On Thu, Oct 29, 2020 at 01:27:08PM -0300, Ezequiel Garcia wrote:
> On Thu, 2020-10-29 at 14:15 +0000, Robin Murphy wrote:

> > Or maybe the regmap API itself deserves extending with a "deferred" 
> > operating mode where updates to the cached state can be separated from 
> > committing that state to the underlying hardware.

> > ...which, after a brief code search out of curiosity, apparently already 
> > exists in the form of regcache_cache_only()/regcache_sync(), so there's 
> > probably no need to reinvent it :)

> To be fair, and despite it could seem an anti-pattern, this particular
> wheel is so tiny and trivial, that I'm starting to seriously consider
> reinventing it.

> I've been thinking long about this but just can't seem to see exactly
> what benefit we're getting from using MMIO regmaps here,
> as opposed to just a simple macro with an index, a mask, and an offset.

As a rule of thumb if you're not using a cache or fitting into some
other higher level framework stuff that uses regmap then I wouldn't
bother for MMIO devices.