Re: [RFC PATCH v3 16/18] gpu: host1x: mipi: Split tegra_mipi_calibrate and tegra_mipi_wait

[Sowjanya Komatineni]

On 7/16/20 1:38 PM, Dmitry Osipenko wrote:
> 15.07.2020 07:20, Sowjanya Komatineni ÐÐÑÐÑ:
> > SW can trigger MIPI pads calibration any time after power on
> > but calibration results will be latched and applied to the pads
> > by MIPI CAL unit only when the link is in LP-11 state and then
> > status register will be updated.
> >
> > For CSI, trigger of pads calibration happen during CSI stream
> > enable where CSI receiver is kept ready prior to sensor or CSI
> > transmitter stream start.
> >
> > So, pads may not be in LP-11 at this time and waiting for the
> > calibration to be done immediate after calibration start will
> > result in timeout.
> >
> > This patch splits tegra_mipi_calibrate() and tegra_mipi_wait()
> > so triggering for calibration and waiting for it to complete can
> > happen at different stages.
> >
> > Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> > ---
> ...
> >   int tegra_mipi_calibrate(struct tegra_mipi_device *device)
> >   {
> > @@ -370,12 +381,10 @@ int tegra_mipi_calibrate(struct tegra_mipi_device *device)
> >   	value |= MIPI_CAL_CTRL_START;
> >   	tegra_mipi_writel(device->mipi, value, MIPI_CAL_CTRL);
> >   
> > -	err = tegra_mipi_wait(device->mipi);
> Doesn't MIPI clock need to be enabled during of the calibration process?
MIPI clock is already enabled in tegra_mipi_calibrate
> >   	mutex_unlock(&device->mipi->lock);
> >   	clk_disable(device->mipi->clk);
> >   
> > -	return err;
> > +	return 0;
> >   }
> >   EXPORT_SYMBOL(tegra_mipi_calibrate);