Re: [PATCH 3/3] dt-bindings: Change the meaning of clock-frequency

[Rob Herring <robh@kernel.org>]

On Fri, Oct 16, 2020 at 02:26:02PM +0800, Billy Tsai wrote:
> Integration of the usage of msg-timing and addr-timing to clock-frequency.
> User can just set it to adjust the peci work efficient.

You're breaking the ABI changing this.

> 
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> ---
>  .../devicetree/bindings/peci/peci-aspeed.yaml | 56 +++++++++----------
>  1 file changed, 28 insertions(+), 28 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/peci/peci-aspeed.yaml b/Documentation/devicetree/bindings/peci/peci-aspeed.yaml
> index 0f5c2993fe9b..7c6c895784af 100644
> --- a/Documentation/devicetree/bindings/peci/peci-aspeed.yaml
> +++ b/Documentation/devicetree/bindings/peci/peci-aspeed.yaml
> @@ -40,31 +40,33 @@ properties:
>      maxItems: 1
>  
>    clock-frequency:
> -    # Operation frequency of PECI controller in units of Hz.
> -    minimum: 187500
> -    maximum: 24000000
> -
> -  msg-timing:
> -    description: |
> -      Message timing negotiation period. This value will determine the period
> -      of message timing negotiation to be issued by PECI controller. The unit
> -      of the programmed value is four times of PECI clock period.
> -    allOf:
> -      - $ref: /schemas/types.yaml#/definitions/uint32
> -      - minimum: 0
> -        maximum: 255
> -        default: 1
> -
> -  addr-timing:
> -    description: |
> -      Address timing negotiation period. This value will determine the period
> -      of address timing negotiation to be issued by PECI controller. The unit
> -      of the programmed value is four times of PECI clock period.
> -    allOf:
> -      - $ref: /schemas/types.yaml#/definitions/uint32
> -      - minimum: 0
> -        maximum: 255
> -        default: 1
> +    # The bit frequency of PECI negotiation stage in units of Hz.
> +    # Driver will calculate the best divisor setting of msg-timing and
> +    # addr-timing to meet the value.

Use 'description' rather than comments.

> +    minimum: 2000
> +    maximum: 2000000
> +
> +  # msg-timing:
> +  #   description: |
> +  #     Message timing negotiation period. This value will determine the period
> +  #     of message timing negotiation to be issued by PECI controller. The unit
> +  #     of the programmed value is four times of PECI clock period.
> +  #   allOf:
> +  #     - $ref: /schemas/types.yaml#/definitions/uint32
> +  #     - minimum: 0
> +  #       maximum: 255
> +  #       default: 1

Why is this commented out?

> +
> +  # addr-timing:
> +  #   description: |
> +  #     Address timing negotiation period. This value will determine the period
> +  #     of address timing negotiation to be issued by PECI controller. The unit
> +  #     of the programmed value is four times of PECI clock period.
> +  #   allOf:
> +  #     - $ref: /schemas/types.yaml#/definitions/uint32
> +  #     - minimum: 0
> +  #       maximum: 255
> +  #       default: 1
>  
>    rd-sampling-point:
>      description: |
> @@ -114,9 +116,7 @@ examples:
>              interrupts = <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>;
>              clocks = <&syscon ASPEED_CLK_GATE_REF0CLK>;
>              resets = <&syscon ASPEED_RESET_PECI>;
> -            clock-frequency = <24000000>;
> -            msg-timing = <1>;
> -            addr-timing = <1>;
> +            clock-frequency = <2000000>;
>              rd-sampling-point = <8>;
>              cmd-timeout-ms = <1000>;
>          };
> -- 
> 2.17.1
> 

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