dt: dt-extract-compatibles: Add flag for driver matching compatibles

Add a new flag, '--driver-match', to the dt-extract-compatibles script
that causes it to only print out compatibles that are expected to match
a driver. This output can then be used by tests to detect device probe
failures.

In order to filter the compatibles down to only ones that will match to
a driver, the following is considered:
- A compatible needs to show up in a driver's of_match_table for it to
  be matched to a driver
- Compatibles that are used in both of_match_table and OF_DECLARE type
  macros can't be expected to match to a driver and so are ignored.
  One exception is CLK_OF_DECLARE_DRIVER, since it indicates that a
  driver will also later probe, so compatibles in this macro are not
  ignored.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20230828211424.2964562-3-nfraprado@collabora.com
Signed-off-by: Rob Herring <robh@kernel.org>

scripts/dtc/dt-extract-compatibles

@@ -7,11 +7,15 @@ import re
 import argparse
 
 
-def parse_of_declare_macros(data):
+def parse_of_declare_macros(data, include_driver_macros=True):
 	""" Find all compatible strings in OF_DECLARE() style macros """
 	compat_list = []
 	# CPU_METHOD_OF_DECLARE does not have a compatible string
-	for m in re.finditer(r'(?<!CPU_METHOD_)(IRQCHIP|OF)_(DECLARE|MATCH)(_DRIVER)?\(.*?\)', data):
+	if include_driver_macros:
+		re_macros = r'(?<!CPU_METHOD_)(IRQCHIP|OF)_(DECLARE|MATCH)(_DRIVER)?\(.*?\)'
+	else:
+		re_macros = r'(?<!CPU_METHOD_)(IRQCHIP|OF)_(DECLARE|MATCH)\(.*?\)'
+	for m in re.finditer(re_macros, data):
 		try:
 			compat = re.search(r'"(.*?)"', m[0])[1]
 		except:
@@ -22,24 +26,52 @@ def parse_of_declare_macros(data):
 	return compat_list
 
 
-def parse_of_device_id(data):
+def parse_of_device_id(data, match_table_list=None):
 	""" Find all compatible strings in of_device_id structs """
 	compat_list = []
-	for m in re.finditer(r'of_device_id(\s+\S+)?\s+\S+\[\](\s+\S+)?\s*=\s*({.*?);', data):
-		compat_list += re.findall(r'\.compatible\s+=\s+"(\S+)"', m[3])
+	for m in re.finditer(r'of_device_id(\s+\S+)?\s+(\S+)\[\](\s+\S+)?\s*=\s*({.*?);', data):
+		if match_table_list is not None and m[2] not in match_table_list:
+			continue
+		compat_list += re.findall(r'\.compatible\s+=\s+"(\S+)"', m[4])
 
 	return compat_list
 
 
-def parse_compatibles(file):
+def parse_of_match_table(data):
+	""" Find all driver's of_match_table """
+	match_table_list = []
+	for m in re.finditer(r'\.of_match_table\s+=\s+(of_match_ptr\()?([a-zA-Z0-9_-]+)', data):
+		match_table_list.append(m[2])
+
+	return match_table_list
+
+
+def parse_compatibles(file, compat_ignore_list):
 	with open(file, 'r', encoding='utf-8') as f:
 		data = f.read().replace('\n', '')
 
-	compat_list = parse_of_declare_macros(data)
-	compat_list += parse_of_device_id(data)
+	if compat_ignore_list is not None:
+		# For a compatible in the DT to be matched to a driver it needs to show
+		# up in a driver's of_match_table
+		match_table_list = parse_of_match_table(data)
+		compat_list = parse_of_device_id(data, match_table_list)
+
+		compat_list = [compat for compat in compat_list if compat not in compat_ignore_list]
+	else:
+		compat_list = parse_of_declare_macros(data)
+		compat_list += parse_of_device_id(data)
 
 	return compat_list
 
+def parse_compatibles_to_ignore(file):
+	with open(file, 'r', encoding='utf-8') as f:
+		data = f.read().replace('\n', '')
+
+	# Compatibles that show up in OF_DECLARE macros can't be expected to
+	# match a driver, except for the _DRIVER ones.
+	return parse_of_declare_macros(data, include_driver_macros=False)
+
+
 def print_compat(filename, compatibles):
 	if not compatibles:
 		return
@@ -63,10 +95,17 @@ if __name__ == "__main__":
 	ap = argparse.ArgumentParser()
 	ap.add_argument("cfile", type=str, nargs='*', help="C source files or directories to parse")
 	ap.add_argument('-H', '--with-filename', help="Print filename with compatibles", action="store_true")
+	ap.add_argument('-d', '--driver-match', help="Only print compatibles that should match to a driver", action="store_true")
 	args = ap.parse_args()
 
 	show_filename = args.with_filename
+	compat_ignore_list = None
+
+	if args.driver_match:
+		compat_ignore_list = []
+		for f in files_to_parse(args.cfile):
+			compat_ignore_list.extend(parse_compatibles_to_ignore(f))
 
 	for f in files_to_parse(args.cfile):
-		compat_list = parse_compatibles(f)
+		compat_list = parse_compatibles(f, compat_ignore_list)
 		print_compat(f, compat_list)