Re: [PATCH v3] rust: regulator: add a bare minimum regulator abstraction

["Alexandre Courbot" <acourbot@nvidia.com>]

On Mon May 19, 2025 at 8:54 PM JST, Benno Lossin wrote:
> On Mon May 19, 2025 at 12:52 PM CEST, Daniel Almeida wrote:
>>> I just mean the cases where users will want to enable and disable the
>>> regulator more frequently than just enabling it at probe time.
>>
>> This is already possible through kernel::types::Either. 
>>
>> i.e.: the current design - or the proposed typestate one - can already switch
>> back and forth between Regulator and EnabledRegulator. Using Either makes it
>> just work, because you can change the variant at runtime without hassle. This
>> lets you consume self in an ergonomic way.
>
> Have you tried to write such a use-case using `Either`? My personal
> experience with `Either` was pretty horrible, since you always have to
> match on it before you can do anything to the values. It's not really
> ergonomic.
>
> I think we should remove it, as it also doesn't have any users at the
> moment. Anyone that needs it should define a custom enum for their
> use-case.
>
> And effectively an `Either<Regulator, EnabledRegulator>` is just a
> `Regulator<Switch>` in Alexandre's proposal if I understood it
> correctly.

Exactly. And btw, there is no reason to block the merging of a simple
version with just enabled and disabled types while we discuss the rest,
as long as it is implemented as a typestate. Adding more ways to control
the enabled status just involves adding new types to be given as
arguments to `Regulator<>` and their respective `impl` blocks, so it can
be done incrementally on top of that base, which I believe everybody
agrees is sound.