diff --git a/cpu/stm32/stmclk/stmclk_gx.c b/cpu/stm32/stmclk/stmclk_gx.c
index 72eed33fc2..ded9a44a0f 100644
--- a/cpu/stm32/stmclk/stmclk_gx.c
+++ b/cpu/stm32/stmclk/stmclk_gx.c
@@ -71,6 +71,10 @@
 #define RCC_CFGR_SW_HSE             (RCC_CFGR_SW_0)
 #define RCC_CFGR_SW_PLL             (RCC_CFGR_SW_1)
 
+#define RCC_CFGR_SWS_HSI            (0)
+#define RCC_CFGR_SWS_HSE            (RCC_CFGR_SWS_0)
+#define RCC_CFGR_SWS_PLL            (RCC_CFGR_SWS_1)
+
 #if CONFIG_CLOCK_HSISYS_DIV == 1
 #define CLOCK_HSI_DIV               (0)
 #elif CONFIG_CLOCK_HSISYS_DIV == 2