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

From: Dmitry Osipenko <digetx@gmail.com>
To: Sowjanya Komatineni <skomatineni@nvidia.com>,
	Thierry Reding <thierry.reding@gmail.com>
Cc: jonathanh@nvidia.com, frankc@nvidia.com, hverkuil@xs4all.nl,
	sakari.ailus@iki.fi, robh+dt@kernel.org,
	helen.koike@collabora.com, gregkh@linuxfoundation.org,
	linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till calibration is done
Date: Thu, 6 Aug 2020 21:01:54 +0300	[thread overview]
Message-ID: <26ed2841-db5d-aeb0-11c7-cbe2ddd1d76b@gmail.com> (raw)
In-Reply-To: <ed79b201-85ba-f725-c5fa-fcde0761bc3d@nvidia.com>

06.08.2020 20:52, Sowjanya Komatineni пишет:
...
> Right mutex_unlock should happen at end of finish_calibration.
> 
> With keeping mutex locked in start, we dont have to check for active to
> be 0 to issue start as mutex will keep it locked and other pads
> calibration can only go thru when current one is done.
> 
> So instead of below sequence, its simpler to do this way?
> 
> start_calibration()
> 
> - mutex_lock
> 
> - wait for 72uS after start
> 
> finish_calibration()
> 
> - keep check for ACTIVE = 0 and DONE = 1

I think only the DONE bits which correspond to the mipi_device->pads
bitmask should be awaited.

> - mutex_unlock()

Perhaps the start_calibration() also needs to be changed to not touch
the MIPI_CAL_CONFIG bits of the unrelated pads?

Otherwise sounds good to me.