Re: [PATCH v7 16/16] pinctrl: qcom: make the pinmuxing strict

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On Wed, Sep 3, 2025 at 12:38 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxx> wrote:
>
> On Wed, Sep 03, 2025 at 12:34:00PM +0200, Bartosz Golaszewski wrote:
> > On Wed, Sep 3, 2025 at 12:22 PM Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxx> wrote:
> > > On Wed, Sep 03, 2025 at 09:33:34AM +0200, Bartosz Golaszewski wrote:
> > > > On Tue, Sep 2, 2025 at 10:46 PM Andy Shevchenko
> > > > <andy.shevchenko@xxxxxxxxx> wrote:
> > > > > On Tue, Sep 2, 2025 at 8:42 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
> > > > > > On Tue, Sep 2, 2025 at 4:38 PM Andy Shevchenko
> > > > > > <andriy.shevchenko@xxxxxxxxx> wrote:
> > > > > > > On Tue, Sep 02, 2025 at 01:59:25PM +0200, Bartosz Golaszewski wrote:
>
> ...
>
> > > > > > > > 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.
> > > > > > >
> > > > > > > How does this keep (or allow) I²C generic recovery mechanism to work?
> > > >
> > > > Anyway, what is your point? I don't think it has any impact on this.
> > >
> > > If we have a group of pins that are marked as I²C, and we want to use recovery
> > > via GPIOs, would it be still possible to request as GPIO when controller driver
> > > is in the strict mode?
> >
> > Yes, if you mark that function as a "GPIO" function in the pin
> > controller driver.
>
> How would it prevent from requesting from user space?
>

It wouldn't, we don't discriminate between user-space and in-kernel
GPIO users. A function either is a GPIO or isn't. Can you point me to
the driver you're thinking about or is this a purely speculative
question?

Bartosz





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