On Fri, Jan 02, 2026 at 06:06:51PM +0100, Bartosz Golaszewski wrote:
> On Fri, Jan 2, 2026 at 4:10 PM Dmitry Baryshkov
> <[email protected]> wrote:
> >
> > On Fri, 2 Jan 2026 at 13:07, Bartosz Golaszewski <[email protected]> wrote:
> > >
> > > On Wed, Dec 31, 2025 at 12:36 AM Dmitry Baryshkov
> > > <[email protected]> wrote:
> > > >
> > > > The WCN39xx family of WiFi/BT chips incorporates a simple PMU, spreading
> > > > voltages over internal rails. Implement support for using powersequencer
> > > > for this family of ATH10k devices in addition to using regulators.
> > > >
> > > > Signed-off-by: Dmitry Baryshkov <[email protected]>
> > > > ---
> > >
> > > [snip]
> > >
> > > >
> > > >  static void ath10k_snoc_wlan_disable(struct ath10k *ar)
> > > > @@ -1762,7 +1779,27 @@ static int ath10k_snoc_probe(struct 
> > > > platform_device *pdev)
> > > >                 goto err_release_resource;
> > > >         }
> > > >
> > > > -       ar_snoc->num_vregs = ARRAY_SIZE(ath10k_regulators);
> > > > +       /*
> > > > +        * Backwards compatibility, ignore the defer error from pwrseq, 
> > > > if it
> > > > +        * should be used, we will get an error from regulator get.
> > > > +        */
> > >
> > > Can you elaborate on this? I'm not exactly following. I suppose you
> > > mean the regulator_get() will return -EPROBE_DEFER? One of the
> > > supplies exposed by the PMU?
> >
> > Yes. devm_pwrseq_get() can return -EPROBE_DEFER in two cases:
> > - it is not supposed to be used
> > - it is supposed to be used, but the driver hasn't probed yet.
> >
> 
> Yes but normally driver core would still create a devlink between the
> device binding to the PMU node and the consumer of its regulators -

fw_devlink, which are not mandatory, time out, etc. So, no, it is not
granted that the PMU is always available during the probe.

> this device - so we can expect that it will always be the first one,
> no? Unless we need this driver to be firmware-agnostic.
> 
> > There is no simple way to distinguish between these two cases, but:
> > - if it is not supposed to be used, then regulator_bulk_get() will
> > return all regulators as expected, continuing the probe
> > - if it is supposed to be used, but wasn't probed yet, we will get
> > -EPROBE_DEFER from regulator_bulk_get() too.
> >
> > I can write that in a comment, if you think that it makes the code more 
> > obvious.
> >
> 
> Yes, please make it more descriptive. Ideally I'd like to improve the
> API to avoid such confusion in the future.

The prolem is that we can't (or I don't see a way to). Power sequencing
core has no way to distinguish these two cases.

-- 
With best wishes
Dmitry

Reply via email to