Re: [RFC PATCH v2 1/4] Documentation: DT: net: Add Xilinx gmiitorgmii converter device tree binding documentation
From: Andrew Lunn
Date: Wed Jul 06 2016 - 10:21:40 EST
> > Hi Kedareswara
> >
> > So looking at the device tree, you have the gmiitorgmii as an mdio
> > device. It will get probed as an mdio device, and from that you know
> > the address on the bus. However, your driver does not actually do
> > this. xilinx_gmii2rgmii.c is just a library of two functions, and does
> > not use any of this device tree information. You device tree binding
> > is completely bogus.
> >
> > What i think is a much more logical structure, and fits the hardware,
> > which is what DT is all about, is to make your driver an mdio driver.
> > Also, have a phy-handle pointing to the PHY in the gmii_to_rgmii node.
> > You then no longer need the exported gmii2rgmii_phyprobe() function.
> >
> > Next, you want gmiitorgmii driver to register a phy. The MAC driver
> > can then look this up using phy-handle:
> >
> > mdio {
> > #address-cells = <1>;
> > #size-cells = <0>;
> >
> > phy: ethernet-phy@0 {
> > reg = <0>;
> > };
> >
> > gmii_to_rgmii: gmii-to-rgmii@8 {
> > compatible = "xlnx,gmiitorgmii";
> > reg = <8>;
> > phy-handle = <&phy>;
> > };
> > };
>
>
> Thanks for your inputs initially we too thought the similar implementation
> But the GMII2RGMII converter contains only one register and it is
> not compatible to the standard ethernet MII interface. Also it doesn't have
> a standard VID and PID registers So, during the mdio bus scan, this device will
> not appear.
Hi Punnaiah
Use missed some subtlety in my description. I did not call the
GMII2RGMII a PHY device, i called it an MDIO device. These are
different things. Go look at the MDIO subsystem to figure out the
difference.
Andrew