diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_mmio.c b/drivers/platform/x86/intel_speed_select_if/isst_if_mmio.c
index 2906cfee5d9c7832b8bddf7b8401e639996e2de9..ff49025ec0856ab587709a352442159bc97144c7 100644
--- a/drivers/platform/x86/intel_speed_select_if/isst_if_mmio.c
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_mmio.c
@@ -20,12 +20,12 @@ struct isst_mmio_range {
 	int end;
 };
 
-struct isst_mmio_range mmio_range_devid_0[] = {
+static struct isst_mmio_range mmio_range_devid_0[] = {
 	{0x04, 0x14},
 	{0x20, 0xD0},
 };
 
-struct isst_mmio_range mmio_range_devid_1[] = {
+static struct isst_mmio_range mmio_range_devid_1[] = {
 	{0x04, 0x14},
 	{0x20, 0x11C},
 };