diff --git a/ni845x_spi.c b/ni845x_spi.c
index c1dd59c..a475598 100644
--- a/ni845x_spi.c
+++ b/ni845x_spi.c
@@ -390,7 +390,7 @@
 		ni845x_report_error("ni845xCloseFindDeviceHandle", tmp);
 }
 
-int ni845x_spi_init(struct flashprog_programmer *const prog)
+static int ni845x_spi_init(struct flashprog_programmer *const prog)
 {
 	char *speed_str = NULL;
 	char *CS_str = NULL;