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Subject: Re: [PATCHv4 1/5] net: dsa: Support internal phy on 'cpu' port
To: Andrew Lunn <andrew@lunn.ch>
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>,
        Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
        Shawn Guo <shawnguo@kernel.org>, Sascha Hauer <kernel@pengutronix.de>,
        Fabio Estevam <fabio.estevam@nxp.com>, Ian Ray <ian.ray@ge.com>,
        Nandor Han <nandor.han@ge.com>, Rob Herring <robh+dt@kernel.org>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20180116101958.19711-1-sebastian.reichel@collabora.co.uk>
 <20180116101958.19711-2-sebastian.reichel@collabora.co.uk>
 <09a9c406-85c1-0f84-4032-db243f825ca2@gmail.com>
 <20180122205459.GF2467@lunn.ch>
From: Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <3b7fa162-20f9-b31c-b61b-07066fefd196@gmail.com>
Date: Mon, 22 Jan 2018 12:56:44 -0800
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On 01/22/2018 12:54 PM, Andrew Lunn wrote:
>> Note: there is still technically a misreprentation of how the PHY is
>> "attached" to the network device. In your DTSes, you have to have the
>> CPU port have a "phy-handle" to the internal PHY, while technically it
>> should be the i210 which has a "phy-handle" property to that PHY, and
>> even better, if the e1000e/idb drivers were PHYLIB capable, they could
>> manage it directly.
> 
> Hi Florian
> 
> Err, i don't think i agree. But maybe i'm missunderstanding.
> 
> We have two back-to-back PHYs. I would expect the i210 MAC to have a
> phy-handle pointing it its PHY. The CPU port would then point to the
> internal switch PHY.

Is it really a back-to-back PHY? If that is the case, ok, that can
indeed work without magnetics, but this is really an inefficient way to
connect a MAC to a switch, especially when you can do direct (R)GMII
without any PHY in between... If that is the case, then disregard my
comment.

> 
> Or are you suggesting the i210 has two phy-handles, its own and the
> switches?

Not suggesting that, that would be weird.

> 
> 	Andrew
> 


-- 
Florian