Re: [PATCH net-next v8 2/3] dpll: zl3073x: add channel ToD, phase step and TIE operations

[Ivan Vecera <ivecera@redhat.com>]

Sashiko comments with my replies:

 > Can this loop spin out its retry budget without ever giving the
 > condition a chance to become true? [...]
 > On a fast bus where the ToD command completes before the semaphore
 > is re-read, all 20 iterations can finish well inside the 20 ms window

Testing on I2C at both 100 kHz and 400 kHz shows that a single
iteration takes approximately 17-19 ms regardless of bus speed.
The iteration time is dominated by the device's internal processing
of the ToD read commands, not bus transfer time. With 20 retries
the budget is 340-380 ms, well beyond the 20 ms margin window.

 > the kerneldoc for zl3073x_chan_tie_write() states delta_ns "must be
 > in (-1s, 1s)" and nothing in the function enforces it. [...]
 > Would an explicit range check on delta_ns be worth adding here?

Both in-tree callers already bound the input as you noted. The range
guard was intentionally removed in this version at the reviewer's
request — the internal API should trust its callers rather than
re-validate inputs already checked by the PTP core. The kernel-doc
documents the precondition for future callers.

Thanks,
Ivan