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

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Message-ID: <20150508102019.GX22845@sirena.org.uk>
Date:	Fri, 8 May 2015 11:20:19 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Nariman Poushin <nariman@...nsource.wolfsonmicro.com>
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 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.  

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.

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