On Thu, Apr 28, 2016 at 11:23:15PM +0200, Andrew Lunn wrote:

On Thu, Apr 28, 2016 at 04:03:57PM -0500, Josh Cartwright wrote:

quoted

On Thu, Apr 28, 2016 at 08:59:32PM +0200, Andrew Lunn wrote:

quoted

On Thu, Apr 28, 2016 at 01:55:27PM -0500, Nathan Sullivan wrote:

quoted

On Thu, Apr 28, 2016 at 08:43:03PM +0200, Andrew Lunn wrote:

quoted

quoted

I agree that is a valid fix for AT91, however it won't solve our problem, since
we have no children on the second ethernet MAC in our devices' device trees. I'm
starting to feel like our second MAC shouldn't even really register the MDIO bus
since it isn't being used - maybe adding a DT property to not have a bus is a
better option?

status = "disabled"

would be the unusual way.

      Andrew

Oh, sorry, I meant we use both MACs on Zynq, however the PHYs are on the MDIO
bus of the first MAC.  So, the second MAC is used for ethernet but not for MDIO,
and so it does not have any PHYs under its DT node.  It would be nice if there
were a way to tell macb not to bother with MDIO for the second MAC, since that's
handled by the first MAC.

Yes, exactly, add support for status = "disabled" in the mdio node.

Unfortunately, the 'macb' doesn't have a "mdio node", or alternatively:
the node representing the mdio bus is the same node which represents the
macb instance itself.  Setting 'status = "disabled"' on this node will
just prevent the probing of the macb instance.

:-(

It is very common to have an mdio node within the MAC node, for example imx6sx-sdb.dtsi

Okay, I think that makes sense.  I think, then, perhaps the solution to
our problem is to:

  1. Modify the macb driver to support an 'mdio' node. (And adjust the
     binding document accordingly).  If the node is found, it's used for
     of_mdiobus_register() w/o any of the manual scan madness.
  2. For backwards compatibility, in the case where an 'mdio' node does
     not exist, leave the existing behavior the way it is now
     (of_mdiobus_register() followed by manual scan) [perhaps warn of
     deprecation as well?]
  3. Update binding docs to reflect the above.

In this way, for our usecase, the 'status = "disabled"' in the newly
created 'mdio' node isn't necessary.  It's sufficient for the node to
exist and be empty.

&fec1 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet1>;
        phy-supply = <&reg_enet_3v3>;
        phy-mode = "rgmii";
        phy-handle = <&ethphy1>;
        status = "okay";

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

                ethphy1: ethernet-phy@1 {
                        reg = <1>;
                };

                ethphy2: ethernet-phy@2 {
                        reg = <2>;
                };
        };
};

&fec2 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet2>;
        phy-mode = "rgmii";
        phy-handle = <&ethphy2>;
        status = "okay";
};

This even has the two phys on one bus, as you described...

Yep...looks nearly exactly the same case.

Thanks,
  Josh