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Subject: Re: [PATCH v8 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till
 calibration is done
To:     Dmitry Osipenko <digetx@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>
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From:   Sowjanya Komatineni <skomatineni@nvidia.com>
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Date:   Wed, 5 Aug 2020 10:46:03 -0700
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On 8/5/20 10:34 AM, Dmitry Osipenko wrote:
> 05.08.2020 20:29, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> ...
>> UART_FST_MIPI_CAL is the clock used for calibration logic which is FSM
>> that goes thru sequence codes and when done waits for pads to be in
>> LP-11 to apply results.
>>
>> MIPI_CLK is controller gate clock which is also need to be kept enabled
>> as incase if it sees LP-11 it updates registers so its recommended to
>> have this clock enabled.
>>
>> We can cancel_calibration() in CSI only when csi/sensor stream on fails
>> and in which case there will be no LP-11 so we can unconditionally
>> disable MIPI_CLK.
>>
> There is no guarantee that the fail comes before the LP-11. For example,
> some odd camera driver may have a complicated enable sequence which may
> fail after enabling the hardware streaming.

MIPI_CLK to keep enable is for calibration logic to update results, but=20
like I said calibration logic uses UART_FST_MIPI_CAL clock. So even in=20
case if fail happens from sensor after having pads in LP-11 then,=20
calibration logic will still be running but result update will not=20
happen with clock disabled. But HW will not stuck as this is confirmed=20
from HW designer.