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

[Andrew Lunn <andrew@lunn.ch>]

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