diff --git a/cpu/cc2538/lpm.c b/cpu/cc2538/lpm.c
index 709665e5b..bbc035219 100644
--- a/cpu/cc2538/lpm.c
+++ b/cpu/cc2538/lpm.c
@@ -105,7 +105,7 @@ static uint8_t max_pm;
 #define LPM_PERIPH_PERMIT_PM1_FUNCS_MAX 2
 #endif
 
-lpm_periph_permit_pm1_func_t
+static lpm_periph_permit_pm1_func_t
 periph_permit_pm1_funcs[LPM_PERIPH_PERMIT_PM1_FUNCS_MAX];
 /*---------------------------------------------------------------------------*/
 static bool