[PATCH v4 1/6] dt-bindings: serial: Add binding for rs485 receiver enable GPIO

[Farouk Bouabid <farouk.bouabid@theobroma-systems.com>]

From: Heiko Stuebner <heiko.stuebner@cherry.de>

RS485 has two signals to control transmissions "driver enable" (DE) and
"receiver enable" (RE). DE is already handled via the uarts RTS signal
while the RE signal on most implementations doesn't get handled
separately at all.

As there still will be cases where this is needed though add a gpio
property for declaring this signal pin.

Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Signed-off-by: Farouk Bouabid <farouk.bouabid@theobroma-systems.com>
---
 Documentation/devicetree/bindings/serial/rs485.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml
index 9418fd66a8e9..b64577036b5c 100644
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -51,6 +51,10 @@ properties:
     description: enables the receiving of data even while sending data.
     $ref: /schemas/types.yaml#/definitions/flag
 
+  rs485-rx-enable-gpios:
+    description: GPIO to handle a separate RS485 receive enable signal
+    maxItems: 1
+
   rs485-term-gpios:
     description: GPIO pin to enable RS485 bus termination.
     maxItems: 1

-- 
2.34.1