[PATCH 0/6] Ancillary bus implementation and SOF multi-client support

[Jason Gunthorpe]

On Thu, Oct 01, 2020 at 05:51:37PM +0100, Mark Brown wrote:
> On Thu, Oct 01, 2020 at 11:20:39AM -0500, Pierre-Louis Bossart wrote:
> 
> > I have nothing against MFD, but if this boils down to platform devices we
> > are back to the initial open "are platform devices suitable as children of
> > PCI devices"? I've heard Greg say no for the last year and a half - and he
> > just re-stated this earlier in this thread.
> 
> As you'll have seen from this thread and the prior version (which was
> the first time I became aware of this stuff) I'm not clear how that
> desire maps on to hardware, as soon as subdevices start needing to get
> regions and interrupts mapped then we're going to end up reinventing
> resources and regmaps AFAICT.

I think the truth is MFD and anciallary bus are solving almost the
same problem and could meet in the middle at some point.

Since Greg has completely NAK'd using pci_device inside MFD it looks
like this is the preference.

If people have a use case for regmaps/IRQs then they should add them
here. Right now the places I know of don't need this.

The target for this is queue-based devices where the sharing granule
is a queue. The actual thing being shared to the subsystem from the
PCI driver basically the ability to create a queue.

Jason