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[v4,06/13] dt_bindings: rs485: Add receiver enable polarity

Message ID 20220425143410.12703-7-ilpo.jarvinen@linux.intel.com
State New
Headers show
Series None | expand

Commit Message

Ilpo Järvinen April 25, 2022, 2:34 p.m. UTC
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(+)
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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
     description: enables the rs485 feature at boot time. It can be disabled
       later with proper ioctl.