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Date:   Sat, 3 Dec 2022 18:27:58 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Chukun Pan <amadeus@jmu.edu.cn>
Cc:     heiko@sntech.de, alexandre.torgue@foss.st.com, davem@davemloft.net,
        david.wu@rock-chips.com, devicetree@vger.kernel.org,
        edumazet@google.com, joabreu@synopsys.com,
        krzysztof.kozlowski+dt@linaro.org, krzysztof.kozlowski@linaro.org,
        kuba@kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        pabeni@redhat.com, peppe.cavallaro@st.com, robh+dt@kernel.org
Subject: Re: Re: [PATCH 1/2] dt-bindings: net: rockchip-dwmac: add rk3568
 xpcs compatible
Message-ID: <Y4uHHiLxSw1sMcTz@lunn.ch>
References: <3689593.Mh6RI2rZIc@diego>
 <20221203090015.16132-1-amadeus@jmu.edu.cn>
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On Sat, Dec 03, 2022 at 05:00:15PM +0800, Chukun Pan wrote:
> > Actually looking deeper in the TRM, having these registers "just" written
> > to from the dwmac-glue-layer feels quite a bit like a hack.
> 
> > The "pcs" thingy referenced in patch2 actually looks more like a real device
> > with its own section in the TRM and own iomem area. This pcs device then
> > itself has some more settings stored in said pipe-grf.
> 
> > So this looks more like it wants to be an actual phy-driver.
> 
> > @Chukun Pan: plase take a look at something like
> > https://elixir.bootlin.com/linux/latest/source/drivers/phy/mscc/phy-ocelot-serdes.c#L398
> > on how phy-drivers for ethernets could look like.
> 
> > Aquiring such a phy from the dwmac-glue and calling phy_set_mode after
> > moving the xpcs_setup to a phy-driver shouldn't be too hard I think.
> 
> Thanks for pointing that out.
> The patch2 is come from the sdk kernel of rockchip.
> The sgmii-phy of RK3568 is designed on nanning combo phy.
> In the sdk kernel, if we want to use sgmii mode, we need
> to modify the device tree in the gmac section like this:
> 
> ```
> &gmac0 {
> 	power-domains = <&power RK3568_PD_PIPE>;
> 	phys = <&combphy1_usq PHY_TYPE_SGMII>;
> 	phy-handle = <&sgmii_phy>;
> 	phy-mode = "sgmii";

phy-mode tells you you are using SGMII. You can tell the generic PHY
driver this which will call the PHY drivers .set_mode().

As said above, there are plenty of examples of this, mvneta and its
comphy, various mscc drivers etc.

	Andrew