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

[Sowjanya Komatineni <skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 7/16/20 1:38 PM, Dmitry Osipenko wrote:
> 15.07.2020 07:20, Sowjanya Komatineni пишет:
>> 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-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>> ---
> ...
>>   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);