On Tue, Oct 3, 2017 at 10:47 PM, Maxime Ripard
[off-list ref] wrote:

Hi Linus,

On Tue, Oct 03, 2017 at 09:27:17AM +0000, Linus Walleij wrote:

quoted

On Mon, Oct 2, 2017 at 2:08 PM, Quentin Schulz
[off-list ref] wrote:

quoted

On AXP813/818, GPIO0 and GPIO1 can be used as LDO as (respectively)
ldo_io0 and ldo_io1.

(...)

quoted

+               gpio0_ldo: gpio0_ldo {
+                       pins = "GPIO0";
+                       function = "ldo";
+               };

(...)

quoted

+                       pinctrl-names = "default";
+                       pinctrl-0 = <&gpio0_ldo>;
                        /* Disable by default to avoid conflicts with GPIO */
                        status = "disabled";

So this is still by default disabled, but you make the default
mode something called "ldo".

And I think that is to be understood as a low-dropout regulator?

So is the idea that this should be represented as a regulator
in the end?

Then I think the state name should not be "default" rather
something like "regulator" and "default" should be the GPIO
mode, as I guess something like that exists.

Activating a regulator using pin control "default" mode is
not very pretty. It would probably be unintuitive and end
up wasting power because people will get confused about
what is going on.

That's not really it. The PMIC has pins that can be muxed either to
(regular) GPIOs, an ADC or to an LDO regulator.

This is just muxing, the regulator will be enabled and disabled
separately through another register. If it wasn't the case, it would
indeed be very messy.

No. Actually they are controlled in the same register, so it is
very messy. The muxing options are:

    - 0: drive low
    - 1: drive high
    - 2: input with interrupt triggering
    - 3: LDO on
    - 4: LDO off
    - 5~7: floating (or ADC)

ChenYu