[PATCH 1/2] dt-bindings: serial: stm32: add fifo threshold configuration

[Rob Herring]

On Tue, Apr 06, 2021 at 09:21:21AM +0200, Erwan Le Ray wrote:
> Add two optional DT properties, to configure RX and TX fifo threshold:
> - st,rx-fifo-threshold-bytes
> - st,tx-fifo-threshold-bytes
> 
> This patch depends on patch ("dt-bindings: serial: Add rx-tx-swap to stm32-usart").
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
> Signed-off-by: Erwan Le Ray <erwan.leray at foss.st.com>
> 
> diff --git a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
> index c69f8464cdf3..e163449bf39e 100644
> --- a/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
> +++ b/Documentation/devicetree/bindings/serial/st,stm32-uart.yaml
> @@ -65,6 +65,22 @@ properties:
>    linux,rs485-enabled-at-boot-time: true
>    rs485-rx-during-tx: true
>  
> +  st,rx-fifo-threshold-bytes:
> +    description:
> +      RX FIFO threshold configuration in bytes.
> +      If value is set to 1, RX FIFO threshold is disabled.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [1, 2, 4, 8, 12, 14, 16]
> +    default: 8
> +
> +  st,tx-fifo-threshold-bytes:
> +    description:
> +      TX FIFO threshold configuration in bytes.
> +      If value is set to 1, TX FIFO threshold is disabled.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [1, 2, 4, 8, 12, 14, 16]
> +    default: 8

We already have 'tx-threshold' for 8250, so reuse that and add 
'rx-threshold'.

Rob