RE: [PATCH net-next v5 1/4] dpll: add DPLL_PIN_TYPE_INT_NCO pin type

[Kubalewski, Arkadiusz]

>From: Jiri Pirko <jiri@xxxxxxxxxxx>
>Sent: Tuesday, June 9, 2026 10:51 AM
>
>Mon, Jun 08, 2026 at 07:03:46PM +0200, arkadiusz.kubalewski@xxxxxxxxx
>wrote:
>>>From: Ivan Vecera <ivecera@xxxxxxxxxx>
>>>Sent: Monday, June 8, 2026 5:48 PM
>>>
>>>On 6/8/26 4:43 PM, Kubalewski, Arkadiusz wrote:
>>>>> From: Ivan Vecera <ivecera@xxxxxxxxxx>
>>>>> Sent: Sunday, May 31, 2026 9:44 PM
>>>>> ...
>>>>>        -
>>>>>          name: gnss
>>>>>          doc: GNSS recovered clock
>>>>> +      -
>>>>> +        name: int-nco
>>>>> +        doc: |
>>>>> +          Device internal numerically controlled oscillator.
>>>>> +          When connected as a DPLL input, the DPLL enters NCO mode
>>>>> +          where the output frequency is adjusted by the host via
>>>>> +          the PTP clock interface.
>>>>
>>>> Hi Ivan!
>>>>
>>>> How would you control this in case of automatic mode dpll?
>>>> Automatic mode DPLL shall be controlled on HW level, such pin brakes
>>>> that rule and requires some driver magic to show it is higher
>>>> priority then the rest of the pins?
>>>
>>>The NCO pin can be connected only in manual mode. In other words a DPLL
>>>in automatic mode cannot select NCO pin (switch to NCO mode) by its own.
>>>
>>
>>Being picky on DPLL_MODE for enabling feature is not something we can
>>allow if it is not related to HW limitation, is it?
>>Could you please elaborate why it is not possible for AUTOMATIC mode?
>
>In automatic mode, the pin selection logic is defined upon prio. I can
>imagine that if NCO pin has the highest prio of the available ones,
>it gets picked. I would be aligned 100% with automatic mode behaviour.
>Is there a real usecase for it?
>
>[..]

This is not true. AUTOMATIC mode is HW solution, SW driver ONLY
configures priorities on the inputs, not manages the active inputs.
This brakes that behavior, the SW driver would have to manually
override the AUTMATIC mode to be fed from such NCO pin as it doesn't
exists on it's priority list, HW cannot pick or use it.

The real use case is that any DPLL can switch the mode to this one
instead of implementing MANUAL mode just to use the feature with a
'virtual' pin.