Re: [PATCH] regulator: dt-bindings: rpi-panel: Split 7" Raspberry Pi 720x1280 v2 binding

[Conor Dooley <conor@kernel.org>]

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On Thu, Sep 04, 2025 at 09:58:26PM +0200, Marek Vasut wrote:
> The 5" and 7" Raspberry Pi 720x1280 Display 2 MCU is a bit more
> complex than the original Display 1 ATTINY88 and the binding is
> also a bit more demanding. Split the binding into separate file
> and fill in required gpio-controller, #gpio-cells and #pwm-cells
> which must be present for the V2 MCU. Include mention of the 5"
> panel in the description of Display 2, as the 5" panel uses the
> same MCU.
> 
> Fixes: 6d09c6e474bd ("regulator: dt-bindings: rpi-panel: Add regulator for 7" Raspberry Pi 720x1280")
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Liam Girdwood <lgirdwood@gmail.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-rpi-kernel@lists.infradead.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
>  ...,7inch-touchscreen-panel-regulator-v2.yaml | 61 +++++++++++++++++++
>  ...ypi,7inch-touchscreen-panel-regulator.yaml |  7 +--
>  2 files changed, 63 insertions(+), 5 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator-v2.yaml
> 
> diff --git a/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator-v2.yaml b/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator-v2.yaml
> new file mode 100644
> index 0000000000000..efc7815a136b4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator-v2.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/regulator/raspberrypi,7inch-touchscreen-panel-regulator-v2.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RaspberryPi 5" and 7" display V2 MCU-based regulator/backlight controller
> +
> +maintainers:
> +  - Marek Vasut <marek.vasut+renesas@mailbox.org>
> +
> +description: |
> +  The RaspberryPi 5" and 7" display 2 has an MCU-based regulator, PWM
> +  backlight and GPIO controller on the PCB, which is used to turn the
> +  display unit on/off and control the backlight.
> +
> +allOf:
> +  - $ref: regulator.yaml#
> +
> +properties:
> +  compatible:
> +    const: raspberrypi,touchscreen-panel-regulator-v2
> +
> +  reg:
> +    maxItems: 1
> +
> +  gpio-controller: true
> +  "#gpio-cells":
> +    const: 2
> +    description:
> +      The first cell is the pin number, and the second cell is used to
> +      specify the gpio polarity (GPIO_ACTIVE_HIGH or GPIO_ACTIVE_LOW).
> +
> +  "#pwm-cells":
> +    const: 3
> +    description: See ../../pwm/pwm.yaml for description of the cell formats.
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - gpio-controller
> +  - "#gpio-cells"
> +  - "#pwm-cells"
> +
> +examples:
> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +      gpio@45 {

ngl, seems strange to classify the device as a regulator in directory
and name, but use gpio as the node name in the example.

Otherwise, this seems fine - if you feel that the hardware is
substantively differentially to what's in the "v1" regulator then
keeping them apart is valid.
Acked-by: Conor Dooley <conor.dooley@microchip.com>

> +        compatible = "raspberrypi,touchscreen-panel-regulator-v2";
> +        reg = <0x45>;
> +        gpio-controller;
> +        #gpio-cells = <2>;
> +        #pwm-cells = <3>;
> +      };
> +    };
> +
> +...
> diff --git a/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator.yaml b/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator.yaml
> index 18944d39d08fc..41678400e63fa 100644
> --- a/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator.yaml
> +++ b/Documentation/devicetree/bindings/regulator/raspberrypi,7inch-touchscreen-panel-regulator.yaml
> @@ -12,17 +12,14 @@ maintainers:
>  description: |
>    The RaspberryPi 7" display has an ATTINY88-based regulator/backlight
>    controller on the PCB, which is used to turn the display unit on/off
> -  and control the backlight. The V2 supports 5" and 7" panels and also
> -  offers PWM backlight control.
> +  and control the backlight.
>  
>  allOf:
>    - $ref: regulator.yaml#
>  
>  properties:
>    compatible:
> -    enum:
> -      - raspberrypi,7inch-touchscreen-panel-regulator
> -      - raspberrypi,touchscreen-panel-regulator-v2
> +    const: raspberrypi,7inch-touchscreen-panel-regulator
>  
>    reg:
>      maxItems: 1
> -- 
> 2.50.1
> 

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