checkpatch: check proper licensing of Devicetree bindings

According to Devicetree maintainers (see Link: below), the Devicetree
binding documents are preferrably licensed (GPL-2.0-only OR BSD-2-Clause).

Let's check that.  The actual check is a bit more relaxed, to allow more
liberal but compatible licensing (e.g.  GPL-2.0-or-later OR BSD-2-Clause).

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Cc: Jonas Karlman <jonas@kwiboo.se>,
Cc: Jernej Skrabec <jernej.skrabec@siol.net>,
Cc: Mark Rutland <mark.rutland@arm.com>,
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>,
Link: https://lore.kernel.org/lkml/20200108142132.GA4830@bogus/
Link: http://lkml.kernel.org/r/20200309215153.38824-1-lkundrak@v3.sk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 64cfd61..460a6b5 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3157,6 +3157,17 @@ sub process {
                                                WARN("SPDX_LICENSE_TAG",
                                                     "'$spdx_license' is not supported in LICENSES/...\n" . $herecurr);
                                        }
+                                       if ($realfile =~ m@^Documentation/devicetree/bindings/@ &&
+                                           not $spdx_license =~ /GPL-2\.0.*BSD-2-Clause/) {
+                                               my $msg_level = \&WARN;
+                                               $msg_level = \&CHK if ($file);
+                                               if (&{$msg_level}("SPDX_LICENSE_TAG",
+
+                                                                 "DT binding documents should be licensed (GPL-2.0-only OR BSD-2-Clause)\n" . $herecurr) &&
+                                                   $fix) {
+                                                       $fixed[$fixlinenr] =~ s/SPDX-License-Identifier: .*/SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)/;
+                                               }
+                                       }
                                }
                        }
                }