doc: release notes: Mention devicetree script changes for 2.0 and 2.1

Added in 2.0, along with some binding format simplifications in 2.1.

Bunch of other stuff that could be mentioned, but keep it relatively
short.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>

doc/guides/dts/index.rst

@@ -449,6 +449,71 @@ Below is a template that shows the format of binding files, stored in
 .. literalinclude:: ../../../dts/binding-template.yaml
    :language: yaml
 
+.. _legacy_binding_syntax:
+
+Legacy binding syntax
+=====================
+
+Various parts of the binding syntax were simplified and generalized for the
+Zephyr 2.1 release.
+
+The binding below shows various legacy syntax.
+
+.. code-block:: yaml
+
+   title: ...
+   description: ...
+
+   inherits:
+       !include foo.yaml
+
+   parent:
+       bus: spi
+
+   properties:
+       compatible:
+           constraint: "company,device"
+           type: string-array
+
+       frequency:
+           type: int
+           category: optional
+
+   sub-node:
+       properties:
+           child-prop:
+               type: int
+               category: required
+
+This should now be written like this:
+
+.. code-block:: yaml
+
+   title: ...
+   description: ...
+
+   compatible: "company,device"
+
+   include: foo.yaml
+
+   parent-bus: spi
+
+   properties:
+       frequency:
+           type: int
+           required: false
+
+   child-node:
+       title: ...
+       description: ...
+
+       properties:
+           child-prop:
+               type: int
+               required: true
+
+The legacy syntax is still supported for backwards compatibility, but generates
+deprecation warnings. Support will be dropped in the Zephyr 2.3 release.
 
 Include files generation
 ************************

doc/releases/release-notes-2.0.rst

@@ -448,6 +448,27 @@ Bluetooth
 Build and Infrastructure
 ************************
 
+* The devicetree Python scripts have been rewritten to be more robust and
+  easier to understand and change. The new scripts are these three files:
+
+  - :zephyr_file:`scripts/dts/dtlib.py` -- a low-level :file:`.dts` parsing
+    library
+
+  - :zephyr_file:`scripts/dts/edtlib.py` -- a higher-level library that adds
+    information from bindings
+
+  - :zephyr_file:`scripts/dts/gen_defines.py` -- generates a C header from the
+    devicetree files for the board
+
+  The new scripts verify ``category: optional/required`` and ``type:`` settings
+  given in bindings for nodes, and add some new types, like ``phandle-array``.
+  Error messages and other output is now more helpful.
+
+  See the updated documentation in :zephyr_file:`dts/binding-template.yaml`.
+
+  The old scripts are kept around to generate a few deprecated ``#define``\ s.
+  They will be removed in the Zephyr 2.2 release.
+
 * Changed ARM Embedded toolchain to default to nano variant of newlib
 
 

doc/releases/release-notes-2.1.rst

@@ -50,6 +50,11 @@ Build and Infrastructure
   Use new functions that utilize eDTS info such as dt_node_reg_addr.
   See :zephyr_file:`scripts/kconfig/kconfigfunctions.py` for details.
 
+* Various parts of the binding format have been simplified. The format is
+  better documented now too.
+
+  See :ref:`legacy_binding_syntax` for more information.
+
 Libraries / Subsystems
 ***********************