Re: [PATCH v2 04/16] dt-bindings: clock: at91: Allow referencing main rc oscillator in DT

Alexander Dahl
2025-02-11T07:26:17Z

Hello Krzysztof,

Am Mon, Feb 10, 2025 at 06:07:10PM +0100 schrieb Krzysztof Kozlowski:
> On 10/02/2025 17:44, Alexander Dahl wrote:
> > The main rc oscillator will be needed for the OTPC to work properly.
> >
> > The new index introduced here was not used on the four affected SoC
> > clock drivers before, but for sama5d2 only (PMC_I2S1_MUX).
> >
> > Link: https://lore.kernel.org/linux-devicetree/20250207-jailbird-circus-bcc04ee90e05@thorsis.com/T/#u
> > Signed-off-by: Alexander Dahl <ada@thorsis.com>
> > ---
> >
> > Notes:
> > v2:
> > - new patch, not present in v1
> >
> > include/dt-bindings/clock/microchip,sam9x60-pmc.h | 3 +++
> > include/dt-bindings/clock/microchip,sam9x7-pmc.h | 3 +++
> > include/dt-bindings/clock/microchip,sama7d65-pmc.h | 3 +++
> > include/dt-bindings/clock/microchip,sama7g5-pmc.h | 3 +++
> > 4 files changed, 12 insertions(+)
> >
> > diff --git a/include/dt-bindings/clock/microchip,sam9x60-pmc.h b/include/dt-bindings/clock/microchip,sam9x60-pmc.h
> > index e01e867e8c4da..dcd3c74f75b54 100644
> > --- a/include/dt-bindings/clock/microchip,sam9x60-pmc.h
> > +++ b/include/dt-bindings/clock/microchip,sam9x60-pmc.h
> > @@ -16,4 +16,7 @@
> >
> > #define SAM9X60_PMC_PLLACK PMC_PLLACK /* 7 */
> >
> > +/* new from after bindings splitup */
> > +#define SAM9X60_PMC_MAIN_RC 6
>
> This is confusing me, because:
> 1. You still have holes in IDs

Yes, I was told to maintain the old values for interface stability in
series v1 feedback.

> 2. This should be placed in proper order by ID

Okay, no problem.

> 3. Why not using 4 - the next available empty ID?

The MAIN_RC clock is used on four out of thirteen (?) SoC variants
which all used the same IDs before. 6 is the first ID which is free
on all of sam9x60, sam9x7, sama7g5, and sama7d65. The last two
already use 4 for a different clock.

The whole splitup is to avoid even more and/or bigger holes, but is it
important where the existent holes are filled?

Technically if the next available empty ID should be used it would be
4 for sam9x60 and sam9x7, 2 for sama7d65, and 6 for sama7g5. I
thought it would be nice to use the same value instead to make
somewhat compatible to the old approach.

Greets
Alex