Re: [PATCH v8 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till calibration is done

From: Dmitry Osipenko
Date: Thu Aug 06 2020 - 13:22:23 EST

06.08.2020 19:51, Sowjanya Komatineni пишет:
>>>> What about to add 72us delay to the end of start_calibration() in order
>>>> to ensure that FSM is finished before LP-11?
>>> Why we should add 72uS in start_calibration() when can use same
>>> finish_calibration() for both pass/fail cases?
>>> Only timing loose we see is in case of failure we still wait for 250ms
>>> and as this is failing case I hope should be ok.
>> You said that calibration settings are applied to pads on LP-11, but if
>> LP-11 happens before FSM is finished, then what values will be applied
>> if any?
> No calibration logic will check for LP-11 only after finishing
> calibration sequence codes.
> After that if it sees LP-11, it will apply results to pads and DONE bit
> will then be set to 1 indication pad results update.

Are you sure that HW doesn't use level-triggered logic for LP-11 signal?

> Unfortunately like I said we don't have status indication for
> calibrating finished before waiting for LP-11.

This is not a problem if hardware can cope with LP-11 happened at the
time of calibration. If hardware can't cope with that, then somethings
needs to be done about it.