Subject: Re: [PATCH net-next v2 1/3] dpll: add frequency monitoring to netlink spec

From: Jakub Kicinski <[email-masked]>
Date: Tue, 31 Mar 2026 20:05:35 -0700

On Mon, 30 Mar 2026 12:55:03 +0200 Ivan Vecera wrote:
> Add DPLL_A_FREQUENCY_MONITOR device attribute to allow control over
> the frequency monitor feature. The attribute uses the existing
> dpll_feature_state enum (enable/disable) and is present in both
> device-get reply and device-set request.
> 
> Add DPLL_A_PIN_MEASURED_FREQUENCY pin attribute to expose the measured
> input frequency in Hz. The attribute is present in the pin-get reply.

> +      -
> +        name: frequency-monitor
> +        type: u32
> +        enum: feature-state
> +        doc: Receive or request state of frequency monitor feature.

reads a bit clunkily - how about:

	Current or desired state of the frequency monitor feature.

?

> +          If enabled, dpll device shall measure all currently available
> +          inputs for their actual input frequency.
>    -
>      name: pin
>      enum-name: dpll_a_pin
> @@ -456,6 +463,13 @@ attribute-sets:
>            Value is in PPT (parts per trillion, 10^-12).
>            Note: This attribute provides higher resolution than the standard
>            fractional-frequency-offset (which is in PPM).
> +      -
> +        name: measured-frequency
> +        type: u64
> +        doc: |
> +          The measured frequency of the input pin in Hz.
> +          This is the actual frequency being received on the pin,
> +          as measured by the dpll device hardware.

If we make this a u64 should it be fixed point? Seems dubious that we'd
ever be able to measure >4Ghz frequencies, much more likely that we'd 
want sub-1 precision ? So let's say this is fixed point 34.30 ?