acd7ecc9ed
Some Realtek switches have been designed with I2C busses that share a single SCL line. The clock line is used for 2 or more busses. This cannot be used with the standard i2c-gpio driver that relies on distinct SDA and SCL pairs. Provide a derived i2c-gpio-shared driver that can be used instead. This driver can handle up to 4 busses with only a single clock line. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Link: https://github.com/openwrt/openwrt/pull/18737 Signed-off-by: Robert Marko <robimarko@gmail.com>
51 lines
No EOL
1.2 KiB
YAML
51 lines
No EOL
1.2 KiB
YAML
# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/i2c/i2c-gpio-shared.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: mulitple GPIO bitbanged I2C busses with shared SCL
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maintainers:
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- Markus Stockhausen <markus.stockhausen@gmx.de>
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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-shared
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scl-gpios:
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description:
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gpio used for the shared 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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examples:
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- |
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#include <dt-bindings/gpio/gpio.h>
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i2c-gpio-shared {
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compatible = "i2c-gpio-shared";
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scl-gpios = <&gpio1 31 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
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#address-cells = <1>;
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#size-cells = <0>;
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i2c0: i2c@0 {
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sda-gpios = <&gpio1 6 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
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i2c-gpio,delay-us = <2>;
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};
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i2c1: i2c@1 {
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sda-gpios = <&gpio1 7 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
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i2c-gpio,delay-us = <2>;
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};
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};
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required:
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- compatible
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- scl-gpios |