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

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Date:	Tue, 25 Feb 2014 10:02:16 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
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 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.

It's a good idea to let us know about any inter-patch dependencies, so
we may act accordingly. I'll remove this from my -next branch for now.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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