[PATCH v3 05/12] dt_bindings: rs485: Add receiver enable polarity

[PATCH v3 05/12] dt_bindings: rs485: Add receiver enable polarity

[Ilpo Järvinen]

Add polarity property for receiver enable. Some UARTs have
separate enable pins for tx (RTS or DE) and rx (RE). As most
RS485 transceivers have !RE pin, the default is active low in
contrast to rs485-rts-active-low that defaults to active high.

Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 Documentation/devicetree/bindings/serial/rs485.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml
index 0c9fa694f85c..f2c9c9fe6aa7 100644
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -33,6 +33,11 @@ properties:
     description: drive RTS low when sending (default is high).
     $ref: /schemas/types.yaml#/definitions/flag
 
+  rs485-rx-active-high:
+    description: Polarity of receiver enable signal (when separate from RTS).
+      True indicates active high (default is low).
+    $ref: /schemas/types.yaml#/definitions/flag
+
   linux,rs485-enabled-at-boot-time:
     description: enables the rs485 feature at boot time. It can be disabled
       later with proper ioctl.
-- 
2.30.2