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From: Lukas Wunner <lukas@wunner.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>, Rob Herring <robh+dt@kernel.org>
Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru>,
	Giulio Benetti <giulio.benetti@micronovasrl.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Christoph Muellner <christoph.muellner@theobroma-systems.com>,
	linux-serial@vger.kernel.org, devicetree@vger.kernel.org
Subject: [PATCH v2 3/4] dt-bindings: serial: Add binding for rs485 bus termination GPIO
Date: Tue, 12 May 2020 14:40:03 +0200	[thread overview]
Message-ID: <3d32e182ebefce6144844adf12fe481a35580633.1589285874.git.lukas@wunner.de> (raw)
In-Reply-To: <cover.1589285873.git.lukas@wunner.de>

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:
   rs485-rx-during-tx:
    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
-- 
2.26.2


  parent reply	other threads:[~2020-05-12 12:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-12 12:40 [PATCH v2 0/4] " Lukas Wunner
2020-05-12 12:40 ` [PATCH v2 1/4] serial: 8250: Avoid error message on reprobe Lukas Wunner
2020-05-12 13:45   ` Andy Shevchenko
2020-05-12 12:40 ` [PATCH v2 2/4] serial: Allow uart_get_rs485_mode() to return errno Lukas Wunner
2020-05-12 13:46   ` Andy Shevchenko
2020-05-12 12:40 ` Lukas Wunner [this message]
2020-05-12 12:40 ` [PATCH v2 4/4] serial: 8250: Support rs485 bus termination GPIO Lukas Wunner
2020-05-12 14:09   ` Andy Shevchenko

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