[v4,1/2] cpufreq: tegra124: Remove use of disable_cpufreq

From: Aaron Kling <webgeek1234@gmail.com>

Instead, unregister the cpufreq device for this fatal fail case.

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 drivers/cpufreq/tegra124-cpufreq.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

On Fri, May 9, 2025 at 6:04 AM Jon Hunter <jonathanh@nvidia.com> wrote:
>
>
>
> On 09/05/2025 01:04, Aaron Kling via B4 Relay wrote:
> > From: Aaron Kling <webgeek1234@gmail.com>
> >
> > Instead, unregister the cpufreq device for this fatal fail case.
>
> This is not a complete sentence. Seems to be a continuation of the
> subject which is not clear to the reader (at least not to me). No
> mention of why or what this is fixing, if anything?

I can clean up the subject and message in a new revision. More on the
reasoning below.

> >
> > Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> > ---
> >   drivers/cpufreq/tegra124-cpufreq.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> > index 514146d98bca2d8aa59980a14dff3487cd8045f6..bc0691e8971f9454def37f489e4a3e244100b9f4 100644
> > --- a/drivers/cpufreq/tegra124-cpufreq.c
> > +++ b/drivers/cpufreq/tegra124-cpufreq.c
> > @@ -168,7 +168,10 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
> >   disable_dfll:
> >       clk_disable_unprepare(priv->dfll_clk);
> >   disable_cpufreq:
> > -     disable_cpufreq();
> > +     if (!IS_ERR(priv->cpufreq_dt_pdev)) {
> > +             platform_device_unregister(priv->cpufreq_dt_pdev);
> > +             priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
> > +     }
>
> So you are proposing to unregister the device in resume? That seems odd.
> I see there is no remove for this driver, but I really don't see the
> value in this.

This was suggested by Viresh in v1 [0] to replace the call to
disable_cpufreq, which is not currently an exported function. I'm open
to other suggestions.

Sincerely,
Aaron

[0] https://lore.kernel.org/all/20250421054452.fdlrrhtsimyucbup@vireshk-i7/

On Fri, May 9, 2025 at 11:57 AM Aaron Kling <webgeek1234@gmail.com> wrote:
>
> On Fri, May 9, 2025 at 6:04 AM Jon Hunter <jonathanh@nvidia.com> wrote:
> >
> >
> >
> > On 09/05/2025 01:04, Aaron Kling via B4 Relay wrote:
> > > From: Aaron Kling <webgeek1234@gmail.com>
> > >
> > > Instead, unregister the cpufreq device for this fatal fail case.
> >
> > This is not a complete sentence. Seems to be a continuation of the
> > subject which is not clear to the reader (at least not to me). No
> > mention of why or what this is fixing, if anything?
>
> I can clean up the subject and message in a new revision. More on the
> reasoning below.
>
> > >
> > > Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> > > ---
> > >   drivers/cpufreq/tegra124-cpufreq.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> > > index 514146d98bca2d8aa59980a14dff3487cd8045f6..bc0691e8971f9454def37f489e4a3e244100b9f4 100644
> > > --- a/drivers/cpufreq/tegra124-cpufreq.c
> > > +++ b/drivers/cpufreq/tegra124-cpufreq.c
> > > @@ -168,7 +168,10 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
> > >   disable_dfll:
> > >       clk_disable_unprepare(priv->dfll_clk);
> > >   disable_cpufreq:
> > > -     disable_cpufreq();
> > > +     if (!IS_ERR(priv->cpufreq_dt_pdev)) {
> > > +             platform_device_unregister(priv->cpufreq_dt_pdev);
> > > +             priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
> > > +     }
> >
> > So you are proposing to unregister the device in resume? That seems odd.
> > I see there is no remove for this driver, but I really don't see the
> > value in this.
>
> This was suggested by Viresh in v1 [0] to replace the call to
> disable_cpufreq, which is not currently an exported function. I'm open
> to other suggestions.
>
> Sincerely,
> Aaron
>
> [0] https://lore.kernel.org/all/20250421054452.fdlrrhtsimyucbup@vireshk-i7/

Viresh, could you comment here please? As you were the one that
suggested replacing disable_cpufreq with an unregister instead of
exporting said function. I can make the code changes and verify they
work as intended, but I'm not familiar enough with this subsystem to
know what a good option here is. Are there any other cpufreq drivers
that have to handle a resume failure like this?

Sincerely,
Aaron

On Tue, May 20, 2025 at 5:02 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 20-05-25, 10:53, Jon Hunter wrote:
> > I understand, but this seems odd. It would be odd that the device may just
> > disappear after resuming from suspend if it fails to resume. I have not seen
> > this done for other drivers that fail to resume. Presumably this is not the
> > only CPU Freq driver that could fail to resume either?
> >
> > It makes the code messy because now we have more than one place where the
> > device could be unregistered.
>
> Fair enough.
>
> This driver, along with other cpufreq drivers, can fail at multiple
> places during suspend/resume (and other operations). If something goes
> wrong, we print an error to inform the user. Should we avoid doing
> anything else (like everyone else) ? i.e. Just remove the call to
> disable_cpufreq(), as all later calls will fail anyway.
>
> This is the only driver that behaves differently on failures.
>
> --
> viresh

Is there any consensus on the best way to handle this? I'd like to
keep the series moving.

Sincerely,
Aaron