diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
index 56ea053f72f2..83844f8b862a 100644
--- a/tools/spi/spidev_test.c
+++ b/tools/spi/spidev_test.c
@@ -47,7 +47,7 @@ static int transfer_size;
 static int iterations;
 static int interval = 5; /* interval in seconds for showing transfer rate */
 
-uint8_t default_tx[] = {
+static uint8_t default_tx[] = {
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
 	0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
@@ -56,8 +56,8 @@ uint8_t default_tx[] = {
 	0xF0, 0x0D,
 };
 
-uint8_t default_rx[ARRAY_SIZE(default_tx)] = {0, };
-char *input_tx;
+static uint8_t default_rx[ARRAY_SIZE(default_tx)] = {0, };
+static char *input_tx;
 
 static void hex_dump(const void *src, size_t length, size_t line_size,
 		     char *prefix)