Re: [PATCH 1/2] mfd: arizona: Add GPIO maintain state flag

[Linus Walleij]

On Thu, Apr 13, 2017 at 11:15 AM, Charles Keepax
<ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Apr 11, 2017 at 10:34:27AM +0100, Richard Fitzgerald wrote:

>> 3) The codec only has to be kept awake while any such GPIO is actually
>> in use. See (2)
>
> Yeah option 3 is the primary issue here, we only want to keep the
> CODEC enabled whilst specific GPIOs are in use. As GPIOs can be
> dynamically requested/released by things in the kernel we want to
> know which GPIOs require the CODEC to be kept alive. Also in the
> future one might be tempted to add maintain whilst high and
> maintain whilst low options for lines with pulls on them to
> further optimise power.

Why does this have to be encoded as information in the device
tree? Isn't it better to use a static table in the driver?

I don't see what use system integrators and others playing
around with the device tree has of this, it will just be confusing
to them if it is a chip-internal detail.

Yours,
Linus Walleij