On Wed, Jul 9, 2014 at 12:59 AM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > On Tue, Jul 8, 2014 at 3:26 AM, Bjorn Andersson > <bjorn.andersson@xxxxxxxxxxxxxx> wrote: > >> Most status bits, e.g. for GPIO and MPP input, is retrieved by reading >> the interrupt status registers, so this needs to be exposed to clients. >> >> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx> > > Hm do you mean you read the input *values* from the interrupt status > registers? > Due to the limited address space (I presume), many of the status bits on the pm8xxx are not exposed in any other place than through a banked register in the interrupt "block". So we have to read the interrupt status in order to get information related to things like gpio status or if a battery is present for charging. > What madness in that case.... :-) > Totally! > Anyway, since the driver is based on regmap, can't the children just > get a regmap * somehow and then just go read the same register > instead of having to add a special function for it? > That we have, and we have access to that part of the ssbi address space. Unfortunately, like everything else in these pmics, things are banked. So we need first a bank selector and then a read; so it's racy with the interrupt handler code doing the same thing. > When I look at it it seems like it's doing regmap strangely or > something, like it's one write then one read operation to get > the register(s) and isn't that all supposed to be hidden behind > regmap so you don't need the local lock chip->pm_irq_lock? > I guess one could have exposed a regmap that instead of exposing the ssbi address space presented a logical view of the pm8xxx registers; something like the bitplanes on Amiga. I prefer having a ssbi regmap for simplicity (and sanity) but then we need to have this read in the irq driver. Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
