Re[2]: [RFC 3/8] mfd:syscon: Introduce claim/read/write/release APIs

["Alexander Shiyan" <shc_work-JGs/UdohzUI@public.gmane.org>]

> On Wednesday 08 May 2013, Srinivas KANDAGATLA wrote:
> > From: Srinivas Kandagatla <srinivas.kandagatla-qxv4g6HH51o@public.gmane.org>
> > 
> > This patch introduces syscon_claim, syscon_read, syscon_write,
> > syscon_release APIs to help drivers to use syscon registers in much more
> > flexible way.
> > 
> > With this patch, a driver can claim few/all bits in the syscon registers
> > and do read/write and then release them when its totally finished with
> > them, in the mean time if another driver requests same bits or registers
> > the API will detect conflit and return error to the second request.
> > 
> > Reason to introduce this API.
> > System configuration/control registers are very basic configuration
> > registers arranged in groups across ST Settop Box parts. These registers
> > are independent of IP itself. Many IPs, clock, pad and other functions
> > are wired up to these registers.
> > 
> > In many cases a single syconf register contains bits related to multiple
> > devices, and therefore it need to be shared across multiple drivers at
> > bit level. The same IP block can have different syscon mappings on
> > different SOCs.
> > 
> > Typically in a SOC there will be more than hundreds of these registers,
> > which are again divided into groups.
> > 
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla-qxv4g6HH51o@public.gmane.org>
> > CC: Stuart Menefy <stuart.menefy-qxv4g6HH51o@public.gmane.org>
> 
> My feeling is that syscon is the wrong place for this functionality,
> since regmap already handles (some of?) these issues. If you need
> additional synchronization, it's probably best to extend regmap
> as needed so other code besides syscon can take advantage of that
> as well.
+1

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