104 lines
3.1 KiB
YAML
104 lines
3.1 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0-only
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/i2c/i2c-mux-pinctrl.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Pinctrl-based I2C Bus Mux
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maintainers:
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- Wolfram Sang <wsa@kernel.org>
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description: |
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This binding describes an I2C bus multiplexer that uses pin multiplexing to route the I2C
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signals, and represents the pin multiplexing configuration using the pinctrl device tree
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bindings.
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+-----+ +-----+
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| dev | | dev |
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+------------------------+ +-----+ +-----+
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| SoC | | |
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| /----|------+--------+
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| +---+ +------+ | child bus A, on first set of pins
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| |I2C|---|Pinmux| |
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| +---+ +------+ | child bus B, on second set of pins
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| \----|------+--------+--------+
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| | | | |
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+------------------------+ +-----+ +-----+ +-----+
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| dev | | dev | | dev |
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+-----+ +-----+ +-----+
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For each named state defined in the pinctrl-names property, an I2C child bus will be created.
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I2C child bus numbers are assigned based on the index into the pinctrl-names property.
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The only exception is that no bus will be created for a state named "idle". If such a state is
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defined, it must be the last entry in pinctrl-names. For example:
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pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
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pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
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pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
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Whenever an access is made to a device on a child bus, the relevant pinctrl state will be
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programmed into hardware.
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If an idle state is defined, whenever an access is not being made to a device on a child bus,
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the idle pinctrl state will be programmed into hardware.
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If an idle state is not defined, the most recently used pinctrl state will be left programmed
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into hardware whenever no access is being made of a device on a child bus.
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properties:
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compatible:
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const: i2c-mux-pinctrl
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i2c-parent:
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$ref: /schemas/types.yaml#/definitions/phandle
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description: The phandle of the I2C bus that this multiplexer's master-side port is connected
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to.
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allOf:
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- $ref: i2c-mux.yaml
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unevaluatedProperties: false
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required:
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- compatible
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- i2c-parent
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examples:
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- |
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i2cmux {
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compatible = "i2c-mux-pinctrl";
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#address-cells = <1>;
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#size-cells = <0>;
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i2c-parent = <&i2c1>;
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pinctrl-names = "ddc", "pta", "idle";
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pinctrl-0 = <&state_i2cmux_ddc>;
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pinctrl-1 = <&state_i2cmux_pta>;
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pinctrl-2 = <&state_i2cmux_idle>;
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i2c@0 {
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reg = <0>;
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#address-cells = <1>;
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#size-cells = <0>;
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eeprom@50 {
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compatible = "atmel,24c02";
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reg = <0x50>;
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};
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};
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i2c@1 {
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reg = <1>;
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#address-cells = <1>;
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#size-cells = <0>;
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eeprom@50 {
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compatible = "atmel,24c02";
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reg = <0x50>;
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};
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};
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};
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