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# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/i2c/i2c-mux-gpmux.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: General Purpose I2C Bus Mux
maintainers:
- Peter Rosin <peda@axentia.se>
description: |+
This binding describes an I2C bus multiplexer that uses a mux controller
from the mux subsystem to route the I2C signals.
.-----. .-----.
| dev | | dev |
.------------. '-----' '-----'
| SoC | | |
| | .--------+--------'
| .------. | .------+ child bus A, on MUX value set to 0
| | I2C |-|--| Mux |
| '------' | '--+---+ child bus B, on MUX value set to 1
| .------. | | '----------+--------+--------.
| | MUX- | | | | | |
| | Ctrl |-|-----+ .-----. .-----. .-----.
| '------' | | dev | | dev | | dev |
'------------' '-----' '-----' '-----'
allOf:
- $ref: /schemas/i2c/i2c-mux.yaml#
properties:
compatible:
const: i2c-mux
i2c-parent:
$ref: /schemas/types.yaml#/definitions/phandle
description:
The phandle of the I2C bus that this multiplexer's master-side port is
connected to.
mux-controls:
maxItems: 1
description:
The mux-controller states are the I2C sub-bus numbers.
mux-locked:
type: boolean
description: |
Explicitly allow unrelated I2C transactions on the parent I2C adapter at
these times:
- during setup of the multiplexer
- between setup of the multiplexer and the child bus I2C transaction
- between the child bus I2C transaction and releasing of the multiplexer
- during releasing of the multiplexer
However, I2C transactions to devices behind all I2C multiplexers connected
to the same parent adapter that this multiplexer is connected to are blocked
for the full duration of the complete multiplexed I2C transaction (i.e.
including the times covered by the above list).
If mux-locked is not present, the multiplexer is assumed to be parent-locked.
This means that no unrelated I2C transactions are allowed on the parent I2C
adapter for the complete multiplexed I2C transaction.
The properties of mux-locked and parent-locked multiplexers are discussed
in more detail in Documentation/i2c/i2c-topology.rst.
required:
- compatible
- i2c-parent
- mux-controls
unevaluatedProperties: false
examples:
- |
#include <dt-bindings/gpio/gpio.h>
mux: mux-controller {
compatible = "gpio-mux";
#mux-control-cells = <0>;
mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
<&pioA 1 GPIO_ACTIVE_HIGH>;
};
i2c-mux {
compatible = "i2c-mux";
mux-locked;
i2c-parent = <&i2c1>;
mux-controls = <&mux>;
#address-cells = <1>;
#size-cells = <0>;
i2c@1 {
reg = <1>;
#address-cells = <1>;
#size-cells = <0>;
gpio@20 {
compatible = "nxp,pca9555";
gpio-controller;
#gpio-cells = <2>;
reg = <0x20>;
};
};
i2c@3 {
reg = <3>;
#address-cells = <1>;
#size-cells = <0>;
gpio@20 {
compatible = "nxp,pca9555";
gpio-controller;
#gpio-cells = <2>;
reg = <0x20>;
};
};
};
...
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