[PATCH 5/8] dt-bindings: serial: stm32: update rts-gpios and cts-gpios

Erwan Le Ray
2020-12-18T19:01:45Z

Update rts-gpios and cts-gpios:
- remove max-items as already defined in serial.yaml
- add a note describing rts-gpios and cts-gpios usage with stm32

Document the use of cts-gpios and rts-gpios for flow control in STM32 UART
controller. These properties can be used instead of 'uart-has-rtscts' or
'st,hw-flow-ctrl' (deprecated) for making use of any gpio pins for flow
control instead of dedicated pins.
It should be noted that both cts-gpios/rts-gpios and 'uart-has-rtscts' or
'st,hw-flow-ctrl' (deprecated) properties cannot co-exist in a design.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>

diff --git a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
index 06d5f251ec88..8631678283f9 100644
--- a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
@@ -50,11 +50,14 @@ properties:
minItems: 1
maxItems: 2

- cts-gpios:
- maxItems: 1
-
- rts-gpios:
- maxItems: 1
+# cts-gpios and rts-gpios properties can be used instead of 'uart-has-rtscts'
+# or 'st,hw-flow-ctrl' (deprecated) for making use of any gpio pins for flow
+# control instead of dedicated pins.
+#
+# It should be noted that both cts-gpios/rts-gpios and 'uart-has-rtscts' or
+# 'st,hw-flow-ctrl' (deprecated) properties cannot co-exist in a design.
+ cts-gpios: true
+ rts-gpios: true

wakeup-source: true

--
2.17.1