edtlib: allow const arrays

Allow for having array types (array, uint8-array, string-array) be const.
This would allow for something like:

properties:
    reg-names:
        const: ["foo", "bar"]

To be supported.

Renamed function _check_prop_type_and_default to _check_prop_by_type
as part of this change and Moved the check for 'const' types into
_check_prop_by_type as its similar to the prop_type check and it was
easier to implement in _check_prop_by_type as we already extract
prop_type from the option in that function.

Signed-off-by: Kumar Gala <galak@kernel.org>

doc/build/dts/bindings.rst

diff --git a/doc/build/dts/bindings.rst b/doc/build/dts/bindings.rst
index 3065410..e32468b 100644
--- a/doc/build/dts/bindings.rst
+++ b/doc/build/dts/bindings.rst
@@ -415,7 +415,7 @@
        - <item2>
        ...
        - <itemN>
-     const: <string | int>
+     const: <string | int | array | uint8-array | string-array>
 
 Required properties
 +++++++++++++++++++

scripts/dts/python-devicetree/src/devicetree/edtlib.py

diff --git a/scripts/dts/python-devicetree/src/devicetree/edtlib.py b/scripts/dts/python-devicetree/src/devicetree/edtlib.py
index 9e7dc1b..5857cf8 100644
--- a/scripts/dts/python-devicetree/src/devicetree/edtlib.py
+++ b/scripts/dts/python-devicetree/src/devicetree/edtlib.py
@@ -1081,7 +1081,7 @@
                 # YAML doesn't have a native format for byte arrays. We need to
                 # convert those from an array like [0x12, 0x34, ...]. The
                 # format has already been checked in
-                # _check_prop_type_and_default().
+                # _check_prop_by_type().
                 if prop_type == "uint8-array":
                     return bytes(default)
                 return default
@@ -1132,7 +1132,7 @@
             return self.edt._node2enode[prop.to_path()]
 
         # prop_type == "compound". Checking that the 'type:'
-        # value is valid is done in _check_prop_type_and_default().
+        # value is valid is done in _check_prop_by_type().
         #
         # 'compound' is a dummy type for properties that don't fit any of the
         # patterns above, so that we can require all entries in 'properties:'
@@ -1346,7 +1346,7 @@
                 specifier_space = "gpio"
             else:
                 # Strip -s. We've already checked that property names end in -s
-                # if there is no specifier space in _check_prop_type_and_default().
+                # if there is no specifier space in _check_prop_by_type().
                 specifier_space = prop.name[:-1]
 
         res = []
@@ -1978,8 +1978,7 @@
                          f"'properties: {prop_name}: ...' in {self.path}, "
                          f"expected one of {', '.join(ok_prop_keys)}")
 
-            _check_prop_type_and_default(
-                prop_name, options, self.path)
+            _check_prop_by_type(prop_name, options, self.path)
 
             for true_false_opt in ["required", "deprecated"]:
                 if true_false_opt in options:
@@ -2002,11 +2001,6 @@
                 _err(f"enum in {self.path} for property '{prop_name}' "
                      "is not a list")
 
-            if "const" in options and not isinstance(options["const"],
-                                                     (int, str)):
-                _err(f"const in {self.path} for property '{prop_name}' "
-                     "is not a scalar")
-
 
 def bindings_from_paths(yaml_paths, ignore_errors=False):
     """
@@ -2391,12 +2385,13 @@
     _binding_inc_error("unrecognised node type in !include statement")
 
 
-def _check_prop_type_and_default(prop_name, options, binding_path):
-    # Binding._check_properties() helper. Checks 'type:', 'default:' and
-    # 'specifier-space:' for the property named 'prop_name'
+def _check_prop_by_type(prop_name, options, binding_path):
+    # Binding._check_properties() helper. Checks 'type:', 'default:',
+    # 'const:' and # 'specifier-space:' for the property named 'prop_name'
 
     prop_type = options.get("type")
     default = options.get("default")
+    const = options.get("const")
 
     if prop_type is None:
         _err(f"missing 'type:' for '{prop_name}' in 'properties' in "
@@ -2420,6 +2415,13 @@
             _err(f"'{prop_name}' in 'properties:' in {binding_path} "
                  f"has type 'phandle-array' and its name does not end in 's', "
                  f"but no 'specifier-space' was provided.")
+
+    const_types = {"int", "array", "uint8-array", "string", "string-array"}
+    if const and prop_type not in const_types:
+        _err(f"const in {binding_path} for property '{prop_name}' "
+             f"has type '{prop_type}', expected one of " +
+             ", ".join(const_types))
+
     # Check default
 
     if default is None:

scripts/dts/python-devicetree/tests/test-bindings/props.yaml

diff --git a/scripts/dts/python-devicetree/tests/test-bindings/props.yaml b/scripts/dts/python-devicetree/tests/test-bindings/props.yaml
index 40b4cb9..8174a9d 100644
--- a/scripts/dts/python-devicetree/tests/test-bindings/props.yaml
+++ b/scripts/dts/python-devicetree/tests/test-bindings/props.yaml
@@ -27,6 +27,7 @@
 
     string-array:
         type: string-array
+        const: ['foo', 'bar', 'baz']
 
     phandle-ref:
         type: phandle