Hi,

On Mon, May 11, 2020 at 09:55:11AM -0500, Dan Murphy wrote:
> On 5/11/20 9:57 AM, Sebastian Reichel wrote:
> > On Mon, May 11, 2020 at 09:29:59AM -0500, Dan Murphy wrote:
> > > On 5/11/20 9:32 AM, Sebastian Reichel wrote:
> > > > On Mon, May 11, 2020 at 07:25:06AM -0500, Dan Murphy wrote:
> > > > > On 5/10/20 11:17 AM, Sebastian Reichel wrote:
> > > > > > This needs is missing the power-supplies property. The N900 DT
> > > > > > contains a bq27200 referencing the charger, so it should fail the DT
> > > > > > check without the property being listed here.
> > > > > Hmm.  I ran the dt checker specifically on the binding and it did not fail.
> > > > > Unless I need to build some other DTs as well.
> > > > > Either I will have the power-supplies property
> > > > I just tried it myself. The problem is the way you are specifying
> > > > the compatible strings. This is the parsing result:
> > > > 
> > > > enum: ['ti,bq27200 - BQ27200', 'ti,bq27210 - BQ27210', 'ti,bq27500 - deprecated,
> > > >         use revision specific property below', ...
> > > > 
> > > > You can see this in Documentation/devicetree/bindings/processed-schema.yaml, which
> > > > is generated by running the check. The compatible comments need a # as separation
> > > > character like this to generate proper bindings:
> > > > 
> > > > properties:
> > > >     compatible:
> > > >       enum:
> > > >         - ti,bq27200 # BQ27200
> > > >         - ti,bq27210 # BQ27210
> > > >         - ti,bq27500 # deprecated, use revision specific property below
> > > Well honestly not sure why we need the comment either. These are pretty
> > > self explanatory maybe we should just remove the additional comments
> > Fine with me.
> Ack
> > 
> > > Any consideration on just removing the deprecated values?
> > Let's keep them with their comment for now. Removing them should
> > start with marking them as depracated in the binding and generating
> > a runtime warning in the driver, so that people become aware of the
> > problem. At least for ti,bq27500 we have mainline users At least for
> > ti,bq27500 we have mainline users.
> 
> There are only 2 dts files that have this reference unless we are not sure
> which device is actually in use.

DT is considered ABI and one is supposed to be able to boot a new
kernel with an old DT. It's not enough to just update the in-tree
dts files. I suppose we can consider removing support for the old
compatible values after having the warning being printed for some
time and the mainline users being converted to the new binding.

-- Sebastian