Rockchip RK3188 I2C driver

[heiko@sntech.de (Heiko Stübner)]

Am Freitag, 18. April 2014, 01:06:27 schrieb Max Schwarz:
> On Thursday 17 April 2014 at 19:38:35, Mark Brown wrote:
> > If you're only doing a few accesses then surely there's no meaningful
> > overhead from just writing what you want?  So long as you don't cache
> > these registers regmap won't really get in the way.
> 
> I think Heiko and I have been operating under the misconception that caching
> is somehow enabled by default - which is not the case. Thanks for clearing
> that up ;-)

Actually I think it's the other way around :-).

See regmap_read() calling _reagmap_read(), which in turn calls 
regcache_read(), except when map->cache_bypass is enabled, which then checks 
the volatile setting for the individual register.

So I guess we'd need to teach syscon to handle volatile registers (mark our 
grf ones as such) and then could leave the rest alone.


Heiko