[net-next PATCH v3 1/2] dt-bindings: net: ipq4019-mdio: document now supported clock-frequency

[Christian Marangi]

Document support for clock-frequency and add details on why this
property is needed and what values are supported.

>From internal documentation, while other values are supported, the
correct function of the MDIO bus is not assured hence add only the
suggested supported values to the property enum.

Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
---
 .../bindings/net/qcom,ipq4019-mdio.yaml           | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/qcom,ipq4019-mdio.yaml b/Documentation/devicetree/bindings/net/qcom,ipq4019-mdio.yaml
index 3407e909e8a7..0029e197a825 100644
--- a/Documentation/devicetree/bindings/net/qcom,ipq4019-mdio.yaml
+++ b/Documentation/devicetree/bindings/net/qcom,ipq4019-mdio.yaml
@@ -44,6 +44,21 @@ properties:
     items:
       - const: gcc_mdio_ahb_clk
 
+  clock-frequency:
+    description:
+      The MDIO bus clock that must be output by the MDIO bus hardware, if
+      absent, the default hardware values are used.
+
+      MDC rate is feed by an external clock (fixed 100MHz) and is divider
+      internally. The default divider is /256 resulting in the default rate
+      applied of 390KHz.
+
+      To follow 802.3 standard that instruct up to 2.5MHz by default, if
+      this property is not declared and the divider is set to /256, by
+      default 1.5625Mhz is select.
+    enum: [ 390625, 781250, 1562500, 3125000, 6250000, 12500000 ]
+    default: 1562500
+
 required:
   - compatible
   - reg
-- 
2.43.0