Re: [PATCH v5 1/7] regulator: core: Add "enable and wait" functions

[Chen-Yu Tsai]

On Tue, Aug 25, 2026 at 12:33 PM Chen-Yu Tsai <wenst@xxxxxxxxxxxx> wrote:
>
> In device power sequencing and initialization use cases, it is common
> for the driver to enable the regulator and then wait for a certain
> period of time to pass before continuing.
>
> In cases where the regulator supply is always on, or has been turned on
> or left on by another consumer, the driver could shorten the delay or
> skip it altogether, provided that enough time has already passed since
> the regulator was _actually_ turned on.
>
> Tracking this requires support from the regulator core. Introduce a
> "last turned on" timestamp field to the regulator device, and "enable
> and wait" functions to the single and bulk regulator consumer APIs.
> The existing "enable without wait" functions are then converted to
> macros that expand to the new functions.
>
> The timestamp is updated each time the regulator is actually turned on.
> For regulators left on by hardware default or by firmware, the core will
> set the timestamp if it detects it was left on and its supply (and their
> supply, and so on) is on as well. This is unfortunately best effort
> only. The core can only assume a dangling regulator (one without a
> supply) has power. This also applies to the dummy regulator.
>
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> ---
> Changes since v4:
> - Try to update last_on timestamp for regulators that were left on

Sashiko flaged a few issues with the changes:

- _regulator_is_enabled() called and subsequent timestamp update
  without lock
- bulk consumer wait_us incorrectly assigned
- _regulator_is_enabled() could return an error

Will fix and send a new version. I probably should get a local AI review
working first.


ChenYu