[PATCH v6 0/3] netdev/of/phy: MDIO bus multiplexer support.

Timur Tabi b04825 at freescale.com
Fri May 25 04:28:40 EST 2012

David Daney wrote:
> Yes.  You may note in the DTS file I attached in the parent (sorry for 
> the fubar mime types), that there are two, almost identical, MDIO 
> masters.  smi0 has two directly attached PHYs.  smi1 goes to the mux, 
> and each child of the mux has four attached PHYs.

I'm till have trouble understanding all this.  I'm just hacking things up
in order to help me understand it, but it's a slow and painful process.

This call in mdio_mux_init() is failing:

	parent_bus = of_mdio_find_bus(parent_bus_node);

It returns NULL.  Here is my MDIO node:

		fman0: fman at 400000 {
			enet0: ethernet at e0000 {
				tbi-handle = <&tbi0>;
				phy-handle = <&phy0>;
				phy-connection-type = "sgmii";

			mdio0: mdio at e1120 {
				gpios = <&gpio0 0 0
					 &gpio0 1 0>;

				tbi0: tbi-phy at 8 {
					reg = <0x8>;
					device_type = "tbi-phy";

				phy0: ethernet-phy at 1c {
					reg = <0x1c>;

What am I missing?  What do I need to do in order to get
of_mdio_find_bus() to return a real value?

Timur Tabi
Linux kernel developer at Freescale

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