Re: [Intel PMC TGPIO Driver 0/5] Add support for Intel PMC Time GPIO Driver with PHC interface changes to support additional H/W Features

Richard Cochran
2020-02-03T04:08:45Z

On Wed, Dec 11, 2019 at 01:48:47PM -0800, christopher.s.hall@intel.com wrote:
> The ART frequency is not adjustable. In order, to implement output
> adjustments an additional edge-timestamp API is added, as well, as
> a periodic output frequency adjustment API. Togther, these implement
> equivalent functionality to the existing SYS_OFFSET_* and frequency
> adjustment APIs.

I don't see a reason for a custom, new API just for this device.

The TGPIO input clock, the ART, is a free running counter, but you
want to support frequency adjustments. Use a timecounter cyclecounter
pair.

Let the user dial a periodic output signal in the normal way.

Let the user change the frequency in the normal way, and during this
call, adjust the counter values accordingly.

Thanks,
Richard