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

Hi Florian,

	Thanks for the review...

On 08/09/2016 02:34 AM, Kedareswara rao Appana wrote:

quoted

Device-tree binding documentation for xilinx gmiitorgmii converter.

Signed-off-by: Kedareswara rao Appana <redacted>
---
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.

quoted

+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.

quoted

+
+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...

quoted

+
+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.

quoted

+- 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@0 {
+			......
+		};
+		gmiitorgmii: gmiitorgmii@8 {
+			compatible = "xlnx,gmii-to-rgmii-1.0";
+			reg = <8>;
+			phy-handle = <&phy>;
+		};
+	};

--
Florian