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From: Zev Weiss <zev@bewilderbeest.net>
To: linux-i2c@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org
Cc: Zev Weiss <zev@bewilderbeest.net>,
	openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Guenter Roeck <linux@roeck-us.net>, Peter Rosin <peda@axentia.se>
Subject: [PATCH 2/2] dt-bindings: i2c: add nxp,pca9541 release-delay-us property
Date: Mon, 24 Jan 2022 13:38:50 -0800	[thread overview]
Message-ID: <20220124213850.3766-3-zev@bewilderbeest.net> (raw)
In-Reply-To: <20220124213850.3766-1-zev@bewilderbeest.net>

This property can be used to reduce arbitration overhead on busy i2c
busses by retaining ownership for a brief period in anticipation of
another transaction in the near future.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
---
 Documentation/devicetree/bindings/i2c/nxp,pca9541.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt b/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt
index 42bfc09c8918..c755da59d6ec 100644
--- a/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt
+++ b/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt
@@ -6,6 +6,14 @@ Required Properties:
 
   - reg: The I2C address of the device.
 
+Optional Properties:
+
+ - release-delay-us: the number of microseconds to delay before
+   releasing the bus after a transaction.  If unspecified the default
+   is zero (the bus is released immediately).  Non-zero values can
+   reduce arbitration overhead for back-to-back transactions, at the
+   cost of delaying the other master's access to the bus.
+
   The following required properties are defined externally:
 
   - I2C arbitration bus node. See i2c-arb.txt in this directory.
@@ -13,9 +21,11 @@ Required Properties:
 
 Example:
 
+	#include <dt-bindings/mux/mux.h>
 	i2c-arbitrator@74 {
 		compatible = "nxp,pca9541";
 		reg = <0x74>;
+		release-delay-us = <20000>;
 
 		i2c-arb {
 			#address-cells = <1>;
-- 
2.34.1


      reply	other threads:[~2022-01-25  0:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-24 21:38 [PATCH 0/2] ic2: mux: pca9541: add delayed-release support Zev Weiss
2022-01-24 21:38 ` Zev Weiss [this message]

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