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Subject: Re: [PATCH v7 09/10] media: tegra-video: Add CSI MIPI pads
 calibration
To:     Sowjanya Komatineni <skomatineni@nvidia.com>,
        thierry.reding@gmail.com, jonathanh@nvidia.com, frankc@nvidia.com,
        hverkuil@xs4all.nl, sakari.ailus@iki.fi, robh+dt@kernel.org,
        helen.koike@collabora.com
Cc:     gregkh@linuxfoundation.org, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1596231144-12554-1-git-send-email-skomatineni@nvidia.com>
 <1596231144-12554-10-git-send-email-skomatineni@nvidia.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <af5506d4-52a4-8693-b95b-d1e0a9a53e79@gmail.com>
Date:   Sat, 1 Aug 2020 04:04:38 +0300
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01.08.2020 00:32, Sowjanya Komatineni пишет:
> CSI MIPI pads need to be enabled and calibrated for capturing from
> the external sensor or transmitter.
> 
> MIPI CAL unit calibrates MIPI pads pull-up, pull-down and termination
> impedances. Calibration is done by co-work of MIPI BIAS pad and MIPI
> CAL control unit.
> 
> Triggering calibration start can happen any time after MIPI pads are
> enabled but calibration results will be latched and applied to MIPI
> pads by MIPI CAL unit only when the link is in LP11 state and then
> calibration status register gets updated.
> 
> This patch enables CSI MIPI pads and calibrates them during streaming.
> 
> Tegra CSI receiver is able to catch the very first clock transition.
> So, CSI receiver is always enabled prior to sensor streaming and
> trigger of calibration start is done during CSI subdev streaming and
> status of calibration is verified after sensor stream on.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
>  drivers/staging/media/tegra-video/TODO  |  1 -
>  drivers/staging/media/tegra-video/csi.c | 61 +++++++++++++++++++++++++++++++--
>  drivers/staging/media/tegra-video/csi.h |  2 ++
>  drivers/staging/media/tegra-video/vi.c  | 28 ++++++++++++---
>  4 files changed, 84 insertions(+), 8 deletions(-)

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>