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[2a01:c22:7346:8100:11fa:3b53:e36a:9e73]) by smtp.googlemail.com with ESMTPSA id e20-20020a170906249400b0084d4cb00f0csm10813009ejb.99.2023.01.17.12.39.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Jan 2023 12:39:47 -0800 (PST) Message-ID: Date: Tue, 17 Jan 2023 21:36:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: [PATCH v4 1/3] dt-bindings: i2c-gpio: Add properties for dealing with write-only SDA/SCL w/o pullup Content-Language: en-US From: Heiner Kallweit To: Rob Herring , Krzysztof Kozlowski , Wolfram Sang , Peter Rosin Cc: "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" References: <57666b4f-4c12-7feb-caf1-5bd38908bfc7@gmail.com> In-Reply-To: <57666b4f-4c12-7feb-caf1-5bd38908bfc7@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 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 add properties for not using open-drain. For write-only SCL we have a property already, add one for write-only SDA. Signed-off-by: Heiner Kallweit --- v4: - add no-pullup properties --- .../devicetree/bindings/i2c/i2c-gpio.yaml | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml index e0d76d5eb..67898cc52 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 @@ -63,6 +67,18 @@ properties: GPIO line used for SCL into open drain mode, and that something is not the GPIO chip. It is essentially an inconsistency flag. + i2c-gpio,sda-has-no-pullup: + type: boolean + description: sda is used in a non-compliant way and has no pull-up. + Therefore disable open-drain. This property is mutually-exclusive + with i2c-gpio,sda-open-drain. + + i2c-gpio,scl-has-no-pullup: + type: boolean + description: scl is used in a non-compliant way and has no pull-up. + Therefore disable open-drain. This property is mutually-exclusive + with i2c-gpio,scl-open-drain. + required: - compatible - sda-gpios -- 2.39.0