Re: [PATCH v2 2/4] dt-bindings: serial: uartlite: Add properties for synthesis-time parameters

[Rob Herring <robh@kernel.org>]

On Tue, Jul 27, 2021 at 06:17:38PM -0400, Sean Anderson wrote:
> The uartlite device is a "soft" device. Many parameters, such as baud
> rate, data bits, and the presence of a parity bit are configured before
> synthesis and may not be changed (or discovered) at runtime. However, we
> must know what these settings are in order to properly calculate the
> uart timeout (and to inform the user about the actual baud of the uart).
> 
> These properties are present for out-of-tree bindings generated by
> Xilinx's tools. However, they are also (mostly) present in in-tree
> bindings. I chose current-speed over xlnx,baudrate primarily because it
> seemed to be used by more existing bindings. Although these properties
> are marked as "required", note that only current-speed is required by
> the driver itself. Hopefully, this will allow for an easier transition.
> 
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> ---
> 
> (no changes since v1)
> 
>  .../bindings/serial/xlnx,opb-uartlite.yaml    | 39 +++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml b/Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml
> index 4ef29784ae97..28859e70e60f 100644
> --- a/Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml
> +++ b/Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml
> @@ -32,13 +32,49 @@ properties:
>    clock-names:
>      const: s_axi_aclk
>  
> +  current-speed:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      The fixed baud rate that the device was configured for.
> +
> +  xlnx,data-bits:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [5, 6, 7, 8]
> +    default: 8

default with required doesn't make sense as 'default' what value is 
assumed in the property isn't present.

> +    description:
> +      The fixed number of data bits that the device was configured for.
> +
> +  xlnx,use-parity:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 1]
> +    default: 0
> +    description:
> +      Whether parity checking was enabled when the device was configured.
> +
> +  xlnx,odd-parity:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 1]
> +    description:
> +      Whether odd parity was configured.
> +
>  required:
>    - compatible
>    - reg
>    - interrupts
> +  - current-speed
> +  - xlnx,data-bits
> +  - xlnx,use-parity
>  
>  allOf:
>    - $ref: /schemas/serial.yaml#
> +  - if:
> +      properties:
> +        xlnx,use-parity:
> +          contains:
> +            const: 1
> +    then:
> +      required:
> +        - xlnx,odd-parity
>  
>  additionalProperties: true
>  
> @@ -49,5 +85,8 @@ examples:
>          reg = <0x800c0000 0x10000>;
>          interrupts = <0x0 0x6e 0x1>;
>          port-number = <0>;
> +        current-speed = <115200>;
> +        xlnx,data-bits = <8>;
> +        xlnx,use-parity = <0>;
>        };
>  ...
> -- 
> 2.25.1
> 
>