[RFC PATCH v2] phy: qcom-mipi-csi2: round the requested settle interval up

[Jizhou Tong]

Hi Bryan,

I checked the zero-count case raised by Sashiko against media-next
(d7e7bca71698) and the rounding patch. Both the base driver and the
patched driver return zero when the calculated interval is exactly
six integer timer periods, and lanes_enable() rejects it with -ENODEV.

For example, link_freq = 600000000 Hz and timer_clk_rate = 66666666 Hz
produce a 90000 ps interval and a 15000 ps integer timer period. The
helper returns zero before and after the patch. This is a software
boundary case, not a clock configuration I have tested on hardware.

Is a programmed settle count of zero valid on the supported PHYs, or
is rejecting it intentional? If it is valid, the helper would need to
distinguish it from an unrepresentable interval, with the caller checking
for an error separately.

The rounding RFC preserves the existing zero-count handling. I would
keep any change to that hardware policy separate from the rounding fix.

Best regards,
Jizhou Tong