties:
>  - use-ncsi: Use the NC-SI stack instead of an MDIO PHY. Currently assumes
>    rmii (100bT) but kept as a separate property in case NC-SI grows support
>    for a gigabit link.
> +- mac-address-increment: Increment the MAC address taken by GMA command via
> +  NC-SI. Specifies a signed number to be added to the host MAC address as
> +  obtained by the OEM GMA command. If not specified, 1 is used by default
> +  for Broadcom and Intel network cards, 0 otherwise.

This would need to be common. There's been some attempts around how to 
support a base MAC address with a transform per instance. So far it's 
not clear that something in DT works for everyone. Until there's 
something common (if ever), you need platform specific code somewhere to 
handle this. The nvmem binding has had some extensions to support that.

Rob