checkpatch: don't emit warnings for ID-base USB & PCI DT compatibles

The USB and PCI device bindings define some compatible patterns based on
device IDs that use the comma to separate vendor and product IDs.

These prefix patterns include:

  - ^usb(if)?[0-9a-f]{1,4},
  - ^pci[0-9a-f]{2,4},
  - ^pciclass,

These are not real vendor prefixes.  Don't emit warnings for them. 
Instead just skip over the DT compatible check altogether, and leave the
real check to the DT validator.  This avoids false positive warnings about
undocumented DT vendor prefixes and compatibles.

Note that the script mostly only checks the first compatible string of
each node, as it processes the source file line-by-line, and the check
only matches on the line with 'compatible = "..."'.  Otherwise there would
be more warnings from arch/mips/boot/dts/loongson/ls7a-pch.dtsi since that
file also includes compatibles like "pciclass0c0310" and "pciclass0c03"
which are not accepted either.  "pci0014,7a24.0" is not valid either, but
this patch leaves the real check to the DT validator.

Link: https://lore.kernel.org/20260707074629.3132930-1-wenst@chromium.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2b7a42bbdd94..7a846a3ea127 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3781,6 +3781,12 @@ sub process {
 			my $vp_file = $dt_path . "vendor-prefixes.yaml";
 
 			foreach my $compat (@compats) {
+				# Skip ID-based PCI and USB compatible patterns.
+				# DT validation will check them properly.
+				next if $compat =~ /^pciclass,/;
+				next if $compat =~ /^pci[a-f0-9]{2,4},/;
+				next if $compat =~ /^usb(if)?[a-f0-9]{1,4},/;
+
 				my $compat2 = $compat;
 				$compat2 =~ s/\,[a-zA-Z0-9]*\-/\,<\.\*>\-/;
 				my $compat3 = $compat;