[3/4] dt-bindings: serial: Add binding for rs485 bus termination GPIO

Message ID eb9737e7b76ac39d9ae38a46e233c0643c31a9cb.1588505407.git.lukas@wunner.de
State New
Headers show
  • Untitled series #39215
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Commit Message

Lukas Wunner May 5, 2020, 2:42 p.m.
Commit e8759ad17d41 ("serial: uapi: Add support for bus termination")
introduced the ability to enable rs485 bus termination from user space.
So far the feature is only used by a single driver, 8250_exar.c, using a
hardcoded GPIO pin specific to Siemens IOT2040 products.

Provide for a more generic solution by allowing specification of an
rs485 bus termination GPIO pin in the device tree.  An upcoming commit
implements support for this pin for any 8250 driver.  The binding is
used in device trees of the "Revolution Pi" PLCs offered by KUNBUS.

[Heiko Stuebner converted the binding to YAML, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Jan Kiszka <jan.kiszka@siemens.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 d4beaf11222d..a9ad17864889 100644
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -43,3 +43,7 @@  properties:
    description: enables the receiving of data even while sending data.
    $ref: /schemas/types.yaml#/definitions/flag
+  rs485-term-gpios:
+    description: GPIO pin to enable RS485 bus termination.
+    maxItems: 1