[PATCH] checkpatch.pl: Add SPDX license tag check

[Rob Herring]

Add a check warning if SPDX-License-Identifier tags are not used in
newly added files.

Cc: Andy Whitcroft <a...@canonical.com>
Cc: Joe Perches <j...@perches.com>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Rob Herring <r...@kernel.org>
---
I rewrote my previous version to check more than just dts files. It also 
now looks for a tag in added files rather than trying a fuzzy match on 
freeform license text.

 scripts/checkpatch.pl | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 8b80bac055e4..6665735123e5 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2185,6 +2185,8 @@ sub process {
        my $commit_log_has_diff = 0;
        my $reported_maintainer_file = 0;
        my $non_utf8_charset = 0;
+       my $added_file = 0;
+       my $missing_spdx_license = 0;
 
        my $last_blank_line = 0;
        my $last_coalesced_string_linenr = -1;
@@ -2368,6 +2370,16 @@ sub process {
                $here = "#$linenr: " if (!$file);
                $here = "#$realline: " if ($file);
 
+               # determine if this is a new file
+               if ($line =~ m@^\-\-\-\s/@) {
+                       if ($line =~ m@/dev/null@) {
+                               $added_file = 1;
+                               $missing_spdx_license++;
+                       } else {
+                               $added_file = 0;
+                       }
+               }
+
                my $found_file = 0;
                # extract the filename as it passes
                if ($line =~ /^diff --git.*?(\S+)$/) {
@@ -2865,6 +2877,14 @@ sub process {
                        }
                }
 
+# check for using SPDX tag instead of free form license text
+               if ($added_file &&
+                   ($rawline =~ /\bSPDX-License-Identifier/ ||
+                    $realfile =~ /Documentation/)) {
+                       $missing_spdx_license--;
+                       $added_file = 0;
+               }
+
 # check we are in a valid source file if not then ignore this hunk
                next if ($realfile !~ /\.(h|c|s|S|sh|dtsi|dts)$/);
 
@@ -6399,6 +6419,11 @@ sub process {
                      "Missing Signed-off-by: line(s)\n");
        }
 
+       if ($missing_spdx_license) {
+               WARN("SPDX_LICENSE_TAG",
+                    "Missing SPDX-License-Identifier tags in added files. Use 
tags instead of full license text.\n");
+       }
+
        print report_dump();
        if ($summary && !($clean == 1 && $quiet == 1)) {
                print "$filename " if ($summary_file);
-- 
2.14.1