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dt-bindings: i2c: i2c-mux-pinctrl: Convert to json-schema 

Convert the pinctrl-based I2C mux bindings from the free-form text
format to json-schema.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211217165658.2650677-2-thierry.reding@gmail.com
This commit is contained in:
Thierry Reding 2021-12-17 17:56:56 +01:00 committed by Rob Herring
parent f10a9b722f
commit 8b82b8416f
2 changed files with 103 additions and 93 deletions
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93
Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
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Pinctrl-based I2C Bus Mux
This binding describes an I2C bus multiplexer that uses pin multiplexing to
route the I2C signals, and represents the pin multiplexing configuration
using the pinctrl device tree bindings.
+-----+ +-----+
| dev | | dev |
+------------------------+ +-----+ +-----+
| SoC | | |
| /----|------+--------+
| +---+ +------+ | child bus A, on first set of pins
| |I2C|---|Pinmux| |
| +---+ +------+ | child bus B, on second set of pins
| \----|------+--------+--------+
| | | | |
+------------------------+ +-----+ +-----+ +-----+
| dev | | dev | | dev |
+-----+ +-----+ +-----+
Required properties:
- compatible: i2c-mux-pinctrl
- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
port is connected to.
Also required are:
* Standard pinctrl properties that specify the pin mux state for each child
bus. See ../pinctrl/pinctrl-bindings.txt.
* Standard I2C mux properties. See i2c-mux.yaml in this directory.
* I2C child bus nodes. See i2c-mux.yaml in this directory.
For each named state defined in the pinctrl-names property, an I2C child bus
will be created. I2C child bus numbers are assigned based on the index into
the pinctrl-names property.
The only exception is that no bus will be created for a state named "idle". If
such a state is defined, it must be the last entry in pinctrl-names. For
example:
pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
Whenever an access is made to a device on a child bus, the relevant pinctrl
state will be programmed into hardware.
If an idle state is defined, whenever an access is not being made to a device
on a child bus, the idle pinctrl state will be programmed into hardware.
If an idle state is not defined, the most recently used pinctrl state will be
left programmed into hardware whenever no access is being made of a device on
a child bus.
Example:
i2cmux {
compatible = "i2c-mux-pinctrl";
#address-cells = <1>;
#size-cells = <0>;
i2c-parent = <&i2c1>;
pinctrl-names = "ddc", "pta", "idle";
pinctrl-0 = <&state_i2cmux_ddc>;
pinctrl-1 = <&state_i2cmux_pta>;
pinctrl-2 = <&state_i2cmux_idle>;
i2c@0 {
reg = <0>;
#address-cells = <1>;
#size-cells = <0>;
eeprom {
compatible = "eeprom";
reg = <0x50>;
};
};
i2c@1 {
reg = <1>;
#address-cells = <1>;
#size-cells = <0>;
eeprom {
compatible = "eeprom";
reg = <0x50>;
};
};
};

103
Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.yaml Normal file
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# SPDX-License-Identifier: GPL-2.0-only
%YAML 1.2
---
$id: http://devicetree.org/schemas/i2c/i2c-mux-pinctrl.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Pinctrl-based I2C Bus Mux
maintainers:
- Wolfram Sang <wsa@kernel.org>
description: |
This binding describes an I2C bus multiplexer that uses pin multiplexing to route the I2C
signals, and represents the pin multiplexing configuration using the pinctrl device tree
bindings.
+-----+ +-----+
| dev | | dev |
+------------------------+ +-----+ +-----+
| SoC | | |
| /----|------+--------+
| +---+ +------+ | child bus A, on first set of pins
| |I2C|---|Pinmux| |
| +---+ +------+ | child bus B, on second set of pins
| \----|------+--------+--------+
| | | | |
+------------------------+ +-----+ +-----+ +-----+
| dev | | dev | | dev |
+-----+ +-----+ +-----+
For each named state defined in the pinctrl-names property, an I2C child bus will be created.
I2C child bus numbers are assigned based on the index into the pinctrl-names property.
The only exception is that no bus will be created for a state named "idle". If such a state is
defined, it must be the last entry in pinctrl-names. For example:
pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
Whenever an access is made to a device on a child bus, the relevant pinctrl state will be
programmed into hardware.
If an idle state is defined, whenever an access is not being made to a device on a child bus,
the idle pinctrl state will be programmed into hardware.
If an idle state is not defined, the most recently used pinctrl state will be left programmed
into hardware whenever no access is being made of a device on a child bus.
properties:
compatible:
const: i2c-mux-pinctrl
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.
allOf:
- $ref: i2c-mux.yaml
unevaluatedProperties: false
required:
- compatible
- i2c-parent
examples:
- |
i2cmux {
compatible = "i2c-mux-pinctrl";
#address-cells = <1>;
#size-cells = <0>;
i2c-parent = <&i2c1>;
pinctrl-names = "ddc", "pta", "idle";
pinctrl-0 = <&state_i2cmux_ddc>;
pinctrl-1 = <&state_i2cmux_pta>;
pinctrl-2 = <&state_i2cmux_idle>;
i2c@0 {
reg = <0>;
#address-cells = <1>;
#size-cells = <0>;
eeprom@50 {
compatible = "atmel,24c02";
reg = <0x50>;
};
};
i2c@1 {
reg = <1>;
#address-cells = <1>;
#size-cells = <0>;
eeprom@50 {
compatible = "atmel,24c02";
reg = <0x50>;
};
};
};