From c1788c4e433eda5b55c0182016c5ea9ddda4e9dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beat=20K=C3=BCng?= <beat-kueng@gmx.net>
Date: Thu, 27 Apr 2017 17:20:10 +0200
Subject: [PATCH] top: add module description & usage

---
 src/systemcmds/top/top.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/systemcmds/top/top.c b/src/systemcmds/top/top.c
index 6de022e9a0..99a402f490 100644
--- a/src/systemcmds/top/top.c
+++ b/src/systemcmds/top/top.c
@@ -50,12 +50,22 @@
 #include <systemlib/cpuload.h>
 #include <systemlib/printload.h>
 #include <drivers/drv_hrt.h>
+#include <px4_module.h>
 
 /**
  * Start the top application.
  */
 __EXPORT int top_main(int argc, char *argv[]);
 
+
+static void print_usage(void)
+{
+	PRINT_MODULE_DESCRIPTION("Monitor running processes and their CPU, stack usage, priority and state");
+
+	PRINT_MODULE_USAGE_NAME_SIMPLE("top", "system");
+	PRINT_MODULE_USAGE_COMMAND_DESCR("once", "print load only once");
+}
+
 int
 top_main(int argc, char *argv[])
 {
@@ -67,10 +77,16 @@ top_main(int argc, char *argv[])
 	/* clear screen */
 	dprintf(1, "\033[2J\n");
 
-	if (argc > 1 && !strcmp(argv[1], "once")) {
-		print_load(curr_time, 1, &load);
-		sleep(1);
-		print_load(hrt_absolute_time(), 1, &load);
+	if (argc > 1) {
+		if (!strcmp(argv[1], "once")) {
+			print_load(curr_time, 1, &load);
+			sleep(1);
+			print_load(hrt_absolute_time(), 1, &load);
+
+		} else {
+			print_usage();
+		}
+
 		return 0;
 	}