On Mon, Aug 18, 2025 at 09:56:07AM +0300, Matti Vaittinen wrote:
> On 18/08/2025 09:54, Matti Vaittinen wrote:
> > On 18/08/2025 01:47, Dmitry Torokhov wrote:
> > > Refactor the rohm-bd71828 MFD driver to use software nodes for
> > > instantiating the gpio-keys child device, replacing the old
> > > platform_data mechanism.
> >
> > Thanks for doing this Dmitry! I believe I didn't understand how
> > providing the IRQs via swnode works... :)
> >
> > If I visit the ROHM office this week, then I will try to test this using
> > the PMIC HW. (Next week I'll be in ELCE, and after it I have probably
> > already forgotten this...)
> >
> > > The power key's properties are now defined using software nodes and
> > > property entries. The IRQ is passed as a resource attached to the
> > > platform device.
> > >
> > > This will allow dropping support for using platform data for configuring
> > > gpio-keys in the future.
> > >
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> > > ---
> > > drivers/mfd/rohm-bd71828.c | 81 +++++++++++++++++++++++++++-----------
> > > 1 file changed, 58 insertions(+), 23 deletions(-)
> > >
> > > diff --git a/drivers/mfd/rohm-bd71828.c b/drivers/mfd/rohm-bd71828.c
> > > index a14b7aa69c3c..c29dde9996b7 100644
> > > --- a/drivers/mfd/rohm-bd71828.c
> > > +++ b/drivers/mfd/rohm-bd71828.c
> > > @@ -4,7 +4,6 @@
> >
> > // ...snip
> >
> > > +static int bd71828_reg_cnt;
> > > +
> > > +static int bd71828_i2c_register_swnodes(void)
> > > +{
> > > + int error;
> > > +
> > > + if (bd71828_reg_cnt == 0) {
> >
> > Isn't this check racy...
> >
> > > + error = software_node_register_node_group(bd71828_swnodes);
> > > + if (error)
> > > + return error;
> > > + }
> > > +
> > > + bd71828_reg_cnt++;
> >
> > ... with this...
> >
> > > + return 0;
> > > +}
> > > +
> > > +static void bd71828_i2c_unregister_swnodes(void *dummy)
> > > +{
> > > + if (bd71828_reg_cnt != 0) {
> >
> > ...this...
> >
> > > + software_node_unregister_node_group(bd71828_swnodes);
> > > + bd71828_reg_cnt--;
> >
> > ...and this? Perhaps add a mutex or use atomics?
> >
> > Also, shouldn't the software_node_unregister_node_group() be only called
> > for the last instance to exit (Eg, "if (bd71828_reg_cnt == 0)" instead
> > of the "if (bd71828_reg_cnt != 0) {")?
>
> Oh. Probably "if (bd71828_reg_cnt == 1)".
You are right, I am not sure what I was thinking when I wrote this.
I actually doubt that sharing of nodes between devices would work well.
But I believe these devices are singletons, it should not be possible to
have several of them in a single system, right? So maybe the best way is
to simply instantiate them in probe and bail out if they are already
registered.
Thanks.
--
Dmitry
