diff --git a/tools/Makefile b/tools/Makefile
index 87e04ff..9aa699d 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -7,7 +7,7 @@
 CC	= gcc
 CFLAGS	= -Wall -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
 	  -Wcast-align -Wwrite-strings -Wnested-externs -Winline -W \
-	  -I../include
+	  -Wundef -Wmissing-prototypes -I../include
 
 CFLAGS	+= -O2
 # When debugging, use the following instead
diff --git a/tools/i2cdetect.c b/tools/i2cdetect.c
index d1843a9..fe8e6d9 100644
--- a/tools/i2cdetect.c
+++ b/tools/i2cdetect.c
@@ -33,7 +33,7 @@
 #define MODE_READ	2
 #define MODE_FUNC	3
 
-void help(void)
+static void help(void)
 {
 	fprintf(stderr,
 	        "Syntax: i2cdetect [-y] [-a] [-q|-r] I2CBUS [FIRST LAST]\n"
@@ -51,7 +51,7 @@ void help(void)
 	print_i2c_busses(0);
 }
 
-int scan_i2c_bus(int file, const int mode, const int first, const int last)
+static int scan_i2c_bus(int file, int mode, int first, int last)
 {
 	int i, j;
 	int res;
@@ -155,7 +155,7 @@ static const struct func all_func[] = {
 	{ .value = 0, .name = "" }
 };
 
-void print_functionality(unsigned long funcs)
+static void print_functionality(unsigned long funcs)
 {
 	int i;
 	
diff --git a/tools/i2cdump.c b/tools/i2cdump.c
index 72691ac..18c4997 100644
--- a/tools/i2cdump.c
+++ b/tools/i2cdump.c
@@ -29,7 +29,7 @@
 #include <linux/i2c-dev.h>
 #include "../version.h"
 
-void help(void)
+static void help(void)
 {
 	fprintf(stderr, "Syntax: i2cdump [-f] [-y] I2CBUS ADDRESS [MODE] "
 	        "[BANK [BANKREG]]\n"
diff --git a/tools/i2cget.c b/tools/i2cget.c
index 18c4fa6..81e6d69 100644
--- a/tools/i2cget.c
+++ b/tools/i2cget.c
@@ -32,9 +32,9 @@
 #include <linux/i2c-dev.h>
 #include "../version.h"
 
-void help(void) __attribute__ ((noreturn));
+static void help(void) __attribute__ ((noreturn));
 
-void help(void)
+static void help(void)
 {
 	fprintf(stderr, "Syntax: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS "
 	        "[DATA-ADDRESS [MODE]]\n"
@@ -50,7 +50,7 @@ void help(void)
 	exit(1);
 }
 
-int check_funcs(int file, int i2cbus, int size, int daddress, int pec)
+static int check_funcs(int file, int i2cbus, int size, int daddress, int pec)
 {
 	unsigned long funcs;
 
@@ -102,7 +102,8 @@ int check_funcs(int file, int i2cbus, int size, int daddress, int pec)
 	return 0;
 }
 
-int confirm(const char *filename, int address, int size, int daddress, int pec)
+static int confirm(const char *filename, int address, int size, int daddress,
+		   int pec)
 {
 	int dont = 0;
 
diff --git a/tools/i2cset.c b/tools/i2cset.c
index abeabe8..f60899e 100644
--- a/tools/i2cset.c
+++ b/tools/i2cset.c
@@ -29,9 +29,9 @@
 #include <linux/i2c-dev.h>
 #include "../version.h"
 
-void help(void) __attribute__ ((noreturn));
+static void help(void) __attribute__ ((noreturn));
 
-void help(void)
+static void help(void)
 {
 	fprintf(stderr, "Syntax: i2cset [-f] [-y] I2CBUS CHIP-ADDRESS DATA-ADDRESS "
 	        "VALUE [MODE] [MASK]\n"