From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Fri, 21 Aug 2015 15:45:53 +0200
Subject: [PATCH v2 09/21] ARM: pxa: magician: Add OV9640 camera support
In-Reply-To: <55D65722.9030508@tul.cz>
References: <cover.1439843482.git.petr.cvek@tul.cz>
 <2889798.x6xcIzdYMU@wuerfel> <55D65722.9030508@tul.cz>
Message-ID: <1634812.ZDaECJ9ClW@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Friday 21 August 2015 00:39:30 Petr Cvek wrote:
> Dne 20.8.2015 v 22:26 Arnd Bergmann napsal(a):
> > On Thursday 20 August 2015 21:48:20 Robert Jarzmik wrote:
> >> Petr Cvek <petr.cvek@tul.cz> writes:
> >>
> >>> +     mdelay(3);
> >> Okay, there are several mdelay(3) in this file.
> >>
> >> Could you please test if removing these mdelays prevents the camera from working
> >> ? If not, I'd like to have them removed.
> >>
> >>
> > 
> > FWIW, it might be possible to replace some of them with msleep() calls,
> > potentially after replacing spinlocks with mutexes where necessary.
> > 
> >       Arnd
> > 
> 
> Datasheet says:
> 
>         tS:RESET        Setting time after software/hardware reset      1 ms
> 
> So at least one ~1 ms should be left there. Are msleep less than 20ms valid? 
> 
> (checkpatch: msleep < 20ms  can sleep for up to 20ms)

On most kernels, an msleep(1) will sleep somewhere between 1 and 3 milliseconds
(but could be much longer), while an mdelay(1) tries to sleep around one
millisecond, more or less.

	Arnd