Re: [RFC PATCH 1/2] ACPI / PNP: Don't add "enumeration_by_parent" devices

[John Garry]

> > > > So we using the mfd_cell to match child devices using _HID. At a glance, I
> > > > don't actually see other drivers to use mfd_cell_acpi_match.pnpid .
> > > >
> > > > Anyway we don't use static tables as we need to update the resources of the
> > > > cell dynamically. However I do look at a driver like intel_quark_i2c_gpio.c,
> > > > and this dynamically modifies the value of global mfd_cell array here:
> > > > https://elixir.bootlin.com/linux/latest/source/drivers/mfd/intel_quark_i2c_gpio.c#L266
> > > >
> > > > I know the cell array is only used at probe time, but this did not look to
> > > > be good standard practice to me.
> > >
> > > Lots of drivers do this to supply dynamic data.  If there is no other
> > > sane way of providing such data, it's fine to do.  Although each
> > > situation should be dealt with on a case-by-case basis.
> >
> > Hi Lee,
> >
> > Thanks for your input.
> >
> > I do see others drivers which use dynamic mem for the mfd_cells (like
> > cros_ec_dev.c), so what we're doing in this driver already is not totally
> > unchartered territory. But creating the MFD cells from the ACPI table could
> > be ...
>
> Right.  I don't normally like mixing platform data technologies (MFD,
> ACPI and DT).  I normally NACK patches which take information from
> Device Tree and populate MFD cells with it.  ACPI would be the same I
> guess.

Oh, well that is what we have in this driver. So what's the preferred 
approach? Just not use MFD model at all if ACPI/DT needs to be scanned 
for data to create the cells?

Thanks,
John

> > Anyway, I'll cc you in my next patchset and maybe you can kindly check it.