linux-kernel - Re: [RFC][PATCH] regmap: make REGCACHE_NONE maps return error on regcache

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Message-ID: <20150508103454.GA13160@opensource.wolfsonmicro.com>
Date:	Fri, 8 May 2015 11:34:54 +0100
From:	Nariman Poushin <nariman@...nsource.wolfsonmicro.com>
To:	Mark Brown <broonie@...nel.org>
Cc:	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com
Subject: Re: [RFC][PATCH] regmap: make REGCACHE_NONE maps return error on
	regcache_sync

On Fri, May 08, 2015 at 11:20:19AM +0100, Mark Brown wrote:
> On Fri, May 08, 2015 at 10:55:37AM +0100, Nariman Poushin wrote:
> > Signed-off-by: Nariman Poushin <nariman@...nsource.wolfsonmicro.com>
> > ---
> >  regcache currently causes a BUG_ON if cache_sync/sync_region is
> >  called on a map with cache_type REGCACHE_NONE. This is not
> >  consistent with the behaviour of regcache_read/write which
> >  currently just return -ENOSYS and only throws a BUG_ON if
> >  the cache_type is something that _should_ have cache ops,
> >  but doesn't. Sure your device might not work, it but doesn't
> >  seem right to panic the kernel. The other option I suppose
> >  is to change it to a WARN_ON.
> 
> Please submit patches in the format covered in SubmittingPatches, the
> changelog goes before the signoff.  
>

Will do, apologies.
 
> The reason this is so loud is that while it's reasonable that generic
> code could end up triggering a write it's difficult to see any way in
> which a sync could be triggered on a device without a cache without it
> being an obvious bug.  Since people frequently don't bother checking
> return codes loud log messages are our only real way of reporting this,
> given where syncs tend to happen it's not likely to happen in an obscure
> code path that won't get seen.

Fair enough, that makes sense.

Thanks
Nariman
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