Depending on kernel and bootloader configuration, it's possible that
Realtek ethernet PHY isn't powered on properly. According to the
datasheet, it needs 30ms to power up and then some more time before it
can be used.

Fix that by adding 100ms ramp delay to regulator responsible for
powering PHY.

Fixes: 94dcfdc77fc5 ("arm64: allwinner: pine64-plus: Enable dwmac-sun8i")
Suggested-by: Ondrej Jirman <[email protected]>
Signed-off-by: Jernej Skrabec <[email protected]>
---
Changes from v1:
- Added comment with explanation why delay is needed
- Updated commit message

 arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-plus.dts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-plus.dts 
b/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-plus.dts
index 24f1aac366d6..d5b6e8159a33 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-plus.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-plus.dts
@@ -63,3 +63,12 @@
                reg = <1>;
        };
 };
+
+&reg_dc1sw {
+       /*
+        * Ethernet PHY needs 30ms to properly power up and some more
+        * to initialize. 100ms should be plenty of time to finish
+        * whole process.
+        */
+       regulator-enable-ramp-delay = <100000>;
+};
-- 
2.23.0

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