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

From: Rob Herring
Date: Tue May 18 2021 - 22:11:23 EST

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On Tue, May 18, 2021 at 8:39 PM Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxx>
> > Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> > ---
> > .../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@xxxxxxxxxx>
> > +
> > +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@xxxxxxxxxx>
> > +
> > +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.

I take this as like any MFD. If i2c mux is one of the functions, we'll
have a child node for it. In that case, that device's binding will
define the 'i2c-mux' node and then reference this schema. The fact
that this mentions other nodes being I2C devices is not important and
a somewhat confusing detail. I considered just removing as I don't
think the paragraph is all that useful, but I try not to delete too
much from existing bindings.

Rob

Next message: Rik van Riel: "Re: [PATCH] mm: move idle swap cache pages to the tail of LRU after COW"
Previous message: YueHaibing: "[PATCH net-next] ethtool: stats: Fix a copy-paste error"
In reply to: Laurent Pinchart: "Re: [PATCH 4/6] dt-bindings: i2c: Convert i2c-mux bindings to DT schema"
Next in thread: Rob Herring: "[PATCH 5/6] dt-bindings: i2c: i2c-mux-pca954x: Convert to DT schema"
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