[SPAM]Re: [PATCH v3 4/5] dt-bindings: clock: mediatek: update audsys documentation to adapt MFD device

[ryder.lee@mediatek.com (Ryder Lee)]

On Wed, 2018-02-21 at 08:10 -0600, Rob Herring wrote:
> On Wed, Feb 21, 2018 at 12:04 AM, Ryder Lee <ryder.lee@mediatek.com> wrote:
> > On Mon, 2018-02-19 at 12:29 -0600, Rob Herring wrote:
> >> On Mon, Feb 12, 2018 at 5:28 AM, Ryder Lee <ryder.lee@mediatek.com> wrote:
> >> > The MediaTek audio hardware block that exposes functionalities that are
> >> > handled by separate subsystems in the kernel.  These functions are all
> >> > mapped somewhere at 0x112xxxxx, and there are some control bits are mixed
> >> > up with other functions within the same registers.
> >>
> >> I still don't think this change is necessary.
> >>
> >> Just because a hardware block in DT maps to different subsystems in a
> >> particular OS doesn't mean you need a DT node for each OS subsystem.
> >> What we have subsystems for changes over time and DT shouldn't really
> >> be changing based on that. And DT is not the only way to instantiate
> >> drivers.
> >>
> >
> > Apart right now we have the definition of both functions. The other
> > location is here:../sonud/mt2701-afe-pcm.txt. The ways I could come up
> > with are:
> 
> There are several problems you need to fix. First,
> "mediatek,mt2701-audsys" is not documented. It is only used in the
> example. Second, bindings/arm/mediatek/mediatek,audsys.txt should move
> to bindings/sound/ if it is only audio related functions. Or perhaps
> just combine the 2 documents because it is all inconsistent currently.

Because the series crossed subsystems but didn't apply at the same time.

> The 2 documents are inconsistent as to what is the relationship of
> -audsys and -audio (afe) nodes. mt2701-afe-pcm.txt shows that the AFE
> is already a child of -audsys. The -audsys node should have
> #clock-cells. It should also not be a simple-mfd (another
> inconsistency in the binding) because it needs to probe first to
> provide clocks to child nodes, and then trigger probing the child
> nodes.

This is the 1st version I sent before, and the clock parts still under
review :( .  But yes, the 2 inconsistent documents should be fixed -
this may depend on what we end up doing with the DT appearance.

IMHO, apart from overlapping regions with other functions I didn't see
any difference between audsys and other clock drivers (providers).

For the sake of uniformity, I make the 2 sub-devices parallel and move
"simple-mfd" to the top, and the sequences should actually be handled
through "probe deferral mechanism" - that would make this kind of
situations much easier to manage.

BTW, I could make the AFE driver be instantiated/probed from the clock
driver but this seems superfluous to me.  Just make sure is this what
you want?

Ryder