Re: [PATCH v2 3/4] gpio: Add RDA Micro GPIO controller support

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Sat, Oct 19, 2019 at 6:05 PM Manivannan Sadhasivam
<manivannan.sadhasivam@xxxxxxxxxx> wrote:
> On Wed, Oct 16, 2019 at 02:41:32PM +0200, Linus Walleij wrote:

> > select GPIO_GENERIC
>
> hmm.. I don't think this driver can use it. Please see the justification
> below.
(...)
> As you can see in this driver, there are 2 separate registers needs to be
> read in order to get the value. RDA_GPIO_VAL needs to be read when the pin
> is in input state and RDA_GPIO_SET needs to be read when the pin is in output
> state.
>
> The MMIO driver relies on a single `dat` register to read the GPIO state and
> this won't fit for this driver and hence my justification for not using it.

Use RDA_GPIO_VAL for dat, then set BGPIOF_READ_OUTPUT_REG_SET
and the mmio core will do what you want I think? That's what the flag is
for IIUC.

Maybe we should document it better :/

Yours,
Linus Walleij