[PATCH v4 16/22] dt-bindings: net: Update Freescale TSEC to support "queue-group"

[Bin Meng <bmeng.cn@gmail.com>]

At present the Freescale TSEC node DT bindings doc requires a <reg>
property in the TSEC node. But this might not always be the case.
In the upstream Linux kernel, there is no DT bindings doc for it
but the kernel driver tests a subnode of a name prefixed with
"queue-group", as we can see from gfar_of_init():

  for_each_available_child_of_node(np, child) {
      if (!of_node_name_eq(child, "queue-group"))
  ...

in drivers/net/ethernet/freescale/gianfar.c

Update our DT bindings to describe this alternate description.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>

---

Changes in v4:
- describe "ranges" is required fo the alternate description

Changes in v3:
- add "ranges" in the alternate example

 doc/device-tree-bindings/net/fsl-tsec-phy.txt | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/doc/device-tree-bindings/net/fsl-tsec-phy.txt b/doc/device-tree-bindings/net/fsl-tsec-phy.txt
index a44c5fd9d9..f68980352b 100644
--- a/doc/device-tree-bindings/net/fsl-tsec-phy.txt
+++ b/doc/device-tree-bindings/net/fsl-tsec-phy.txt
@@ -3,12 +3,17 @@
 Properties:
 
   - compatible : Should be "fsl,etsec2" or "gianfar"
-  - reg : Offset and length of the register set for the device
+  - reg : Offset and length of the register set for the device. If this is
+    missing, a subnode with a name prefix "queue-group" must be provided to
+    provide the <reg> property.
   - phy-handle : See ethernet.txt file in the same directory.
   - phy-connection-type : See ethernet.txt file in the same directory. This
     property is only really needed if the connection is of type "rgmii-id",
     "rgmii-rxid" and "rgmii-txid" as all other connection types are detected
     by hardware.
+  - ranges : an <empty> value if subnode "queue-group" is present, specifying
+    that no address translation is required between them TSEC parent node and
+    the child "queue-group" node.
 
 Example:
 	ethernet at 24000 {
@@ -18,6 +23,18 @@ Example:
 		phy-connection-type = "sgmii";
 	};
 
+An alternate description with "queue-group" subnode example:
+	ethernet at 24000 {
+		compatible = "fsl,etsec2";
+		phy-handle = <&phy0>;
+		phy-connection-type = "sgmii";
+		ranges;
+
+		queue-group {
+			reg = <0x24000 0x1000>;
+		};
+	};
+
 Child nodes of the TSEC controller are typically the individual PHY devices
 connected via the MDIO bus (sometimes the MDIO bus controller is separate).
 
-- 
2.25.1