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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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a00bb94c7b
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 <hkallweit1@gmail.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Wolfram Sang <wsa@kernel.org>
100 lines
2.6 KiB
YAML
100 lines
2.6 KiB
YAML
# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/i2c/i2c-gpio.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: GPIO bitbanged I2C
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maintainers:
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- Wolfram Sang <wsa@kernel.org>
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allOf:
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- $ref: /schemas/i2c/i2c-controller.yaml#
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properties:
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compatible:
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items:
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- const: i2c-gpio
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sda-gpios:
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description:
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gpio used for the sda signal, this should be flagged as
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active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)
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from <dt-bindings/gpio/gpio.h> since the signal is by definition
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open drain.
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maxItems: 1
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scl-gpios:
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description:
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gpio used for the scl signal, this should be flagged as
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active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)
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from <dt-bindings/gpio/gpio.h> since the signal is by definition
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open drain.
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maxItems: 1
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i2c-gpio,sda-output-only:
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description: sda as output only
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type: boolean
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i2c-gpio,scl-output-only:
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description: scl as output only
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type: boolean
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i2c-gpio,delay-us:
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description: delay between GPIO operations (may depend on each platform)
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i2c-gpio,timeout-ms:
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description: timeout to get data
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# Deprecated properties, do not use in new device tree sources:
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gpios:
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minItems: 2
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maxItems: 2
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description: sda and scl gpio, alternative for {sda,scl}-gpios
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i2c-gpio,sda-open-drain:
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type: boolean
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deprecated: true
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description: this means that something outside of our control has put
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the GPIO line used for SDA into open drain mode, and that something is
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not the GPIO chip. It is essentially an inconsistency flag.
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i2c-gpio,scl-open-drain:
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type: boolean
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deprecated: true
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description: this means that something outside of our control has put the
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GPIO line used for SCL into open drain mode, and that something is not
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the GPIO chip. It is essentially an inconsistency flag.
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i2c-gpio,sda-has-no-pullup:
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type: boolean
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description: sda is used in a non-compliant way and has no pull-up.
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Therefore disable open-drain. This property is mutually-exclusive
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with i2c-gpio,sda-open-drain.
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i2c-gpio,scl-has-no-pullup:
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type: boolean
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description: scl is used in a non-compliant way and has no pull-up.
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Therefore disable open-drain. This property is mutually-exclusive
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with i2c-gpio,scl-open-drain.
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dependencies:
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i2c-gpio,sda-has-no-pullup:
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not:
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required:
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- i2c-gpio,sda-open-drain
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i2c-gpio,scl-has-no-pullup:
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not:
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required:
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- i2c-gpio,scl-open-drain
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required:
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- compatible
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- sda-gpios
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- scl-gpios
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unevaluatedProperties: false
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...
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