[PATCH 3/4] Checkpatch: prefer usleep over udelay

[Patrick Pannuto <ppannuto@codeaurora.org>]

When possible, sleeping is (usually) better than delaying;
however, don't bother callers of udelay < 10us, as those
cases are generally not worth the switch to usleep

Signed-off-by: Patrick Pannuto <ppannuto@codeaurora.org>
---
 scripts/checkpatch.pl |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index bd88f11..892ae62 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2570,6 +2570,14 @@ sub process {
 			}
 		}
 
+# prefer usleep over udelay
+		if (($line =~ /\budelay\s*\(\s*(\w+)\s*\)/ {
+			# ignore udelay's < 10, however
+			if (! (($1 =~ /(\d+)/) && ($1 < 10)) ) {
+				CHK("usleep is preferred over udelay; see Documentation/timers/delays.txt\n" . $line);
+			}
+		}
+
 # warn about #ifdefs in C files
 #		if ($line =~ /^.\s*\#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
 #			print "#ifdef in C files should be avoided\n";
-- 
1.7.2