Re: [PATCH net-next 3/3] dpll: zl3073x: add hwmon support for input reference frequencies

[Ivan Vecera <ivecera@redhat.com>]

On 3/25/26 4:56 PM, Vadim Fedorenko wrote:
> On 25/03/2026 11:19, Ivan Vecera wrote:
>>
>>
>> On 3/24/26 10:36 PM, Jakub Kicinski wrote:
>>> On Tue, 24 Mar 2026 13:59:19 +0100 Ivan Vecera wrote:
>>>>>> In the hardware monitoring world one would have min/max attributes 
>>>>>> and
>>>>>> one or more alarm attributes. I never heard about the idea of 
>>>>>> reporting
>>>>>> deviations, and for typical hardware monitoring attributes it does 
>>>>>> not
>>>>>> really make sense. What would be a "deviation" of a temperature/
>>>>>> voltage/current/power/humidity sensor ? Such attributes typically 
>>>>>> have
>>>>>> an operational range, and they are allowed and even expected to
>>>>>> fluctuate within that range.
>>>>>
>>>>> Ivan, my take on all the above is that using the HWmon interface 
>>>>> here is
>>>>> stretching it too much. I think it would be better to move debugfs
>>>>> and/or netlink events.
>>>>
>>>> I'd rather avoid debugfs... My proposal is to expose absolute measured
>>>> frequency attribute of dpll-pin and follow phase-offset-monitor
>>>> functionality:
>>>>
>>>> So:
>>>> * add real-frequency attribute to dpll pin
>>>> * add real-frequency-monitor attribute dpll device
>>>> * user will be able to enable/disable monitoring by enabling/disabling
>>>>     real-frequency-monitor feature (similarly to phase-offset-monitor)
>>>>
>>>> Thoughts?
>>>
>>> I don't have a strong opinion. IDK where to draw the line between DPLL
>>> and "random functionality some devices may have". We have 3 DPLL
>>> maintainers, let's see what their majority opinion is..
>>
>> I think that line has already been crossed by temperature reporting,
>> which has been there since the beginning. Actual frequency measurement
>> is, in my opinion, much closer to the DPLL world than temperature 
>> reporting. :-)
> 
> Frequency measurements are DPLL-world properties indeed. Temperature
> reporting was added as it has some influence on the stability of DPLL 
> devices as well as on any oscillators.
> 
>> Anyway, I have the relevant patch-set already prepared, so I can submit
>> it if you want to see it.
> Feel free to submit, I'll be happy to review it.
> 
Thanks, will do..

Ivan