On Wed, Feb 21, 2018 at 12:04 AM, Ryder Lee [off-list ref] wrote:

On Mon, 2018-02-19 at 12:29 -0600, Rob Herring wrote:

quoted

On Mon, Feb 12, 2018 at 5:28 AM, Ryder Lee [off-list ref] wrote:

quoted

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.

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.

Rob

1. Add a dummy MFD driver (need to think a new compatible or just use
'*-audsys' which has already been picked by clock driver) to instantiate
two sub-devices through id_table and mfd_cell.

2. For the sake of simplification - add a new compatible "simple-mfd".

3. The last thing - keep two nodes separated/independent. (x)

I'm not sure which one is better.



@Lee @Matthias: What do you suggest?

Ryder.