linux-kernel - Re: [PATCH v4 2/5] dt-bindings: i2c: Add hpe,gxp-i2c

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Message-ID: <20230125211811.GA2902717-robh@kernel.org>
Date:   Wed, 25 Jan 2023 15:18:11 -0600
From:   Rob Herring <robh@...nel.org>
To:     nick.hawkins@....com
Cc:     verdun@....com, krzysztof.kozlowski+dt@...aro.org,
        linux@...linux.org.uk, linux-i2c@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, joel@....id.au
Subject: Re: [PATCH v4 2/5] dt-bindings: i2c: Add hpe,gxp-i2c

On Wed, Jan 25, 2023 at 12:44:35PM -0600, nick.hawkins@....com wrote:
> From: Nick Hawkins <nick.hawkins@....com>
> 
> Document compatibility string to support I2C controller
> in GXP.
> 
> Signed-off-by: Nick Hawkins <nick.hawkins@....com>
> 
> ---
> v4:
>  *Provide even greater description with the use
>   of Phandle
>  *Reorder properties so they match the required
>   order
> v3:
>  *Provide better description with use of Phandle
> v2:
>  *Removed uneccessary size-cells and address-cells
>  *Removed phandle from hpe,sysreg-phandle
>  *Changed hpe,i2c-max-bus-freq to clock-frequency
> ---
>  .../devicetree/bindings/i2c/hpe,gxp-i2c.yaml  | 59 +++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/hpe,gxp-i2c.yaml
> 
> diff --git a/Documentation/devicetree/bindings/i2c/hpe,gxp-i2c.yaml b/Documentation/devicetree/bindings/i2c/hpe,gxp-i2c.yaml
> new file mode 100644
> index 000000000000..6604dcd47251
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/hpe,gxp-i2c.yaml
> @@ -0,0 +1,59 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/i2c/hpe,gxp-i2c.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: HPE GXP SoC I2C Controller
> +
> +maintainers:
> +  - Nick Hawkins <nick.hawkins@....com>
> +
> +allOf:
> +  - $ref: /schemas/i2c/i2c-controller.yaml#
> +
> +properties:
> +  compatible:
> +    const: hpe,gxp-i2c
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clock-frequency:
> +    default: 100000
> +
> +  hpe,sysreg:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Phandle to the global status and enable interrupt registers shared
> +      between each I2C engine controller instance. It enables the I2C
> +      engine controller to act as both a master or slave by being able to
> +      arm and respond to interrupts from its engine. Each bit in the
> +      registers represent the respective bit position.

Each bit represents the bit position?

AIUI, each I2C instance has a bit in it needs to control. How does the 
driver know what instance (and therefore the correct bit)? Typically you 
would have a 2nd cell here with that information.

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    i2c@...0 {
> +        compatible = "hpe,gxp-i2c";
> +        reg = <0x2500 0x70>;
> +        interrupts = <9>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        hpe,sysreg = <&sysreg_system_controller>;
> +        clock-frequency = <10000>;
> +
> +        eeprom@50 {
> +            compatible = "atmel,24c128";
> +            reg = <0x50>;
> +        };
> +    };
> -- 
> 2.17.1
>