Re: [PATCH v2 1/2] dt-bindings: gpio: add gpio-line-mux controller

[Rob Herring <robh@kernel.org>]

On Sun, Oct 26, 2025 at 11:17:53PM +0000, Jonas Jelonek wrote:
> Add dt-schema for a gpio-line-mux controller which exposes virtual
> GPIOs for a shared GPIO controlled by a multiplexer, e.g. a gpio-mux.
> 
> The gpio-line-mux controller is a gpio-controller, thus has mostly the
> same semantics. However, it requires a mux-control to be specified upon
> which it will operate.
> 
> Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
> ---
>  .../bindings/gpio/gpio-line-mux.yaml          | 108 ++++++++++++++++++
>  .../devicetree/bindings/mux/gpio-mux.yaml     |  30 +++++
>  2 files changed, 138 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-line-mux.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-line-mux.yaml b/Documentation/devicetree/bindings/gpio/gpio-line-mux.yaml
> new file mode 100644
> index 000000000000..4c907a35eb4d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-line-mux.yaml
> @@ -0,0 +1,108 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/gpio-line-mux.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: GPIO line mux
> +
> +maintainers:
> +  - Jonas Jelonek <jelonek.jonas@gmail.com>
> +
> +description:

You need '>' or '|' to preserve formatting here.

> +  A GPIO controller to provide virtual GPIOs for a 1-to-many mapping backed by
> +  a single shared GPIO and a multiplexer. A simple illustrated example is
> +
> +            +----- A
> +    IN/OUT /
> +    <-----o------- B
> +        / |\
> +        | | +----- C
> +        | |  \
> +        | |   +--- D
> +        | |
> +       M1 M0
> +
> +    MUX CONTROL
> +
> +     M1 M0   IN/OUT
> +      0  0   A
> +      0  1   B
> +      1  0   C
> +      1  1   D
> +
> +  This can be used in case a real GPIO is connected to multiple inputs/outputs
> +  and controlled by a multiplexer, and another subsystem/driver does not work
> +  directly with the multiplexer subsystem.
> +
> +properties:
> +  compatible:
> +    const: gpio-line-mux
> +
> +  gpio-controller: true
> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  gpio-line-mux-states:
> +    description: Mux states corresponding to the virtual GPIOs.
> +    minItems: 1
> +    items:
> +      type: string
> +
> +  gpio-line-names: true
> +
> +  mux-controls:
> +    maxItems: 1
> +    $ref: /schemas/mux/mux-controller.yaml#
> +    description:
> +      Phandle to the multiplexer to control access to the GPIOs.
> +
> +  ngpios: false
> +
> +  shared-gpio:

'-gpio' is deprecated. Use '-gpios'.

> +    description:
> +      GPIO which is the '1' in 1-to-many and is shared by the virtual GPIOs
> +      and controlled via the mux.
> +
> +required:
> +  - compatible
> +  - gpio-controller
> +  - gpio-line-mux-states
> +  - mux-controls
> +  - shared-gpio
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/mux/mux.h>
> +
> +    sfp_gpio_mux: gpio-mux {
> +        compatible = "gpio-mux";
> +        mux-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>,
> +                    <&gpio0 1 GPIO_ACTIVE_HIGH>;
> +        #mux-control-cells = <0>;
> +        idle-state = <MUX_IDLE_AS_IS>;
> +    };
> +
> +    sfp1_gpio: sfp-gpio-1 {
> +        compatible = "gpio-line-mux";
> +        gpio-controller;
> +        #gpio-cells = <2>;
> +
> +        mux-controls = <&sfp_gpio_mux>;
> +        shared-gpio = <&gpio0 2 GPIO_ACTIVE_HIGH>;
> +
> +        gpio-line-names = "SFP1_LOS", "SFP1_MOD_ABS", "SFP1_TX_FAULT";
> +        gpio-line-mux-states = <0>, <1>, <3>;
> +    };
> +
> +    sfp1: sfp-p1 {
> +        compatible = "sff,sfp";
> +
> +        los-gpios = <&sfp1_gpio 0 GPIO_ACTIVE_HIGH>;
> +        mod-def0-gpios = <&sfp1_gpio 1 GPIO_ACTIVE_LOW>;
> +        tx-fault-gpios = <&sfp1_gpio 2 GPIO_ACTIVE_HIGH>;
> +    };
> diff --git a/Documentation/devicetree/bindings/mux/gpio-mux.yaml b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
> index ef7e33ec85d4..57eb1e9ef4cf 100644
> --- a/Documentation/devicetree/bindings/mux/gpio-mux.yaml
> +++ b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
> @@ -100,4 +100,34 @@ examples:
>              };
>          };
>      };
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    sfp_mux: mux-controller {
> +        compatible = "gpio-mux";
> +        #mux-control-cells = <0>;
> +
> +        mux-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>,
> +                    <&gpio0 1 GPIO_ACTIVE_HIGH>;
> +    };
> +
> +    sfp_gpio: sfp-gpio-1 {
> +        compatible = "gpio-line-mux";
> +        gpio-controller;
> +        #gpio-cells = <2>;
> +
> +        mux-controls = <&sfp_mux>;
> +        shared-gpio = <&gpio0 2 GPIO_ACTIVE_HIGH>;
> +
> +        gpio-line-names = "SFP_LOS", "SFP_MOD_ABS", "SFP_TX_F";
> +        gpio-line-mux-states = <0>, <1>, <2>;
> +    };
> +
> +    sfp0: sfp-p0 {
> +        compatible = "sff,sfp";
> +
> +        los-gpios = <&sfp_gpio 0 GPIO_ACTIVE_HIGH>;
> +        mod-def0-gpios = <&sfp_gpio 1 GPIO_ACTIVE_LOW>;
> +        tx-fault-gpios = <&sfp_gpio 2 GPIO_ACTIVE_HIGH>;

Drop. We don't need the same example twice.

Rob