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From: Heiner Kallweit <hkallweit1@gmail.com>
To: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Wolfram Sang <wsa@kernel.org>
Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: [PATCH v3 1/3] dt-bindings: i2c-gpio: Add property i2c-gpio,sda-output-only
Date: Sun, 15 Jan 2023 11:12:30 +0100	[thread overview]
Message-ID: <60e3b33b-360e-94f0-5065-08589cb1cab6@gmail.com> (raw)
In-Reply-To: <3a5545f3-f858-2c80-8bd4-2e0d401a1dc0@gmail.com>

There are slave devices that understand I2C but have read-only
SDA and SCL. Examples are FD650 7-segment LED controller and
its derivatives. Typical board designs don't even have a
pull-up for both pins. Therefore don't enforce open-drain
if SDA and SCL both are unidirectional. This patch makes
i2c-gpio usable with such devices, based on new DT property
i2c-gpio,sda-output-only.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 Documentation/devicetree/bindings/i2c/i2c-gpio.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
index e0d76d5eb..fd84a60d9 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
@@ -33,6 +33,10 @@ properties:
       open drain.
     maxItems: 1
 
+  i2c-gpio,sda-output-only:
+    description: sda as output only
+    type: boolean
+
   i2c-gpio,scl-output-only:
     description: scl as output only
     type: boolean
-- 
2.39.0



  reply	other threads:[~2023-01-15 10:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-15 10:10 [PATCH v3 0/3] i2c: gpio: support write-only sda Heiner Kallweit
2023-01-15 10:12 ` Heiner Kallweit [this message]
2023-01-15 10:15 ` [PATCH v3 2/3] i2c: algo: bit: allow getsda to be NULL Heiner Kallweit
2023-01-16  7:17   ` Peter Rosin
2023-01-16 21:22     ` Heiner Kallweit
2023-01-15 10:18 ` [PATCH v3 3/3] i2c: gpio: support write-only sda Heiner Kallweit
2023-01-16  7:18   ` Peter Rosin
2023-01-16 21:59     ` Heiner Kallweit
2023-01-16 23:15       ` Peter Rosin

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