Re: [PATCH RESEND v2] rust: regulator: add a bare minimum regulator abstraction

[Maud Spierings]

On 3/27/25 12:32, Mark Brown wrote:
> On Wed, Mar 26, 2025 at 04:49:26PM -0300, Daniel Almeida wrote:
> > > On 26 Mar 2025, at 15:56, Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> > > > +    /// Disables the regulator.
> > > > +    pub fn disable(self) -> Result<Regulator> {
> > > > +        // Keep the count on `regulator_get()`.
> > > > +        let regulator = ManuallyDrop::new(self);
>
> > > This looks like user code could manually call it which feels like asking
> > > for trouble?
>
> > Yes, user code can call this. My understanding is that drivers may want to
> > disable the regulator at runtime, possibly to save power when the device is
> > idle?
>
> > What trouble are you referring to?
>
> My understanding was that the enable was done by transforming a
> Regulator into an EnabledRegulator but if you can explicitly call
> disable() on an EnabledRegulator without destroying it then you've got
> an EnabledRegulator which isn't actually enabled.  Perhaps it's not
> clear to me how the API should work?

From my understanding, disable() takes ownership of self, it does not 
take a reference, so the EnabledRegulator is consumed and the Regulator 
is returned through the result. So EnabledRegulator will get dropped in 
this function which owns it.