Subject: Re: [PATCH 1/3][v2] net: phy: introduce 1000BASE-KX and 10GBASE-KR

From: Sebastian Hesselbarth <[email-masked]>
Date: Mon, 18 Jan 2016 09:05:38 +0100

On 18.01.2016 08:23, Shaohui Xie wrote:
>>> If you look at the list of possible values for "phy-mode" you'd see
>>> that none of it describes a PHY-to-PHY connection but all are for
>>> MAC-to-PHY connections. Also, names above suggest it already: MII is
>>> short for media _independent_ interface.
>>>
>>> I copy Andrew's concerns and think that neither 10000base-kx nor
>>> 10gbase-kr belong in the list of phy-mode properties.
>>
>> I concur with that as well, if the phy connection does not really matter here,
>> or does not seem like a good fit, maybe we should have a different property, or
>> just define the hardware interface a little differently?
> Right, 'phy-mode' is not a good fit for backplanes, how about a new property like
> 'backplane-mode' or something, like below:

Hmm. We already have a speed property for that you can use for
1000, 10000, 40000. Leaves the media-type, e.g. copper or whatever.

Currently, you fail to convince me that it is required to describe
the media type at all. We have come a long way with different media
without describing the PHY-to-PHY media type.

What makes the backplane setup so special?

Sebastian

>
> --- a/Documentation/devicetree/bindings/net/phy.txt
> +++ b/Documentation/devicetree/bindings/net/phy.txt
> @@ -33,6 +33,9 @@ Optional Properties:
>   - broken-turn-around: If set, indicates the PHY device does not correctly
>     release the turn around line low at the end of a MDIO transaction.
>
> +- backplane-mode: string, operation mode of the backplane PHY;
> +  must be "1000base-kx" for 1000BASE-KX, or "10gbase-kr" for 10GBASE-KR.
> +
>   Example:
>
>   ethernet-phy@0 {
>
> Thank you!
>
> Shaohui
>