[RFC PATCH v5 2/3] Documentation: DT: net: Add Xilinx gmiitorgmii converter device tree binding documentation

[Appana Durga Kedareswara Rao]

Hi Florian,

	Thanks for the review...

> 
> On 08/09/2016 02:34 AM, Kedareswara rao Appana wrote:
> > Device-tree binding documentation for xilinx gmiitorgmii converter.
> >
> > Signed-off-by: Kedareswara rao Appana <appanad at xilinx.com>
> > ---
> > Changes for v5:
> > ---> Fixed Indentation in the example as suggested by Michal.
> > Changes for v4:
> > --> Modified compatible as suggested by Rob.
> > --> Removed underscores from the converter node name as suggested by Rob.
> > Changes for v3:
> > --> None.
> > Changes for v2:
> > --> New patch.
> >
> >  .../devicetree/bindings/net/xilinx_gmii2rgmii.txt  | 38
> > ++++++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> >
> > diff --git
> > a/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > b/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > new file mode 100644
> > index 0000000..5f48793
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > @@ -0,0 +1,38 @@
> > +XILINX GMIITORGMII Converter Driver Device Tree Bindings
> > +--------------------------------------------------------
> > +
> > +The Gigabit Media Independent Interface (GMII) to Reduced Gigabit
> > +Media Independent Interface (RGMII) core provides the RGMII between
> > +RGMII-compliant Ethernet physical media devices (PHY) and the Gigabit
> Ethernet controller.
> > +This core can be used in all three modes of operation(10/100/1000 Mb/s).
> > +The Management Data Input/Output (MDIO) interface is used to
> > +configure the Speed of operation. This core can switch dynamically
> > +between the three Different speed modes by configuring the conveter
> register through mdio write.
> > +
> > +The MDIO is a bus to which the PHY devices are connected.  For each
> > +device that exists on this bus, a child node should be created.  See
> > +the definition of the PHY node in booting-without-of.txt for an
> > +example of how to define a PHY.
> 
> I would skip this paragraph which does not really help with understanding, and
> just refer to Documentation/devicetree/bindings/net/phy.txt for examples.

Sure will fix in the next version...

> 
> 
> > +
> > +This converter sits between the ethernet MAC and the external phy.
> > +MAC <==> GMII2RGMII <==> RGMII_PHY
> > +
> > +Required properties:
> > +- compatible	: Should be "xlnx,gmii-to-rgmii-1.0"
> > +- reg		: The ID number for the phy, usually a small integer
> 
> You would want specify that "reg" property needs to match the one of the PHY
> (specified via phy-handle) you are converting to/from for this "proxy" piece of
> hardware to work.
> 
> If these two have the same "reg" value, is not that going to lead to duplicate
> MDIO devices created on the bus, this may work, based on probing ordering, but
> seems unusual, you don't really need the "reg"
> property here it seems?

The converter Phy address is different from the external phy address.

Regards,
Kedar.


> 
> > +- phy-handle	: Should point to the external phy device.
> > +		  See ethernet.txt file in the same directory.
> > +
> > +Example:
> > +	mdio {
> > +		#address-cells = <1>;
> > +		#size-cells = <0>;
> > +		phy: ethernet-phy at 0 {
> > +			......
> > +		};
> > +		gmiitorgmii: gmiitorgmii at 8 {
> > +			compatible = "xlnx,gmii-to-rgmii-1.0";
> > +			reg = <8>;
> > +			phy-handle = <&phy>;
> > +		};
> > +	};
> >
> 
> 
> --
> Florian