Re: [PATCH v4 09/19] dt-bindings: serial: samsung: Make samsung,uart-fifosize required property

[Rob Herring <robh@kernel.org>]

On Mon, Nov 20, 2023 at 09:20:27PM +0000, Peter Griffin wrote:
> Specifying samsung,uart-fifosize in both DT and driver static data is error
> prone and relies on driver probe order and dt aliases to be correct.
> 
> Additionally on many Exynos platforms these are (USI) universal serial
> interfaces which can be uart, spi or i2c, so it can change per board.
> 
> For google,gs101-uart and exynosautov9-uart make samsung,uart-fifosize a
> required property. For these platforms fifosize now *only* comes from DT.
> 
> It is hoped other Exynos platforms will also switch over time.

Then allow the property on them.

> 
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---
>  .../bindings/serial/samsung_uart.yaml           | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/serial/samsung_uart.yaml b/Documentation/devicetree/bindings/serial/samsung_uart.yaml
> index ccc3626779d9..22a1edadc4fe 100644
> --- a/Documentation/devicetree/bindings/serial/samsung_uart.yaml
> +++ b/Documentation/devicetree/bindings/serial/samsung_uart.yaml
> @@ -133,6 +133,23 @@ allOf:
>              - const: uart
>              - const: clk_uart_baud0
>  
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - google,gs101-uart
> +              - samsung,exynosautov9-uart
> +    then:
> +      properties:
> +        samsung,uart-fifosize:
> +          description: The fifo size supported by the UART channel.
> +          $ref: /schemas/types.yaml#/definitions/uint32
> +          enum: [16, 64, 256]

We already have 'fifo-size' in several drivers. Use that. Please move 
its type/description definitions to serial.yaml and make drivers just do 
'fifo-size: true' if they use it.

> +
> +      required:
> +       - samsung,uart-fifosize

A new required property is an ABI break. Please explain why that is okay 
in the commit message.

Rob