[PATCH v4 2/2] checkpatch: Add option to not force /* */ for SPDX

[Petr Vorel]

Add option --spdx-cxx-comments to not force C comments (/* */) for SPDX.

As documented in aa19a176df95d6, this is required for some old
toolchains still have older assembler tools which cannot handle C++
style comments. This allows avoid forcing this for for projects which
vendored checkpatch.pl (e.g. LTP or u-boot).

Signed-off-by: Petr Vorel <pvorel@xxxxxxx>
---
Changes in v4 (all by Simon):
* Rename option to more specific (--ignore-old-toolchain =>
  --spdx-cxx-comments)
* Fix the help text (C++ => C comments)

Link to v3:
https://lore.kernel.org/lkml/20260408120603.54351-2-pvorel@xxxxxxx/

 scripts/checkpatch.pl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 38c448a8b7629..e5c320e0f230f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -61,6 +61,7 @@ my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
 my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
 my $max_line_length = 100;
 my $ignore_perl_version = 0;
+my $spdx_cxx_comments = 0;
 my $minimum_perl_version = 5.10.0;
 my $min_conf_desc_length = 4;
 my $spelling_file = "$D/spelling.txt";
@@ -137,6 +138,9 @@ Options:
                              file.  It's your fault if there's no backup or git
   --ignore-perl-version      override checking of perl version.  expect
                              runtime errors.
+  --spdx-cxx-comments        don't force C comments (/* */) for SPDX license
+                             (required by old toolchains). NOTE: it should *not*
+                             be used for Linux mainline.
   --codespell                Use the codespell dictionary for spelling/typos
                              (default:$codespellfile)
   --codespellfile            Use this codespell dictionary
@@ -346,6 +350,7 @@ GetOptions(
 	'fix!'		=> \$fix,
 	'fix-inplace!'	=> \$fix_inplace,
 	'ignore-perl-version!' => \$ignore_perl_version,
+	'spdx-cxx-comments!' => \$spdx_cxx_comments,
 	'debug=s'	=> \%debug,
 	'test-only=s'	=> \$tst_only,
 	'codespell!'	=> \$codespell,
@@ -3815,7 +3820,7 @@ sub process {
 			} elsif ($rawline =~ /^\+/) {
 				my $comment = "";
 				if ($realfile =~ /\.(h|s|S)$/) {
-					$comment = '/*';
+					$comment = $spdx_cxx_comments ? '//' : '/*';
 				} elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
 					$comment = '//';
 				} elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
-- 
2.53.0