Re: [PATCH] HISI LPC: Add Kconfig MFD_CORE dependency

[John Garry]

On 19/04/2018 14:29, Arnd Bergmann wrote:
> On Thu, Apr 19, 2018 at 3:08 PM, John Garry <john.garry@xxxxxxxxxx> wrote:
> > On 19/04/2018 13:00, Arnd Bergmann wrote:
> > > On Thu, Apr 19, 2018 at 1:55 PM, John Garry <john.garry@xxxxxxxxxx> wrote:
> > > > For ACPI support of the HiSilicon LPC driver we depend
> > > > on MFD_CORE config.
> > > >
> > > > Currently the HiSi LPC Kconfig entry does not define this
> > > > dependency, so add it.
> > > >
> > > > Fixes: e0aa1563f894 ("HISI LPC: Add ACPI support")
> > > > Reported-and-tested-by: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>
> > > > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> > >
> > >
> > > Can you explain the specific dependency? Normally MFD_CORE gets
> > > selected by an MFD driver but not other drivers.
> >
> > For each device on the LPC bus we create an MFD.
> >
> > The reason we do this is that we need to set the resources of the derived
> > MFD, as we should not modify the original ACPI device created in ACPI scan.
> > Details are in the log for e0aa1563f894.
> >
> > Shall I update commit message updated with this info? Or were you just
> > interested in the motivation for using MFD?
>
> I think it would be good to update the description. I had missed the part
> where an LPC device becomes a platform_device through an mfd_cell
> rather than becoming a device with bus_type=&isa_bus_type as I think
> was the case in earlier versions of your patch series.

OK, fine. FYI, this was originally discussed here: 
https://lkml.org/lkml/2017/6/13/602

BTW, as for merging patches for this driver, it would seem the right 
place for it to go through arm/soc tree (obviously depending on 
dependencies). Since xuwei is away this week, could you kindly pick up 
v2 for fixes?

Thanks,
John


>      Arnd
>
> .