Messages in this thread | | | From | Chen-Yu Tsai <> | Date | Tue, 3 Oct 2017 23:08:11 +0800 | Subject | Re: [PATCH v3 12/12] ARM: dtsi: axp81x: set pinmux for GPIO0/1 when used as LDOs |
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On Tue, Oct 3, 2017 at 10:47 PM, Maxime Ripard <maxime.ripard@free-electrons.com> wrote: > Hi Linus, > > On Tue, Oct 03, 2017 at 09:27:17AM +0000, Linus Walleij wrote: >> On Mon, Oct 2, 2017 at 2:08 PM, Quentin Schulz >> <quentin.schulz@free-electrons.com> wrote: >> >> > On AXP813/818, GPIO0 and GPIO1 can be used as LDO as (respectively) >> > ldo_io0 and ldo_io1. >> (...) >> > + gpio0_ldo: gpio0_ldo { >> > + pins = "GPIO0"; >> > + function = "ldo"; >> > + }; >> (...) >> > + 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
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