netdev - Re: [PATCH] net: macb: reject unsupported rgmii delays

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Message-ID: <20200618191017.GI1551@shell.armlinux.org.uk>
Date:   Thu, 18 Jun 2020 20:10:17 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     Helmut Grohne <helmut.grohne@...enta.de>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH] net: macb: reject unsupported rgmii delays

On Thu, Jun 18, 2020 at 12:02:13PM -0700, Florian Fainelli wrote:
> It should not, but that means that when you describe the fixed-link, the
> 'phy-mode' within the local fixed-link node is meant to describe how the
> other side is configured not how you are configured. For some reason I
> did not consider that to be intuitive when I sent out my response, but I
> suppose spelling it out would greatly help.

Right, so in the MAC-to-MAC setup that is being discussed in this
thread, the _local_ side MAC where phy-mode is specified should not
care which of the RGMII modes is specified, because the delays are
a function of "the other side" of the link.

So, the proposal that macb should limit itself to only accepting
"rgmii" in it's _local_ phy-mode property because the _local_ MAC
does not support delays is wrong.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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