Thu, Apr 30, 2026 at 07:36:10PM +0200, ivecera@redhat.com wrote:

Move the fractional-frequency-offset-ppt attribute from the top-level
pin attributes into the pin-parent-device nested attribute set. This
makes it consistent with phase-offset which is already per-parent and
clarifies that FFO PPT represents the frequency difference between
a pin and its parent DPLL device.

The top-level fractional-frequency-offset attribute (in PPM) remains
unchanged for backward compatibility.

That is odd. The ppt one was added just for higher precision but was
semantically the same. Now you change it. Could you still treat both the
same?

Distinguish the two contexts in the ffo_get callback by passing
dpll=NULL for the top-level (rx vs tx symbol rate) call and a valid
dpll pointer for the nested (pin vs parent DPLL) call. Update mlx5
and zl3073x drivers to return -ENODATA for the nested context they
do not yet support.

Add documentation for both FFO attributes to dpll.rst.

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