Re: [PATCH v6 03/16] power: sequencing: Add pwrseq_power_is_on()

[Chen-Yu Tsai]

On Tue, Jul 21, 2026 at 5:08 PM Bartosz Golaszewski <brgl@xxxxxxxxxx> wrote:
>
> On Tue, 21 Jul 2026 08:53:58 +0200, Chen-Yu Tsai <wenst@xxxxxxxxxxxx> said:
> > The power sequencing consumer API already does power on state tracking
> > internally. Expose the state to consumers through pwrseq_power_is_on()
> > so that they don't have to reimplement it locally.
> >
> > Acked-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> > ---
> > Changes since v5:
> > - Reverted back to returning -EINVAL if descriptor is NULL
> >
> > Changes since v4:
> > - Make pwrseq_power_is_on() return 1 if descriptor is NULL, i.e. if
> >   the descriptor is optional, matching the other pwrseq consumer APIs
> >
> > Changes since v3:
> > - Added missing stub function for !POWER_SEQUENCING
> >
> > Changes since v2:
> > - New patch
> >
> > Needs to go in with "usb: hub: Power on connected M.2 E-key connectors"
> > as it is a build time dependency. Bartosz wants the change on an
> > immutable branch to pull into the pwrseq tree.
> > ---
> >  drivers/power/sequencing/core.c | 18 ++++++++++++++++++
> >  include/linux/pwrseq/consumer.h |  6 ++++++
> >  2 files changed, 24 insertions(+)
> >
> > diff --git a/drivers/power/sequencing/core.c b/drivers/power/sequencing/core.c
> > index 02f42da91598..72b96d36920e 100644
> > --- a/drivers/power/sequencing/core.c
> > +++ b/drivers/power/sequencing/core.c
> > @@ -968,6 +968,24 @@ int pwrseq_power_off(struct pwrseq_desc *desc)
> >  }
> >  EXPORT_SYMBOL_GPL(pwrseq_power_off);
> >
> > +/**
> > + * pwrseq_power_is_on() - Queries the last requested state of the power sequencer.
> > + * @desc: Descriptor referencing the power sequencer.
> > + *
> > + * This returns the last requested state of the power sequencer.
> > + *
> > + * Returns:
> > + * On success, 1 for on and 0 for off; negative error number on failure.
> > + */
> > +int pwrseq_power_is_on(struct pwrseq_desc *desc)
> > +{
> > +     if (!desc)
> > +             return -EINVAL;
> > +
> > +     return desc->powered_on;
> > +}
> > +EXPORT_SYMBOL_GPL(pwrseq_power_is_on);
> > +
>
> Didn't we agree on introducing an enum to make it future-proof for when we
> also pull in pwrseq_is_controllable() from Loic?

My bad. I misunderstood and thought it wasn't needed yet.

> I think this should work like so:
>
> enum {
>         PWRSEQ_STATE_UNKNOWN,
>         PWRSEQ_STATE_ON,
>         PWRSEQ_STATE_OFF,
> };
>
> int pwrseq_get_state(struct pwrseq_desc *desc)
> {

I think you still want this here?

          if (!desc)
                    return -EINVAL;


>         /* Only once this is upstream. */
>         if (!pwrseq_is_controllable(desc))
>                 return PWRSEQ_STATE_UNKNOWN;
>
>         return desc->powred_on ? PWRSEQ_STATE_ON : PWRSEQ_STATE_OFF;
> }
>
> Bart


Thanks
ChenYu