On 08/29/2014 10:31 AM, Jason Gunthorpe wrote:

On Fri, Aug 29, 2014 at 08:35:36AM -0700, S?ren Brinkmann wrote:

quoted

The compatible string is listed as optional property for PHYs. So, not
having one is an option, I guess. But, I'd also prefer to at least keep
the -c22 one, since I saw problems when I tried using -c45 (the Zed phy
should support it...).

-c45 and -c22 use a completely different MDIO protocol, Zed doesn't
have a 10GE port, so it certainly doesn't use -c45.

Most recent 1GbE PHYs should also implement clause 45. It is a nice
improvement if you are using lot of transactions, otherwise clause 45
over clause 22 is suitable and supported by the PHY library (for EEE in
particular).

If there is no compatible string at all the defined default is to use
-c22.

Absolutely, the current binding makes that property optional, but I
think we should make it mandatory instead.

quoted

Also, so far, we haven't had any phy nodes in our Zynq dts files and
Ethernet worked, so the auto-detection there works pretty well
apparently. But it may be problematic if more than a single PHY is on
the MDIO bus, I'd assume.

Phy autodetection has always worked in some cases, but for DT ethernet
bindings it is expected that there is an option to specify an explicit
MDIO bus, and a phy-handle phandle to point to the phy. The phy should
be explicitly called out with the fixed MDIO address specified to
avoid sketchy MDIO address auto probing.

This provides the framework to specify interrupts and register
overrides for the phy in the DT.

Absolutely, on the plus side, avoiding auto-detection also allows you to
have a shorter boot time (usually by a factor of few hundreds of msecs
depending on how the MDIO buses handle errors).
--
Florian