Re: [PATCH 4/6] dt-bindings: i2c: Convert i2c-mux bindings to DT schema

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Rob,

Thank you for the patch.

On Tue, May 18, 2021 at 06:28:56PM -0500, Rob Herring wrote:
> As some of the example I2C devices don't have schemas yet, change them to
> ones that do.
> 
> Cc: Peter Rosin <peda@axentia.se>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
>  .../bindings/i2c/i2c-demux-pinctrl.txt        |   2 +-
>  .../devicetree/bindings/i2c/i2c-mux-gpio.txt  |   4 +-
>  .../devicetree/bindings/i2c/i2c-mux-gpmux.txt |  99 --------------
>  .../bindings/i2c/i2c-mux-gpmux.yaml           | 124 ++++++++++++++++++
>  .../bindings/i2c/i2c-mux-ltc4306.txt          |   4 +-
>  .../bindings/i2c/i2c-mux-pinctrl.txt          |   4 +-
>  .../devicetree/bindings/i2c/i2c-mux-reg.txt   |   4 +-
>  .../devicetree/bindings/i2c/i2c-mux.txt       |  73 -----------
>  .../devicetree/bindings/i2c/i2c-mux.yaml      |  87 ++++++++++++
>  9 files changed, 220 insertions(+), 181 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.txt
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
>  delete mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux.txt
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux.yaml
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
> index 81b5d55086fa..86b2e433a969 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
> @@ -27,7 +27,7 @@ Required properties:
>  - i2c-bus-name: The name of this bus. Also needed as pinctrl-name for the I2C
>  		parents.
>  
> -Furthermore, I2C mux properties and child nodes. See i2c-mux.txt in this
> +Furthermore, I2C mux properties and child nodes. See i2c-mux.yaml in this
>  directory.
>  
>  Example:
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
> index 21da3ecbb370..e00d2b9e957a 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
> @@ -22,8 +22,8 @@ Required properties:
>  - i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
>    port is connected to.
>  - mux-gpios: list of gpios used to control the muxer
> -* Standard I2C mux properties. See i2c-mux.txt in this directory.
> -* I2C child bus nodes. See i2c-mux.txt in this directory.
> +* Standard I2C mux properties. See i2c-mux.yaml in this directory.
> +* I2C child bus nodes. See i2c-mux.yaml in this directory.
>  
>  Optional properties:
>  - idle-state: value to set the muxer to when idle. When no value is
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.txt
> deleted file mode 100644
> index 057083a8ba17..000000000000
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.txt
> +++ /dev/null
> @@ -1,99 +0,0 @@
> -General Purpose I2C Bus Mux
> -
> -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 |
> -    '------------'                  '-----'  '-----'  '-----'
> -
> -Required properties:
> -- compatible: i2c-mux
> -- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
> -  port is connected to.
> -- mux-controls: The phandle of the mux controller to use for operating the
> -  mux.
> -* Standard I2C mux properties. See i2c-mux.txt in this directory.
> -* I2C child bus nodes. See i2c-mux.txt in this directory. The sub-bus number
> -  is also the mux-controller state described in ../mux/mux-controller.yaml
> -
> -Optional properties:
> -- mux-locked: If present, 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.
> -
> -For each i2c child node, an I2C child bus will be created. They will
> -be numbered based on their order in the device tree.
> -
> -Whenever an access is made to a device on a child bus, the value set
> -in the relevant node's reg property will be set as the state in the
> -mux controller.
> -
> -Example:
> -	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>;
> -
> -			ssd1307: oled@3c {
> -				compatible = "solomon,ssd1307fb-i2c";
> -				reg = <0x3c>;
> -				pwms = <&pwm 4 3000>;
> -				reset-gpios = <&gpio2 7 1>;
> -				reset-active-low;
> -			};
> -		};
> -
> -		i2c@3 {
> -			reg = <3>;
> -			#address-cells = <1>;
> -			#size-cells = <0>;
> -
> -			pca9555: pca9555@20 {
> -				compatible = "nxp,pca9555";
> -				gpio-controller;
> -				#gpio-cells = <2>;
> -				reg = <0x20>;
> -			};
> -		};
> -	};
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
> new file mode 100644
> index 000000000000..3e6ea59aea68
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
> @@ -0,0 +1,124 @@
> +# 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>;
> +            };
> +        };
> +    };
> +...
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt
> index 8b1e49cdce3f..29c4550c9782 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt
> @@ -8,8 +8,8 @@ Required Properties:
>  
>    The following required properties are defined externally:
>  
> -  - Standard I2C mux properties. See i2c-mux.txt in this directory.
> -  - I2C child bus nodes. See i2c-mux.txt in this directory.
> +  - Standard I2C mux properties. See i2c-mux.yaml in this directory.
> +  - I2C child bus nodes. See i2c-mux.yaml in this directory.
>  
>  Optional Properties:
>  
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> index 33119a98e144..997a287ed3f6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> @@ -28,9 +28,9 @@ 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.txt in this directory.
> +* Standard I2C mux properties. See i2c-mux.yaml in this directory.
>  
> -* I2C child bus nodes. See i2c-mux.txt 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
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
> index de00d7fc450b..b9d9755e4172 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
> @@ -7,8 +7,8 @@ Required properties:
>  - compatible: i2c-mux-reg
>  - i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
>    port is connected to.
> -* Standard I2C mux properties. See i2c-mux.txt in this directory.
> -* I2C child bus nodes. See i2c-mux.txt in this directory.
> +* Standard I2C mux properties. See i2c-mux.yaml in this directory.
> +* I2C child bus nodes. See i2c-mux.yaml in this directory.
>  
>  Optional properties:
>  - reg: this pair of <offset size> specifies the register to control the mux.
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux.txt b/Documentation/devicetree/bindings/i2c/i2c-mux.txt
> deleted file mode 100644
> index b38f58a1c878..000000000000
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux.txt
> +++ /dev/null
> @@ -1,73 +0,0 @@
> -Common i2c bus multiplexer/switch properties.
> -
> -An i2c bus multiplexer/switch will have several child busses that are
> -numbered uniquely in a device dependent manner.  The nodes for an i2c bus
> -multiplexer/switch will have one child node for each child bus.
> -
> -Optional properties:
> -- #address-cells = <1>;
> -   This property is required if the i2c-mux child node does not exist.
> -
> -- #size-cells = <0>;
> -   This property is required if the i2c-mux child node does not exist.
> -
> -- i2c-mux
> -   For i2c multiplexers/switches that have child nodes that are a mixture
> -   of both i2c child busses and other child nodes, the 'i2c-mux' subnode
> -   can be used for populating the i2c child busses.  If an 'i2c-mux'
> -   subnode is present, only subnodes of this will be considered as i2c
> -   child busses.
> -
> -Required properties for the i2c-mux child node:
> -- #address-cells = <1>;
> -- #size-cells = <0>;
> -
> -Required properties for i2c child bus nodes:
> -- #address-cells = <1>;
> -- #size-cells = <0>;
> -- reg : The sub-bus number.
> -
> -Optional properties for i2c child bus nodes:
> -- Other properties specific to the multiplexer/switch hardware.
> -- Child nodes conforming to i2c bus binding
> -
> -
> -Example :
> -
> -	/*
> -	   An NXP pca9548 8 channel I2C multiplexer at address 0x70
> -	   with two NXP pca8574 GPIO expanders attached, one each to
> -	   ports 3 and 4.
> -	 */
> -
> -	mux@70 {
> -		compatible = "nxp,pca9548";
> -		reg = <0x70>;
> -		#address-cells = <1>;
> -		#size-cells = <0>;
> -
> -		i2c@3 {
> -			#address-cells = <1>;
> -			#size-cells = <0>;
> -			reg = <3>;
> -
> -			gpio1: gpio@38 {
> -				compatible = "nxp,pca8574";
> -				reg = <0x38>;
> -				#gpio-cells = <2>;
> -				gpio-controller;
> -			};
> -		};
> -		i2c@4 {
> -			#address-cells = <1>;
> -			#size-cells = <0>;
> -			reg = <4>;
> -
> -			gpio2: gpio@38 {
> -				compatible = "nxp,pca8574";
> -				reg = <0x38>;
> -				#gpio-cells = <2>;
> -				gpio-controller;
> -			};
> -		};
> -	};
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux.yaml
> new file mode 100644
> index 000000000000..3aa4d84a6610
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux.yaml
> @@ -0,0 +1,87 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/i2c/i2c-mux.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Common i2c bus multiplexer/switch properties.
> +
> +maintainers:
> +  - Peter Rosin <peda@axentia.se>
> +
> +description: |+
> +  An i2c bus multiplexer/switch will have several child busses that are numbered
> +  uniquely in a device dependent manner.  The nodes for an i2c bus
> +  multiplexer/switch will have one child node for each child bus.
> +
> +  For i2c multiplexers/switches that have child nodes that are a mixture of both
> +  i2c child busses and other child nodes, the 'i2c-mux' subnode can be used for
> +  populating the i2c child busses.  If an 'i2c-mux' subnode is present, only
> +  subnodes of this will be considered as i2c child busses.

As I understand this, it means that child nodes corresponding to child
buses can be either direct children of the I2C mux node, or grouped in a
i2c-mux node (the same way we optionally group the 'port' nodes in a
'ports' node). This doesn't seem to be supported by the bindings below.

> +
> +properties:
> +  $nodename:
> +    pattern: '^(i2c-?)?mux'
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  '^i2c@[0-9a-f]+$':
> +    $ref: /schemas/i2c/i2c-controller.yaml
> +    unevaluatedProperties: false
> +
> +    properties:
> +      reg:
> +        description: The mux selector sub-bus number for the child I2C bus.
> +        maxItems: 1
> +
> +additionalProperties: true
> +
> +examples:
> +  - |
> +    /*
> +       An NXP pca9548 8 channel I2C multiplexer at address 0x70
> +       with two NXP pca8574 GPIO expanders attached, one each to
> +       ports 3 and 4.

I'd add the missing * while at it.

> +     */
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        i2c-mux@70 {
> +            compatible = "nxp,pca9548";
> +            reg = <0x70>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            i2c@3 {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                reg = <3>;
> +
> +                gpio@20 {
> +                    compatible = "nxp,pca9555";
> +                    gpio-controller;
> +                    #gpio-cells = <2>;
> +                    reg = <0x20>;
> +                };
> +            };
> +            i2c@4 {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                reg = <4>;
> +
> +                gpio@20 {
> +                    compatible = "nxp,pca9555";
> +                    gpio-controller;
> +                    #gpio-cells = <2>;
> +                    reg = <0x20>;
> +                };
> +            };
> +        };
> +    };
> +...

-- 
Regards,

Laurent Pinchart