Re: [PATCH RFC/RFT] pinctrl: qcom: make the pinmuxing strict

[Bartosz Golaszewski]

On Thu, Jun 26, 2025 at 9:06 PM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 6/25/25 5:37 PM, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> >
> > The strict flag in struct pinmux_ops disallows the usage of the same pin
> > as a GPIO and for another function. Without it, a rouge user-space
> > process with enough privileges (or even a buggy driver) can request a
> > used pin as GPIO and drive it, potentially confusing devices or even
> > crashing the system. Set it globally for all pinctrl-msm users.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > ---
>
> SC8280XP CRD breaks with this.. looks like there's a conflict between
> regulator-fixed accessing the pin with gpiod APIs and setting a pinmux:
>
> [    5.095688] sc8280xp-tlmm f100000.pinctrl: pin GPIO_25 already requested by regulator-edp-3p3; cannot claim for f100000.pinctrl:570
> [    5.107822] sc8280xp-tlmm f100000.pinctrl: error -EINVAL: pin-25 (f100000.pinctrl:570)
>
>
> Konrad

Yeah, I would be surprised if nothing broke.It's probably worth
looking into the implementation of the strict flag as it makes every
muxed pin unavailable as GPIO even if - like in this case - the
function *is* "gpio". Of course the "gpio" string has no real meaning
to the pinctrl core, it's just a name but it would be awesome if we
could say for a given function that this means GPIO and as such should
be available to the GPIOLIB API.

Bart