[PATCH v4 05/12] power-domain: Add refcounting

[Fabio Estevam]

Hi Simon,

On Wed, Jan 29, 2025 at 7:22 AM Miquel Raynal <miquel.raynal at bootlin.com> wrote:
>
> It is very surprising that such an uclass, specifically designed to
> handle resources that may be shared by different devices, is not keeping
> the count of the number of times a power domain has been
> enabled/disabled to avoid shutting it down unexpectedly or disabling it
> several times.
>
> Doing this causes troubles on eg. i.MX8MP because disabling power
> domains can be done in recursive loops were the same power domain
> disabled up to 4 times in a row. PGCs seem to have tight FSM internal
> timings to respect and it is easy to produce a race condition that puts
> the power domains in an unstable state, leading to ADB400 errors and
> later crashes in Linux.
>
> CI tests using power domains are slightly updated to make sure the count
> of on/off calls is even and the results match what we *now* expect.
>
> As we do not want to break existing users while stile getting
> interesting error codes, the implementation is split between:
> - a low-level helper reporting error codes if the requested transition
>   could not be operated,
> - a higher-level helper ignoring the "non error" codes, like EALREADY and
>   EBUSY.
>
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>

Are you happy with this version?