On Thu, Nov 06, 2014 at 01:33:24AM +0400, Dmitry Eremin-Solenikov wrote:

2014-11-03 16:43 GMT+03:00 Linus Walleij [off-list ref]:

quoted

Yes that's the point: if you use regmap mmio you get the RMW-locking
for free, with the regmap implementation.

Just to be more concrete. Currently locomo_gpio_ack_irq() function uses
one lock and one unlock for doing 3 consecutive RMW I I convert locomo
to regmap, will that be 3 lock/unlock calls or still one? (Or maybe I'm
trying to be over-protective here and adding more lock/unlock cycles
won't matter that much?)

You'll get three lock/unlocks, we could add an interface for bulk
updates under one lock if it's important though.

Next question: if I have to export regmap to several subdrivers, is it better
to have one big regmap or to have one-map-per-driver approach?

One regmap for the physical register map which is shared between all the
users.