Re: [PATCH 2/2] dt-bindings: i2c: cadence: Document `cdns,fifo-depth` property

[Rob Herring <robh@kernel.org>]

On Sun, Feb 05, 2023 at 03:02:08PM -0800, Lars-Peter Clausen wrote:
> The depth of the FIFO of the Cadence I2C controller IP is a synthesis
> configuration parameter. Different instances of the IP can have different
> values. For correct operation software needs to be aware of the size of the
> FIFO.
> 
> Add the documentation for the devicetree property that describes the FIFO
> depth of the IP core.
> 
> The default value of 16 is for backwards compatibility reasons with
> existing hardware descriptions where this property is not specified and
> software has assumed that the FIFO depth is 16.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> ---
>  Documentation/devicetree/bindings/i2c/cdns,i2c-r1p10.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/cdns,i2c-r1p10.yaml b/Documentation/devicetree/bindings/i2c/cdns,i2c-r1p10.yaml
> index 2e95cda7262a..3daa2fa73257 100644
> --- a/Documentation/devicetree/bindings/i2c/cdns,i2c-r1p10.yaml
> +++ b/Documentation/devicetree/bindings/i2c/cdns,i2c-r1p10.yaml
> @@ -38,6 +38,12 @@ properties:
>      description: |
>        Input clock name.
>  
> +  cdns,fifo-depth:

We already have:

fifo-size
rx-fifo-size
tx-fifo-size
fifo-depth
tx-fifo-depth
rx-fifo-depth

And we have cdns,fifo-depth too (among other vendor specific ones), but 
pick a non-vendor specific one.


> +    description:
> +      Size of the data FIFO in words.

What's the word size? Use bytes.

> +    $ref: "/schemas/types.yaml#/definitions/uint32"
> +    default: 16
> +
>  required:
>    - compatible
>    - reg
> @@ -57,4 +63,6 @@ examples:
>          clock-frequency = <400000>;
>          #address-cells = <1>;
>          #size-cells = <0>;
> +
> +        cdns,fifo-depth = <8>;
>      };
> -- 
> 2.30.2
>