Re: [PATCH v7 06/13] pwm: add support for sl28cpld PWM controller

[Michael Walle]

Am 2020-08-10 09:13, schrieb Lee Jones:
> On Fri, 07 Aug 2020, Michael Walle wrote:
>
> > Hi Uwe, Hi Lee,
> >
> > Am 2020-08-06 10:40, schrieb Uwe Kleine-König:
> > > On Mon, Aug 03, 2020 at 11:35:52AM +0200, Michael Walle wrote:
> > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> > > > index 7dbcf6973d33..a0d50d70c3b9 100644
> > > > --- a/drivers/pwm/Kconfig
> > > > +++ b/drivers/pwm/Kconfig
> > > > @@ -428,6 +428,16 @@ config PWM_SIFIVE
> > > >  	  To compile this driver as a module, choose M here: the module
> > > >  	  will be called pwm-sifive.
> > > >
> > > > +config PWM_SL28CPLD
> > > > +	tristate "Kontron sl28cpld PWM support"
> > > > +	select MFD_SIMPLE_MFD_I2C
> > >
> > > Is it sensible to present this option to everyone? Maybe
> > >
> > > 	depends on SOME_SYMBOL_ONLY_TRUE_ON_SL28CPLD || COMPILE_TEST
> >
> > Because there is now no real MFD driver anymore, there is also
> > no symbol for that. The closest would be ARCH_ARM64 but I don't
> > think that is a good idea.
> >
> > Lee, what do you think about adding a symbol to the MFD, which
> > selects MFD_SIMPLE_MFD_I2C but doesn't enable any C modules?
> >
> > I.e.
> > config MFD_SL28CPLD
> >     tristate "Kontron sl28cpld"
> >     select MFD_SIMPLE_MFD_I2C
> >     help
> >       Say yes here to add support for the Kontron sl28cpld board
> >       management controller.
> >
> > Then all the other device driver could depend on the MFD_SL28CPLD
> > symbol.
>
> You want to add a virtual symbol to prevent having to present a real
> one?  How is that a reasonable solution?

(1) Its a symbol on which all sl28cpld will depend on. Thus they will
    all be hidden if that is not set.
(2) the drivers itself wouldn't need to depend on MFD_SIMPLE_MFD_I2C,
    which is more correct, because they don't have anything to do with
    i2c.

-michael