Subject: Re: [PATCH v2 5/7] powerpc/corenet: Add MDIO bus muxing support to the board device tree(s)

From: Scott Wood <[email-masked]>
Date: Wed, 30 Jul 2014 21:30:05 -0500

On Wed, 2014-07-30 at 16:52 -0500, Emil Medve wrote:
> Hello Scott,
> 
> 
> On 07/29/2014 02:58 PM, Scott Wood wrote:
> > On Mon, 2014-07-28 at 06:51 +0000, Emil Medve wrote:
> >> Hello Scott,
> >>
> >>
> >> Scott Wood <scottwood <at> freescale.com> writes:
> >>> On Wed, 2014-07-16 at 15:17 -0500, Shruti Kanetkar wrote:
> >>>> +			mdio <at> fd000 {
> >>>> +				/* For 10g interfaces */
> >>>> +				phy_xaui_slot1: xaui-phy <at> slot1 {
> >>>> +					status = "disabled";
> >>>> +					compatible = "ethernet-phy-ieee802.3-c45";
> >>>> +					reg = <0x7>; /* default switch setting on slot1 of AMC2PEX */
> >>>> +				};
> >>>
> >>> Why xaui-phy and not ethernet-phy?
> >>>
> >>> As for the device_type discussion from v1, there is a generic binding
> >>> that says device_type "should" be ethernet-phy.
> >>
> >> I have no strong feelings about this and we can use ethernet-phy, but:
> >>
> >> 1. The binding is old/stale (?) as it still uses device_type and the kernel
> >> doesn't seem to use anymore the device_type for PHY(s)
> > 
> > Yes.
> > 
> >> 2. The binding asks "ethernet-phy" for the device_type property, not for the
> >> name. As such TBI PHY(s) use (upstream) the tbi-phy@ node name
> > 
> > It shows ethernet-phy as the name in the example.  ePAPR urges generic
> > node names (this was also a recommendation for IEEE1275), and has
> > ethernet-phy on the preferred list.  Is a xaui-phy not an ethernet phy?
> 
> So you thinking somebody should cleanup all the sgmii-phy and tbi-phy
> node names, huh?

No, I was just wondering why we're adding yet another name, and whether
there's any value in it.

> It seems that a number of tbi-phy instances slipped by you:
> 
> 1be62c6 powerpc/mpc85xx: Add BSC9132 QDS Support
> bf57aeb powerpc/85xx: add the P1020RDB-PD DTS support
> 8a6be2b powerpc/85xx: Add TWR-P1025 board support

tbi-phy is existing practice.  xaui-phy isn't.

> >>>> +			mdio0: mdio <at> fc000 {
> >>>> +			};
> >>>
> >>> Why is the empty node needed?
> >>
> >> For the label
> > 
> > For mdio-parent-bus, or is there some other dts layer that makes this
> > node non-empty?
> 
> 'powerpc/corenet: Create the dts components for the DPAA FMan' -
> http://patchwork.ozlabs.org/patch/370872

Why does this patch define the mdio0 label for mdio@e1120, but not
define a label for any other node?

>  and 'powerpc/corenet: Add DPAA
> FMan support to the SoC device tree(s)' -
> http://patchwork.ozlabs.org/patch/370868 add content to said node

This one adds content to some mdio nodes, none of which are mdio@fc000
or &mdio0.

-Scott