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

[Matti Vaittinen]

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!
> >
> > > ---
> > >    MAINTAINERS                  |   2 +
> > >    drivers/mfd/Kconfig          |   6 ++
> > >    drivers/mfd/Makefile         |   1 +
> > >    drivers/mfd/rohm-bd71828.c   |  84 ++------------------------
> > >    drivers/mfd/rohm-bd718x7.c   |  84 ++------------------------
> > >    drivers/mfd/rohm-pwrbutton.c | 112 +++++++++++++++++++++++++++++++++++
> > >    drivers/mfd/rohm-pwrbutton.h |  12 ++++
> > >    7 files changed, 141 insertions(+), 160 deletions(-)
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index f1caa6e5198b..40c46a7363fb 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -23524,6 +23524,8 @@ F:	drivers/mfd/rohm-bd71828.c
> > >    F:	drivers/mfd/rohm-bd718x7.c
> > >    F:	drivers/mfd/rohm-bd9576.c
> > >    F:	drivers/mfd/rohm-bd96801.c
> > > +F:	drivers/mfd/rohm-pwrbutton.c
> > > +F:	drivers/mfd/rohm-pwrbutton.h
> > >    F:	drivers/regulator/bd71815-regulator.c
> > >    F:	drivers/regulator/bd71828-regulator.c
> > >    F:	drivers/regulator/bd718x7-regulator.c
> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > index 763ce6a34782..8d04e1b1f8c8 100644
> > > --- a/drivers/mfd/Kconfig
> > > +++ b/drivers/mfd/Kconfig
> > > @@ -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(?)

Well, I am not going to insist - I feel like you're already going an 
extra mile with this - but I really believe more generic helper would be 
useful :)

Yours,
	-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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