Re: [PATCH v10 3/4] dt-bindings: ethernet-phy: add optional brr-mode flag

[Conor Dooley <conor@kernel.org>]

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On Thu, Jul 04, 2024 at 04:04:12PM +0200, Kamil Horák (2N) wrote:
> There is a group of PHY chips supporting BroadR-Reach link modes in
> a manner allowing for more or less identical register usage as standard
> Clause 22 PHY.
> These chips support standard Ethernet link modes as well, however, the
> circuitry is mutually exclusive and cannot be auto-detected.
> The link modes in question are 100Base-T1 as defined in IEEE802.3bw,
> based on Broadcom's 1BR-100 link mode, and newly defined 10Base-T1BRR
> (1BR-10 in Broadcom documents).
> 
> Add optional brr-mode flag to switch the PHY to BroadR-Reach mode.
> 
> Signed-off-by: Kamil Horák (2N) <kamilh@axis.com>

Where did the tags go? There's no mention of why they were dropped.

> ---
>  Documentation/devicetree/bindings/net/ethernet-phy.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> index 8fb2a6ee7e5b..349ae72ebf42 100644
> --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> @@ -93,6 +93,14 @@ properties:
>        the turn around line low at end of the control phase of the
>        MDIO transaction.
>  
> +  brr-mode:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      If set, indicates the network cable interface is alternative one as
> +      defined in the BroadR-Reach link mode specification under 1BR-100 and
> +      1BR-10 names. The driver needs to configure the PHY to operate in
> +      BroadR-Reach mode.

I find this second sentence unclear. Does the driver need to do
configure the phy because this mode is not enabled by default or because
the device will not work outside of this mode.

Cheers,
Conor.

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