Re: [PATCH v3 07/15] devicetree: Add DeviceTree live tree representation

[Simon Glass]

Hi,

On Tue, 10 Nov 2026 at 21:16, David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Nov 06, 2026 at 06:43:18PM -0800, Doug Anderson wrote:
> > Hi Simon,
> >
> > On Wed, Nov 4, 2026 at 6:08 AM Simon Glass <sjg@xxxxxxxxxxxx> wrote:
> > >
> > > Hi Doug,
> > >
> > > On Sun, Nov 1, 2026 at 4:02 PM Douglas Anderson <dianders@xxxxxxxxxxxx> wrote:
> > > >
> > > > Add `devicetree.py` providing `DeviceTree`, a non-flattened in-memory
> > > > representation of a devicetree node and its subtree:
> > >
> > > Please can you start with the motivation, i.e. why a live tree is
> > > needed and what will use it? The list below mostly repeats the
> > > docstrings.
> >
> > Makes sense. In my draft v4 I've updated the commit message to lead
> > with the motivation and condensed the summary so it doesn't repeat the
> > docstrings:
> >
> >     `pylibfdt`'s `Fdt` and `FdtRo` classes operate directly on flattened
> >     device tree blobs, where inserting or deleting nodes and properties
> >     shifts subsequent node offsets. That works well for in-place queries and
> >     localized edits, but makes multi-tree comparison, structural diffing,
> >     and bottom-up tree construction (as needed by the upcoming `fdtfactor`
> >     tool) awkward and error-prone.
> >
> >     Add `pylibfdt/devicetree.py` providing `DeviceTree`, an in-memory live
> >     tree representation where each node holds `props` (a dict mapping
> >     property name to `libfdt.Property`) and `children` (a dict mapping child
> >     node name to child `DeviceTree`), along with `unflatten()` and
> >     `flatten()` to convert between `FdtRo`/`Fdt` blobs and live trees, and
> >     helpers for path lookup, node creation, and pre-order traversal.
> >
> >     Add unit tests in `tests/devicetree_tests.py` covering `DeviceTree`
> >     round-tripping, subtree unflattening, duplicate-name and corrupt-tree
> >     rejection, and navigation helpers.
> >
> > > > diff --git a/devicetree.py b/devicetree.py
> > > > new file mode 100644
> > > > index 0000000..f81b8fc
> > > > --- /dev/null
> > > > +++ b/devicetree.py
> > > > @@ -0,0 +1,226 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
> > > > +"""devicetree - Non-flattened in-memory device tree representation in Python."""
> > >
> > > I'd forgotten about this but PyPI has Zephyr's python-devicetree
> > > [1][2], which installs a top-level 'devicetree' package.
> > >
> > > I'm not sure what to suggest. Would libfdt_devicetree be too awful?
> >
> > Right. I'm OK with libfdt_devicetree. David: do you have any
> > objections?
>
> Don't love it, but can't quickly think of a better option.

Would libfdt_tree be better?

BTW we might be able to change pylibfdt to package (and even call it
libfdt on PyPi), iwc perhaps libfdt.devicetree might make sense, down
the track.

Regards,
Simon