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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>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: [PATCH v2 1/3] dt-bindings: i2c-gpio: Add property i2c-gpio,sda-output-only
Date: Wed, 27 Apr 2022 21:23:28 +0200	[thread overview]
Message-ID: <e2e30c3b-21db-72d1-1b40-d1f2fbcaaa43@gmail.com> (raw)
In-Reply-To: <3e6c934e-5298-42c5-c346-31b1acaa06ba@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.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- improve commit message
---
 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 fd0402845..25cd1b260 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
-- 
2.35.3




  reply	other threads:[~2022-04-27 19:27 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-27 19:20 [PATCH v2 0/3] i2c: gpio: support write-only sda Heiner Kallweit
2022-04-27 19:23 ` Heiner Kallweit [this message]
2022-05-03 21:11   ` [PATCH v2 1/3] dt-bindings: i2c-gpio: Add property i2c-gpio,sda-output-only Rob Herring
2022-04-27 19:24 ` [PATCH v2 2/3] i2c: algo: bit: allow getsda to be NULL Heiner Kallweit
2022-05-16 19:31   ` Wolfram Sang
2022-08-14 21:06     ` Heiner Kallweit
2022-04-27 19:25 ` [PATCH v2 3/3] i2c: gpio: support write-only sda Heiner Kallweit
2022-05-16 19:37   ` Wolfram Sang

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