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

[Patrick Pannuto <ppannuto@codeaurora.org>]

In (almost) every case, usleep_range is better than
usleep, as the precise (ish) wakeup - more accurately
the extra interrupt - from usleep is unnecessary.

usleep_range gives a much better chance of coalescing
processor wakeups.

Signed-off-by: Patrick Pannuto <ppannuto@codeaurora.org>
---
 scripts/checkpatch.pl |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e3625ac..0650ab9 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2578,6 +2578,11 @@ sub process {
 			}
 		}
 
+# prefer usleep_range over usleep
+		if ($line =~ /\busleep\s*\(.+\);/) {
+			WARN("usleep_range is preferred over usleep; 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