diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 17c553123f96..1001d2a6ace8 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -11,6 +11,7 @@ maintainers:
 
 allOf:
   - $ref: serial.yaml#
+  - $ref: rs485.yaml#
 
 properties:
   compatible: