The pca953x driver requests a 'vcc' supply, producing:
  pca953x 0-0020: supply vcc not found, using dummy regulator

The PCA9655 (PCA9555-compatible) expander is powered by the same
always-on 3.3V rail as the other I2C devices on the bus.  Add
vcc-supply = <&reg_3p3v> to silence the warning.

Fixes: ced8025b569e ("ARM: dts: armada388-helios4")
Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <redacted>
---
 arch/arm/boot/dts/marvell/armada-388-helios4.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/marvell/armada-388-helios4.dts b/arch/arm/boot/dts/marvell/armada-388-helios4.dts
index 05540b8012c2..cf0432a0e71a 100644
--- a/arch/arm/boot/dts/marvell/armada-388-helios4.dts
+++ b/arch/arm/boot/dts/marvell/armada-388-helios4.dts

@@ -169,6 +169,7 @@ expander0: gpio-expander@20 {
 					gpio-controller;
 					#gpio-cells = <2>;
 					reg = <0x20>;
+					vcc-supply = <&reg_3p3v>;
 					pinctrl-names = "default";
 					pinctrl-0 = <&pca0_pins>;
 					interrupt-parent = <&gpio0>;

-- 
2.55.0