Micrel Phy KSZ8031 clock select setting in dts

[Oliver Graute <oliver.graute@gmail.com>]

Hello,

I try to enable a Micrel KSZ8031 in my imx6ul board device tree. But i'am
struggeling with the setting for KSZPHY_RMII_REF_CLK_SEL BIT(7). In my
revision of this Micrel KSZ8031 Phy the Bit(7) has to be true. The 0x1f
register must be 0x8180.

How can I configure this register setting into my DTS?

I already checked Documentation/devicetree/bindings/net/micrel.txt

but i'am not sure if this still up to date. There where some reworks
after git commit 86dc1342

some other commits related to this Phy clock setting I checked

commit 1fadee0c3
commit b838b4aced

my non working device tree blob for the phy is:

&fec1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_enet1>;
	phy-mode = "rmii";
	rmmi-ref-clk-sel = <1>;
	phy-handle = <&ethphy0>;
	status = "okay";

	mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy0: ethernet-phy@0 {
			compatible = "micrel,ksz8031";
			reg = <0>;
		};
	};
};


some clue how to configure this phy register setting correctly?

Best regards,

Oliver