linux-kernel - [PATCH v2 1/3] dt-bindings: i2c: gpio: Add 'transition-delay-us' property

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Date: Wed, 29 May 2024 11:17:37 +0200
From: Bastien Curutchet <bastien.curutchet@...tlin.com>
To: Peter Rosin <peda@...ntia.se>,
	Andi Shyti <andi.shyti@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Peter Korsgaard <peter.korsgaard@...co.com>,
	Wolfram Sang <wsa@...nel.org>
Cc: linux-i2c@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Herve Codina <herve.codina@...tlin.com>,
	Christopher Cordahi <christophercordahi@...ometrics.ca>,
	Bastien Curutchet <bastien.curutchet@...tlin.com>
Subject: [PATCH v2 1/3] dt-bindings: i2c: gpio: Add 'transition-delay-us' property

I2C MUXes described by the i2c-gpio-mux sometimes need a significant
amount of time to switch from a bus to another. When a new bus is
selected, the first I2C transfer can fail if it occurs too early. There
is no way to describe this transition delay that has to be waited before
starting the first I2C transfer.

Add a 'transition-delay-us' property that indicates the delay to be
respected before doing the first i2c transfer.

Signed-off-by: Bastien Curutchet <bastien.curutchet@...tlin.com>
---
 Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
index f34cc7ad5a00..20d72c3e1e10 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
@@ -57,6 +57,9 @@ properties:
       last value used.
     $ref: /schemas/types.yaml#/definitions/uint32
 
+  transition-delay-us:
+    description: Delay to wait before doing any transfer when a new bus gets selected.
+
 allOf:
   - $ref: i2c-mux.yaml
 
-- 
2.44.0