UPSTREAM: checkpatch: ignore SI unit CamelCase variants like "_uV"

Many existing variable names use SI like variants that should be otherwise
obvious and acceptable.

Whitelist them from the CamelCase message.

Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Phil Carmody <phil.carmody@partner.samsung.com>
Acked-by: Phil Carmody <phil.carmody@partner.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 22735ce857a2d9f4e6eec37c36be3fcf9d21d154)
Cherry-picked from torvalds/linux.git/master.

BUG=None
TEST=None

Change-Id: I87a1b21514adf551913d41b22e84f6fc42a36c4c
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/231130
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
diff --git a/checkpatch.pl b/checkpatch.pl
index c2c9b21..c197ac5 100755
--- a/checkpatch.pl
+++ b/checkpatch.pl
@@ -2943,7 +2943,10 @@
 			my $var = $1;
 			if ($var !~ /$Constant/ &&
 			    $var =~ /[A-Z]\w*[a-z]|[a-z]\w*[A-Z]/ &&
+#Ignore Page<foo> variants
 			    $var !~ /"^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
+#Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
+			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/ &&
 			    !defined $camelcase{$var}) {
 				$camelcase{$var} = 1;
 				WARN("CAMELCASE",