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References: <20210729201100.3994-1-linux.amoon@gmail.com> <20210729201100.3994-4-linux.amoon@gmail.com>
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From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Tue, 3 Aug 2021 22:45:13 +0200
Message-ID: <CAFBinCAVaaXd+jXBtA9RETP5AavOfeUVZLkU1ohGT2Lmx+H1cw@mail.gmail.com>
Subject: Re: [PATCHv1 3/3] net: stmmac: dwmac-meson8b: Add reset controller
 for ethernet phy
To:     Anand Moon <linux.amoon@gmail.com>
Cc:     netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        devicetree@vger.kernel.org, Jerome Brunet <jbrunet@baylibre.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Emiliano Ingrassia <ingrassia@epigenesys.com>
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Hi Anand,

On Thu, Jul 29, 2021 at 10:11 PM Anand Moon <linux.amoon@gmail.com> wrote:
>
> Add reset controller for Ethernet phy reset on every boot for
> Amlogic SoC.
I think this description does not match what's going on inside the SoC:
- for all SoCs earlier than GXL the PHY is external so the reset for
the PHY is a GPIO
- the reset line you are passing in the .dts belongs to the Ethernet
controller on SoCs earlier than GXL
- I *believe* that the rset line which you're passing in the .dts
belongs to the Ethernet controller AND the built-in MDIO mux on GXL
and newer, see also [0]
- from how the PRG_ETH registers work I doubt that these are connected
to a reset line (as they're managing mostly delays and protocol - so I
don't see what would be reset). This is speculation though.


Best regards,
Martin


[0] https://lore.kernel.org/linux-amlogic/553e127c-9839-d15b-d435-c01f18c7be48@gmail.com/