Re: phy address in the device tree, vs auto probing

Grant Likely wrote:

quoted

1. What if we just don't specific a phy address with a reg property which would specify to auto probe it and find the phy as illustrated below?


               Ethernet_MAC: ethernet@81000000 {
                       #address-cells = <1>;
                       #size-cells = <1>;
                       phy-handle = <&phy0>;
                       mdio {
                               #address-cells = <1>;
                               #size-cells = <0>;
                               phy0: phy@7 {
                               } ;
                       } ;

2. Or a special value (-1 or something not 0 - 31) in the phy address that specifies to auto probe as illustrated below.
                               phy0: phy@7 {
                                       reg = <-1>;
                               } ;

I don't like abusing the reg property in this way.  I wonder if a new
empty property would be a better way to indicate this.  Maybe
"phy-probe-address;"?  It would also be important to specify in the
binding that only one phy node is allowed when phy-probe-address is
used.

Also, without a known reg the 'phy@7' name is inaccurate.  Drop the @7.

Scott, Andy: any thoughts?

I'm not fond of the -1.  I'd prefer the explicit phy-probe-address property, 
though I don't mind too much using the absence of reg.

-Scott