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Date:   Fri, 21 Oct 2022 10:06:25 +0100
From:   "Russell King (Oracle)" <linux@armlinux.org.uk>
To:     Frank Wunderlich <frank-w@public-files.de>
Cc:     Frank Wunderlich <linux@fw-web.de>,
        linux-mediatek@lists.infradead.org,
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        Mark Lee <Mark-MC.Lee@mediatek.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] net: mtk_sgmii: implement mtk_pcs_ops
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On Fri, Oct 21, 2022 at 08:04:51AM +0200, Frank Wunderlich wrote:
> I have no register documentation to check if there is any way to read out pause/duplex setting. Maybe MTK can answer this or extend function later.

I suspect we can probably guess.

Looking at SGMSYS_PCS_CONTROL_1, this is actually the standard BMCR in
the low 16 bits, and BMSR in the upper 16 bits, so:

At address 4, I'd expect the PHYSID.
At address 8, I'd expect the advertisement register in the low 16 bits
and the link partner advertisement in the upper 16 bits.

Can you try an experiment, and in mtk_sgmii_init() try accessing the
regmap at address 0, 4, and 8 and print their contents please?

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