Re: Re: [PATCH 1/2] dt-bindings: net: rockchip-dwmac: add rk3568 xpcs compatible

On Sat, Dec 03, 2022 at 05:00:15PM +0800, Chukun Pan wrote:

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Actually looking deeper in the TRM, having these registers "just" written
to from the dwmac-glue-layer feels quite a bit like a hack.

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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.

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So this looks more like it wants to be an actual phy-driver.

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@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.

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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