On Thu, Aug 18, 2016 at 4:30 PM, Suman Anna [off-list ref] wrote:

Hi Rob,

On 08/16/2016 09:54 AM, Rob Herring wrote:

quoted

On Fri, Aug 12, 2016 at 11:43 AM, Bjorn Andersson
[off-list ref] wrote:

quoted

On Fri 12 Aug 09:00 PDT 2016, Suman Anna wrote:

quoted

On 08/12/2016 06:02 AM, Lee Jones wrote:

quoted

On Thu, 11 Aug 2016, Suman Anna wrote:

[...]

quoted

quoted

quoted

Once "rprocs" hits mainline, I will definitely switch over the
wkup_m3_ipc nodes to use that standard property and can fix this driver
independently.

We're stuck with this problem all over the place, as the world continues
to evolve we will have issues with DT being static. This has been
discussed many times before and the suggested solution is always what
you implemented here - make the code deal with both versions, preferably
by patching.

The fact that you had to export the of_ operations indicates that no-one
has tried this before and I'm happy you did. I'm however not happy about
the size of the chunk of code it takes to do this dance.

I think for this to be practical we need to provide higher level
operations for DT modification - in this case a of_rename_property().

@Rob, any comments on this?

I agree. Pantelis submitted some helpers in this area a while back
(for the changeset API IIRC). I believe they were mostly fine, but
needed some users.

Is this the series you are talking about?
http://marc.info/?l=devicetree&m=146341689512653&w=2

It looks like that series is effective only when OF_DYNAMIC is enabled.

Yes, as changeset API allows adding/removing nodes. It's probably just
a matter of time until OF_DYNAMIC is always enabled.

Probably a dumb question, but is this limited to DT Overlays?

No, changesets are the mechanism overlays use to apply changes.

This
particular usage is a one-time change (first-time module is insmod'd)
mainly to provide compatibility for older DTBs, thereafter we wouldn't
be required to make any changes. It is definitely not a bulk update and
we don't want to unroll the changes even if we removed the module.

If you only need property changes, then we could do similar helpers to
make it easier for callers.

Rob