linux-kernel - Re: [RFC PATCH v3 16/18] gpu: host1x: mipi: Split tegra_mipi_calibrate and tegra_mipi

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Message-ID: <4690e682-8495-2327-87c7-c2f06a7a479d@nvidia.com>
Date:   Thu, 16 Jul 2020 16:06:25 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>, <thierry.reding@...il.com>,
        <jonathanh@...dia.com>, <frankc@...dia.com>, <hverkuil@...all.nl>,
        <sakari.ailus@....fi>, <robh+dt@...nel.org>,
        <helen.koike@...labora.com>
CC:     <sboyd@...nel.org>, <gregkh@...uxfoundation.org>,
        <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-i2c@...r.kernel.org>
Subject: Re: [RFC PATCH v3 16/18] gpu: host1x: mipi: Split
 tegra_mipi_calibrate and tegra_mipi_wait


On 7/16/20 4:01 PM, Dmitry Osipenko wrote:
> 17.07.2020 01:49, Sowjanya Komatineni пишет:
>>> What keeps MIPI clock enabled after completion of the
>>> tegra_mipi_calibrate() invocation?
>> MIPI clock is disabled at end of tegra_mipi_calibrate and is re-enabled
>> during tegra_mipi_wait.
>>
>> I think I should fix this to keep the clock enabled till calibration
>> results are latched.
>>
>> All consumers of tegra_mipi_calibrate() will call tegra_mipi_wait().
>>
>> So will remove clk_disable mipi clk at end of tegra_mipi_calibrate() and
>> clk_enable mipi_clk at beginning of tegra_mipi_wait()
> Isn't it possible to perform the calibration after enabling CSI and
> before of starting the sensor streaming?
Currently this is what I am doing. Triggering calibration start during 
CSI receiver being ready and then sensor streaming will happen where 
internal MIPI CAL detects for LP -> HS transition and applies results to 
pads. So checking for calibration results after sensor stream is enabled