diff --git a/Documentation/devicetree/bindings/net/mediatek-net.txt b/Documentation/devicetree/bindings/net/mediatek-net.txt
index 6103e5583070b8e0f951a4e3e738852d3e2ece78..7111278adc7e33384e1c3e50e0cd44616fb86725 100644
--- a/Documentation/devicetree/bindings/net/mediatek-net.txt
+++ b/Documentation/devicetree/bindings/net/mediatek-net.txt
@@ -31,7 +31,10 @@ Optional properties:
 Required properties:
 - compatible: Should be "mediatek,eth-mac"
 - reg: The number of the MAC
-- phy-handle: see ethernet.txt file in the same directory.
+- phy-handle: see ethernet.txt file in the same directory and
+	the phy-mode "trgmii" required being provided when reg
+	is equal to 0 and the MAC uses fixed-link to connect
+	with inernal switch such as MT7530.
 
 Example: