linux-kernel - Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver bindings

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Date:   Wed, 14 Dec 2022 10:10:57 -0600
From:   Rob Herring <robh@...nel.org>
To:     Fabrizio Castro <fabrizio.castro.jz@...esas.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Sebastian Reichel <sre@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Lee Jones <lee@...nel.org>, linux-gpio@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        linux-renesas-soc@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo@...ndi.org>
Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
 bindings

On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
> Add dt-bindings document for the RZ/V2M PWC GPIO driver.

Bindings are for h/w blocks/devices, not a specific driver.

> 
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> ---
>  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> new file mode 100644
> index 000000000000..ecc034d53259
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/renesas,rzv2m-pwc-gpio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
> +
> +description: |+
> +  The PWC IP found in the RZ/V2M family of chips comes with General-Purpose
> +  Output pins, alongside the below functions
> +    - external power supply on/off sequence generation
> +    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
> +    - key input signals processing
> +  This node uses syscon to map the register used to control the GPIOs
> +  (the register map is retrieved from the parent dt-node), and the node should
> +  be represented as a sub node of a "syscon", "simple-mfd" node.
> +
> +maintainers:
> +  - Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
> +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
> +      - const: renesas,rzv2m-pwc-gpio
> +
> +  offset:

Too generic of a name. We want any given property name (globally) to 
have 1 type. With the below comment, this should be replaced with 'reg' 
instead if you have child nodes.

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Offset in the register map for controlling the GPIOs (in bytes).
> +
> +  regmap:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description: Phandle to the register map node.

Looks like GPIO is a sub-function of some other block. Define the 
binding for that entire block. GPIO can be either either a function of 
that node (just add GPIO provider properties) or you can have GPIO child 
nodes. Depends on what the entire block looks like to decide. Do you 
have multiple instances of the GPIO block would be one reason to have 
child nodes.

> +
> +  gpio-controller: true
> +
> +  '#gpio-cells':
> +    const: 2
> +
> +required:
> +  - compatible
> +  - regmap
> +  - offset
> +  - gpio-controller
> +  - '#gpio-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    gpio {
> +            compatible = "renesas,r9a09g011-pwc-gpio",
> +                         "renesas,rzv2m-pwc-gpio";
> +            regmap = <&regmapnode>;
> +            offset = <0x80>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +    };
> -- 
> 2.34.1
> 
>