scripts: dts: fix CMake DT API helper for compatible properties

Our build system DT API has a dt_comp_path() function used to look up
paths of nodes with a given compatible. This relies on the generated
edt.pickle.cmake file in the build directory to look inside the
concrete devicetree for the current application build.

The script gen_dts_cmake.py is responsible for generating
edt.pickle.cmake. It currently generates the data needed by
dt_comp_path() by looking inside each edtlib.Node object's "props"
attribute. This attribute in turn is fed by the "properties:" key in
the node's YAML binding. This leads to an edge case which is breaking
the dt_comp_path() API.

In most cases, we don't notice this edge case because base.yaml, which
is included by nearly all bindings, has a definition for "compatible"
in its "properties:" map. However, bindings are not required to
include base.yaml, and bindings do not have to explicitliy define a
"compatible" entry in their "properties:". An example of a binding
that does neither is fixed-partitions.yaml: it only has #address-cells
and #size-cells in its "properties:".

Nonetheless, "compatible:" is always a valid property name because
it's defined in the DT spec, and we should make the CMake API robustly
detect all nodes with a given compatible, regardless of whether that
node's binding explicitly defines it or not.

To make this happen, rely on the edtlib.Node.compats attribute instead
of edtlib.Node.props. The compats attribute is always defined even if
the node's YAML binding doesn't have an explicit entry for
"compatible".

Signed-off-by: Martí Bolívar <[email protected]>

Author: mbolivar

scripts/dts/gen_dts_cmake.py

@@ -134,10 +134,8 @@ def main():
                 cmake_prop = f'DT_PROP|{node.path}|{item}'
                 cmake_props.append(f'"{cmake_prop}" "{escape(cmake_value)}"')
 
-                if item == 'compatible':
-                    # compatibles is always an array
-                    for comp in node.props[item].val:
-                        compatible2paths[comp].append(node.path)
+        for comp in node.compats:
+            compatible2paths[comp].append(node.path)
 
         if node.regs is not None:
             cmake_props.append(f'"DT_REG|{node.path}|NUM" "{len(node.regs)}"')