Re: [EXTERNAL] [PATCH v1 1/1] i2c: designware: Add ACPI ID MSFT0006 for Microsoft Cobalt SoCs

[Siddharth Chintamaneni]

On Mon, 9 Nov 2026 at 04:34, Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> On Sun, Nov 08, 2026 at 11:45:00AM +0100, Wolfram Sang wrote:
> >
> > > For Cobalt, the firmware exposes the designware input clock frequency
> > > through the ACPI HCLK object.
> > > Is there an existing way to retrieve or configure this clock frequency
> > > through the ACPI tables, rather than hardcoding it in the driver?
> >
> > Calling for Andy here for being the designware + ACPI expert.
>
> We don't have the common way, it's unspecified. However, many drivers and some
> firmwares adopted the "clock-frequency" property. Unfortunately for I2C it means
> the clock of the bus, and not functional clock of the controller. So, I'm
> afraid you will need to have your own custom solution. Also makes sense to look
> what ARM people do in the same situtions (I know that Qualcomm tries hard to
> enable ACPI on laptops, if I was you, I would ask them first).
>

Thanks Andy for the suggestion. Not sure how to reach out to Qualocomm
ppl, I'll figure that out. I'll re-spin the patch for now.

> --
> With Best Regards,
> Andy Shevchenko
>
>