Re: [PATCH v3 1/8] dt-bindings: clock: imx8m-clock: support spread spectrum clocking

Krzysztof Kozlowski
2024-11-06T14:23:14Z

On Wed, Nov 06, 2024 at 09:57:57AM +0100, Dario Binacchi wrote:
> The patch adds the DT bindings for enabling and tuning spread spectrum
> clocking generation.

We had long talks about this but nothing of it got reflected in commit
msg. Sorry, I don't remember what I was talking in some particular patch
month ago, so you will get the same questions over and over...

>
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
>
> ---
>
> Changes in v3:
> - Added in v3
> - The dt-bindings have been moved from fsl,imx8m-anatop.yaml to
> imx8m-clock.yaml. The anatop device (fsl,imx8m-anatop.yaml) is
> indeed more or less a syscon, so it represents a memory area
> accessible by ccm (imx8m-clock.yaml) to setup the PLLs.
>
> .../bindings/clock/imx8m-clock.yaml | 46 +++++++++++++++++++
> 1 file changed, 46 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> index c643d4a81478..7920393e518e 100644
> --- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> +++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
> @@ -43,6 +43,40 @@ properties:
> ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-clock.h
> for the full list of i.MX8M clock IDs.
>
> + fsl,ssc-clocks:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + description:
> + Phandles of the PLL with spread spectrum generation hardware capability.
> + minItems: 1
> + maxItems: 4

1. How is it possible that you change spread spectrum of some clocks from
main Clock Controller, while this device is not a consumer of them?
Basically this means that this device does not have these clocks but yet
you claim that it needs to configure spread for them! It's contradictory
to me and nohing got explained in commit msg about it. I am pretty sure
I asked about this alrady.

2. Why is this array flexible in size?

Best regards,
Krzysztof