[PATCH net-next v3 1/2] net: dt-bindings: add RGMII TX delay configuration to meson8b-dwmac
martin.blumenstingl at googlemail.com
Fri Dec 2 15:32:37 PST 2016
This allows configuring the RGMII TX clock delay. The RGMII clock is
generated by underlying hardware of the the Meson 8b / GXBB DWMAC glue.
The configuration depends on the actual hardware (no delay may be
needed due to the design of the actual circuit, the PHY might add this
Signed-off-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
Tested-by: Neil Armstrong <narmstrong at baylibre.com>
Documentation/devicetree/bindings/net/meson-dwmac.txt | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/Documentation/devicetree/bindings/net/meson-dwmac.txt b/Documentation/devicetree/bindings/net/meson-dwmac.txt
index 89e62dd..f8bc540 100644
@@ -25,6 +25,20 @@ Required properties on Meson8b and newer:
- "clkin0" - first parent clock of the internal mux
- "clkin1" - second parent clock of the internal mux
+Optional properties on Meson8b and newer:
+- amlogic,tx-delay-ns: The internal RGMII TX clock delay (provided
+ by this driver) in nanoseconds. Allowed values
+ are: 0ns, 2ns, 4ns, 6ns.
+ This must be configured when the phy-mode is
+ "rgmii" (typically a value of 2ns is used in
+ this case).
+ When phy-mode is set to "rgmii-id" or
+ "rgmii-txid" the TX clock delay is already
+ provided by the PHY. In that case this
+ property should be set to 0ns (which disables
+ the TX clock delay in the MAC to prevent the
+ clock from going off because both PHY and MAC
+ are adding a delay).
Example for Meson6:
More information about the linux-amlogic