[PATCH 1/2] dt-bindings: serial: rs485: Add transceiver interface select GPIO

[Tapio Reijonen]

Multiprotocol transceivers such as the LTC2873 provide both an RS232
and an RS485 interface on the same bus pins and choose between them
with an interface select input: on the LTC2873 a logic low on the
485/232 pin enables RS232 mode and a high enables RS485 mode.

Add an optional rs485-select-gpios property for that input, next to
the existing rs485-term-gpios and rs485-rx-during-tx-gpios. The active
state selects the RS485 interface, the inactive state selects the
transceiver's alternative interface, RS232 on the LTC2873.

Assisted-by: LLM
Signed-off-by: Tapio Reijonen <tapio.reijonen@xxxxxxxxxxx>
---
 Documentation/devicetree/bindings/serial/rs485.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml
index b93254ad2a287ad496f791e3ee90eb9defa0609d..2b5fd405e164f308b6036331edce7eb61da2f3ff 100644
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -60,6 +60,14 @@ properties:
       the active state enables RX during TX.
     maxItems: 1
 
+  rs485-select-gpios:
+    description: GPIO connected to the interface select input of a
+      multiprotocol transceiver that provides an RS485 interface and an
+      alternative interface, typically RS232, on the same bus pins. The
+      active state selects the RS485 interface, the inactive state selects
+      the alternative interface.
+    maxItems: 1
+
 additionalProperties: true
 
 ...

-- 
2.47.3