Re: [PATCH net-next v2 1/3] dpll: add frequency monitoring to netlink spec
From: Jakub Kicinski
Date: Tue Mar 31 2026 - 23:06:46 EST
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 ?