[PATCH v7 1/2] dt-bindings: serial: Add rx-tx-swap to stm32-usart

[Martin Devera]

Add new rx-tx-swap property to allow for RX & TX pin swapping.

Signed-off-by: Martin Devera <devik at eaxlabs.cz>
Acked-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
---
v7:
  - fix yaml linter warning
v6: 
  - add version changelog
v5: 
  - yaml fixes based on Rob Herring comments
    - add serial.yaml reference
    - move compatible from 'then' to 'if'
v3:
  - don't allow rx-tx-swap for st,stm32-uart (suggested
    by Fabrice Gasnier)
v2:
  - change st,swap to rx-tx-swap (suggested by Rob Herring)
---
 .../devicetree/bindings/serial/st,stm32-uart.yaml  | 29 ++++++++++++++--------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
index 8631678283f9..68a0f3ce8328 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
-- 
2.11.0