diff --git a/dts/arm/st/l4/stm32l4s5.dtsi b/dts/arm/st/l4/stm32l4s5.dtsi
new file mode 100644
index 00000000000..423e0edb160
--- /dev/null
+++ b/dts/arm/st/l4/stm32l4s5.dtsi
@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2020 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <st/l4/stm32l4r5.dtsi>
diff --git a/dts/arm/st/l4/stm32l4s5Xi.dtsi b/dts/arm/st/l4/stm32l4s5Xi.dtsi
new file mode 100644
index 00000000000..870b1d8c7ac
--- /dev/null
+++ b/dts/arm/st/l4/stm32l4s5Xi.dtsi
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2020 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <mem.h>
+#include <st/l4/stm32l4s5.dtsi>
+
+/ {
+	soc {
+		flash-controller@40022000 {
+			flash0: flash@8000000 {
+				reg = <0x08000000 DT_SIZE_K(2048)>;
+			};
+		};
+	};
+};