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

[Sowjanya Komatineni]

On 8/5/20 10:34 AM, Dmitry Osipenko wrote:
> 05.08.2020 20:29, Sowjanya Komatineni пишет:
> ...
> > 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 
like I said calibration logic uses UART_FST_MIPI_CAL clock. So even in 
case if fail happens from sensor after having pads in LP-11 then, 
calibration logic will still be running but result update will not 
happen with clock disabled. But HW will not stuck as this is confirmed 
from HW designer.