diff --git a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
index 865be05083c3..c69f8464cdf3 100644
--- a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
@@ -9,9 +9,6 @@ maintainers:
 
 title: STMicroelectronics STM32 USART bindings
 
-allOf:
-  - $ref: rs485.yaml
-
 properties:
   compatible:
     enum:
@@ -40,6 +37,8 @@ properties:
 
   uart-has-rtscts: true
 
+  rx-tx-swap: true
+
   dmas:
     minItems: 1
     maxItems: 2
@@ -66,13 +65,23 @@ properties:
   linux,rs485-enabled-at-boot-time: true
   rs485-rx-during-tx: true
 
-if:
-  required:
-    - st,hw-flow-ctrl
-then:
-  properties:
-    cts-gpios: false
-    rts-gpios: false
+allOf:
+  - $ref: rs485.yaml#
+  - $ref: serial.yaml#
+  - if:
+      required:
+        - st,hw-flow-ctrl
+    then:
+      properties:
+        cts-gpios: false
+        rts-gpios: false
+  - if:
+      properties:
+        compatible:
+          const: st,stm32-uart
+    then:
+      properties:
+        rx-tx-swap: false
 
 required:
   - compatible