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Date:   Thu, 3 Jun 2021 17:12:31 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Pali =?iso-8859-1?Q?Roh=E1r?= <pali@kernel.org>
Cc:     Igal Liberman <Igal.Liberman@freescale.com>,
        Shruti Kanetkar <Shruti@freescale.com>,
        Emil Medve <Emilian.Medve@freescale.com>,
        Scott Wood <oss@buserror.net>,
        Rob Herring <robh+dt@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Madalin Bucur <madalin.bucur@nxp.com>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: Unsupported phy-connection-type sgmii-2500 in
 arch/powerpc/boot/dts/fsl/t1023rdb.dts
Message-ID: <YLjxX/XPDoRRIvYf@lunn.ch>
References: <20210603143453.if7hgifupx5k433b@pali>
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On Thu, Jun 03, 2021 at 04:34:53PM +0200, Pali Roh?r wrote:
> Hello!
> 
> In commit 84e0f1c13806 ("powerpc/mpc85xx: Add MDIO bus muxing support to
> the board device tree(s)") was added following DT property into DT node:
> arch/powerpc/boot/dts/fsl/t1023rdb.dts fm1mac3: ethernet@e4000
> 
>     phy-connection-type = "sgmii-2500";
> 
> But currently kernel does not recognize this "sgmii-2500" phy mode. See
> file include/linux/phy.h. In my opinion it should be "2500base-x" as
> this is mode which operates at 2.5 Gbps.
> 
> I do not think that sgmii-2500 mode exist at all (correct me if I'm
> wrong).

Kind of exist, unofficially. Some vendors run SGMII over clocked at
2500. But there is no standard for it, and it is unclear how inband
signalling should work. Whenever i see code saying 2.5G SGMII, i
always ask, are you sure, is it really 2500BaseX? Mostly it gets
changed to 2500BaseX after review.

PHY mode sgmii-2500 does not exist in mainline.

	Andrew