Re: [PATCH v4 3/5] dt-bindings: media: add cat24c208 bindings

[Rob Herring <robh@kernel.org>]

On Fri, Nov 11, 2022 at 02:29:04PM +0100, Erling Ljunggren wrote:
> Add devicetree bindings for new cat24c208 EDID EEPROM driver.
> 
> Signed-off-by: Erling Ljunggren <hljunggr@cisco.com>
> ---
>  .../bindings/media/i2c/onnn,cat24c208.yaml    | 46 +++++++++++++++++++
>  1 file changed, 46 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/onnn,cat24c208.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/onnn,cat24c208.yaml b/Documentation/devicetree/bindings/media/i2c/onnn,cat24c208.yaml
> new file mode 100644
> index 000000000000..492eecb3ab7c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/onnn,cat24c208.yaml
> @@ -0,0 +1,46 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/onnn,cat24c208.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ON Semiconductor CAT24C208 EDID EEPROM driver
> +
> +maintainers:
> +  - Hans Verkuil <hverkuil-cisco@xs4all.nl>
> +
> +description: |
> +  CAT24C208 is a dual port i2c EEPROM designed for EDID storage.
> +
> +properties:
> +  compatible:
> +    const: onnn,cat24c208
> +
> +  reg:
> +    maxItems: 1
> +
> +  input-connector:
> +    description: |
> +      Phandle to the video input connector, used to find
> +      the HPD gpio and the connector label, both optional.
> +    $ref: /schemas/types.yaml#/definitions/phandle

The binding and driver feel the wrong way around to me. It seems 
like you should have a driver for the connector and it needs HPD GPIO, 
label, and EEPROM. The driver instead looks mostly like an EEPROM driver 
that hooks into a few connector properties.

Reading the datasheet, I don't see anything special about accessing the 
EEPROM from the host (DSP) side. Wouldn't the default at24 driver work? 
It exposes regmap and nvmem.

Rob