Re: [PATCH] mfd: rohm: Factor out power button registration

[Matti Vaittinen]

ti 7.7.2026 klo 1.27 Dmitry Torokhov (dmitry.torokhov@xxxxxxxxx) kirjoitti:
>
> Hi Matti,
>
> On Fri, Jun 26, 2026 at 10:35:19AM +0300, Matti Vaittinen wrote:
> > On 25/06/2026 21:33, Dmitry Torokhov wrote:
> > > Hi Matti,
> > >
> > > On Thu, Jun 25, 2026 at 11:00:08AM +0300, Matti Vaittinen wrote:
> > > > On 18/06/2026 21:58, Dmitry Torokhov wrote:
> > > > > Factor out the power button registration logic using software nodes
> > > > > from rohm-bd718x7 and rohm-bd71828 drivers into a shared module
> > > > > rohm-pwrbutton.
> > > > >
> > > > > This reduces duplication and makes it easier to support other ROHM
> > > > > PMICs with similar power button configurations.
> > > > >
> > > > > Suggested-by: Lee Jones <lee@xxxxxxxxxx>
> > > > > Assisted-by: Antigravity:gemini-3.5-flash
> > > > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> > > >
> > > > Thanks a lot Dmitry. I like the idea of having generic helpers for crearting
> > > > the swnodes for the power-button!
> > > >
> > > > > ---

> > > > > @@ -2208,6 +2208,10 @@ config MFD_STW481X
> > > > >           in various ST Microelectronics and ST-Ericsson embedded
> > > > >           Nomadik series.
> > > > > +config MFD_ROHM_PWRBUTTON
> > > > > +       tristate
> > > > > +       select MFD_CORE
> > > >
> > > > I would drop the MFD dependency from the helper. It'd be nice to be able to
> > > > add the SW-nodes representing power-button(s) outside MFD as well.
> > >
> > > Do you have potential users in mind for this? I mean specifically
> > > single IRQ-backed buttons besides these 2 ROHM controllers?
> >
> > I don't think it needs to be a single IRQ backed? There are quite a few IRQs
> > in these PMICs. But no, I don't have concrete users for you (as of now), but
> > a power-button which generates and IRQ does really sound like a very generic
> > concept to me.
> >
> > > I would prefer no over-generalize if there are no users. Kernel modules
> > > are not totally free.
> >
> > I suppose these IRQ backed power-buttons would in most cases be handled by
> > the GPIO_KEYS. Perhaps you could consider exporting the helper from it
> > instead of having it in MFD(?)
>
> I want through drivers for similar buttons and I currently do not see
> any other candidates for the conversion besides the 2 ROHM drivers. This
> is because the rest of the power button drivers implement true tracking
> of the button state (instead of only detecting press via an IRQ and
> simulating release).
>
> The only potential users of the helper would be new drivers, but new
> drivers outside of MFD realm will use ACPI/DT

Probably true.

 and not static device
> properties as they will handle new devices on new boards. It is only
> within the context of MFD that I can see slight possibility of more
> drivers using this mechanism (and not regular DT configuration) and that
> is why I do not think putting the helper in gpio-keys would make sense.
>
> Additionally putting it in gpio-keys will add unwanted (IMO) dependency
> (module-load-wise).

Ok. Thanks for the explanation.

Yours,
    -- Matti

-- 

Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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