On Fri, Sep 23, 2016 at 3:08 PM, Eric Anholt <e...@anholt.net> wrote:
> Sort of related: I also worry that we have races with the firmware for > the platform GPIO bits, since both ARM and firmware are doing RMWs (or, > even worse, maybe just Ws?) of the registers controlled by the pinctrl > driver. Hopefully I can get the firmware to pass control of devices > like this over to Linux, with firmware making requests to us, but I > don't know if that will happen and we may need to access other GPIOs > using this interface :( For the race with firmware I have no good solutions, it's just one of those things I guess :( When two kernel drivers compete about registers, say for example one driver needs to RMW bits 0-5 and another driver needs to RMW bits 7-11, the right solution is usually to use syscon and then regmap-mmio will deal with the concurrency as part of regmap_update_bits() etc. Yours, Linus Walleij