linux-kernel - Re: [PATCH 3/3] mfd: arizona: Use new regmap features for manual register patch

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Message-ID: <20140225093723.GE5438@opensource.wolfsonmicro.com>
Date:	Tue, 25 Feb 2014 09:37:23 +0000
From:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	broonie@...nel.org, gregkh@...uxfoundation.org,
	sameo@...ux.intel.com, linux-kernel@...r.kernel.org,
	patches@...nsource.wolfsonmicro.com
Subject: Re: [PATCH 3/3] mfd: arizona: Use new regmap features for manual
	register patch

On Mon, Feb 24, 2014 at 04:10:42PM +0000, Lee Jones wrote:
> > On the wm5102 the register patches are applied manually, rather than by
> > the regmap core. This application is wrapped in calls to
> > regcache_cache_bypass. However, this is dangerous as other threads may
> > be accessing the hardware at the same time as the pm_runtime operations
> > and if they do so during the period whilst cache_bypass is enabled those
> > writes will miss the cache when they shouldn't.
> > 
> > Apply the register patch using the new regmap_apply_patch function to
> > avoid this problem. Also remove the call to regcache_cache_bypass from
> > the hardware patch application as it is unneeded there and creates a
> > similar window for writes to miss the cache.
> > 
> > Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> > ---
> >  drivers/mfd/arizona-core.c  |    4 ----
> >  drivers/mfd/wm5102-tables.c |   19 ++-----------------
> >  2 files changed, 2 insertions(+), 21 deletions(-)
> 
> Applied, thanks.

Apologies this patch depends on the previous patch I am still
working Mark's comments for. So this can't really be applied at
the moment.

Thanks,
Charles
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