diff --git a/Documentation/devicetree/bindings/pinctrl/toshiba,visconti-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/toshiba,visconti-pinctrl.yaml
index 19d47fd414bc..a811a643bb88 100644
--- a/Documentation/devicetree/bindings/pinctrl/toshiba,visconti-pinctrl.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/toshiba,visconti-pinctrl.yaml
@@ -42,7 +42,6 @@ patternProperties:
       function:
         description:
           Function to mux.
-        $ref: /schemas/types.yaml#/definitions/string
         enum: [i2c0, i2c1, i2c2, i2c3, i2c4, i2c5, i2c6, i2c7, i2c8,
                spi0, spi1, spi2, spi3, spi4, spi5, spi6,
                uart0, uart1, uart2, uart3, pwm, pcmif_out, pcmif_in]