diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
index b749c82edebd..194649bb1cfa 100644
--- a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
@@ -76,6 +76,7 @@ additionalProperties:
         output-impedance-ohms:
           enum: [ 33, 50, 66, 100 ]
         power-source:
+          description: I/O voltage in millivolt.
           enum: [ 1800, 2500, 3300 ]
         slew-rate: true
         gpio-hog: true