On Mon, Aug 21, 2017 at 04:23:21PM +0200, Andrew Lunn wrote:

quoted

All muxes are mostly always represented the same way afaik, or do you
want to simply introduce a new compatible / property?

+      	  mdio-mux {
+		compatible = "allwinner,sun8i-h3-mdio-switch";
+		mdio-parent-bus = <&mdio_parent>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		internal_mdio: mdio at 1 {
			reg = <1>;
-			clocks = <&ccu CLK_BUS_EPHY>;
-			resets = <&ccu RST_BUS_EPHY>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			int_mii_phy: ethernet-phy at 1 {
+				compatible = "ethernet-phy-ieee802.3-c22";
+				reg = <1>;
+				clocks = <&ccu CLK_BUS_EPHY>;
+				resets = <&ccu RST_BUS_EPHY>;
+				phy-is-integrated;
+			};
+		};
+		mdio: mdio at 0 {
+			reg = <0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
 		};
 		
Hi Maxim

Anybody who knows the MDIO-mux code/binding, knows that it is a run
time mux. You swap the mux per MDIO transaction. You can access all
the PHY and switches on the mux'ed MDIO bus.

However here, it is effectively a boot-time MUX. You cannot change it
on the fly. What happens when somebody has a phandle to a PHY on the
internal and a phandle to a phy on the external? Does the driver at
least return -EINVAL, or -EBUSY? Is there a representation which
eliminates this possibility?

Exactly you can change it on the fly, but you need to reset the MAC for enabling the new configuration.
The stmmac driver does not handle mdio-mux. It is why I have a patch which automaticly select parent MDIO node of the PHY node.

For representation we could keep the current. (With a big comment stating that it is a switch)

We can also add a mdio-switch type node, or add a mdio-switch property to mdio-mux.

Regards