checkpatch: warn on CamelCase variable names

Store the camelcase variables in a hash and only emit a warning on the
first use of each new variable.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -1398,6 +1398,8 @@ sub process {
 	my %suppress_export;
 	my $suppress_statement = 0;
 
+	my %camelcase = ();
+
 	# Pre-scan the patch sanitizing the lines.
 	# Pre-scan the patch looking for any __setup documentation.
 	#
@@ -2905,12 +2907,17 @@ sub process {
 			}
 		}
 
-#studly caps, commented out until figure out how to distinguish between use of existing and adding new
-#		if (($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
-#		    print "No studly caps, use _\n";
-#		    print "$herecurr";
-#		    $clean = 0;
-#		}
+#CamelCase
+		while ($line =~ m{($Constant|$Lval)}g) {
+			my $var = $1;
+			if ($var !~ /$Constant/ &&
+			    $var =~ /[A-Z]\w*[a-z]|[a-z]\w*[A-Z]/ &&
+			    !defined $camelcase{$var}) {
+				$camelcase{$var} = 1;
+				WARN("CAMELCASE",
+				     "Avoid CamelCase: <$var>\n" . $herecurr);
+			}
+		}
 
 #no spaces allowed after \ in define
 		if ($line=~/\#\s*define.*\\\s$/) {