Re: [PATCH 1/6] dt-bindings: clock: imx8m-anatop: support spread spectrum clocking

On 05/10/2024 10:57, Dario Binacchi wrote:

On Thu, Oct 3, 2024 at 12:46 PM Krzysztof Kozlowski [off-list ref] wrote:

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On 01/10/2024 08:29, Dario Binacchi wrote:

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On Mon, Sep 30, 2024 at 8:45 AM Krzysztof Kozlowski [off-list ref] wrote:

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On 29/09/2024 22:00, Dario Binacchi wrote:

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+  properties:
+    compatible:
+      contains:
+        enum:
+          - fsl,imx8mm-anatop
+
+then:
+  properties:
+    fsl,ssc-clocks:

Nope. Properties must be defined in top-level.

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+      $ref: /schemas/types.yaml#/definitions/phandle-array
+      description:
+        The phandles to the PLLs with spread spectrum clock generation
+        hardware capability.

These should be clocks.

Sorry, but I can't understand what you're asking me.
Could you kindly explain it to me in more detail?

You added new property instead of using existing one for this purpose:
'clocks'.

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Best regards,
Krzysztof

I added this new property specifically for managing spread-spectrum.
Indeed, not all clocks/PLLs
managed by the node/peripheral support spread-spectrum, and the added
properties specify
parameters for enabling and tuning SSC for each individual PLL based
on the index of each list.
If I were to use the 'clocks' property and add a clock to this list
that does not support SSC, IMHO
the pairings would be less clear.

You duplicate property with argument "pairings shall match". Well, I am
not happy with the duplication. Clocks have specific order, thus it is
explicit which one needs tuning. Your other properties can match them as
well, just index from clocks is offset...

Just to check if I understood correctly what you are suggesting before
submitting version 3 of the patch.
Something, for example, like:

clocks = <&clk, IMX8MP_AUDIO_PLL1>,  <&clk, IMX8MP_AUDIO_PLL2>, <&clk
IMX8MP_VIDEO_PLL1>;
fsl,ssc-modfreq-hz = <0, 3517>, <2, 6818>;

Hm, what is 0? If clock index, then no, it's redundant. The first item
in cannot point to other clock.

Also, what exactly are you setting here and why assigned-clock-rates are
not working?

Best regards,
Krzysztof