diff --git a/arch/arm/src/efm32/efm32_rmu.c b/arch/arm/src/efm32/efm32_rmu.c
index a03353c0b60..033cc522bde 100644
--- a/arch/arm/src/efm32/efm32_rmu.c
+++ b/arch/arm/src/efm32/efm32_rmu.c
@@ -66,10 +66,10 @@
 #ifdef CONFIG_EFM32_RMU_DEBUG
 typedef struct
 {
-    const uint32_t val;
-    const uint32_t mask;
-    const char*    str;
-}efm32_reset_cause_list_t;
+  const uint32_t val;
+  const uint32_t mask;
+  const char*    str;
+} efm32_reset_cause_list_t;
 #endif
 
 /************************************************************************************
diff --git a/arch/arm/src/efm32/efm32_rmu.h b/arch/arm/src/efm32/efm32_rmu.h
index f793b29fa9a..ce1def0c785 100644
--- a/arch/arm/src/efm32/efm32_rmu.h
+++ b/arch/arm/src/efm32/efm32_rmu.h
@@ -85,6 +85,7 @@ extern uint32_t g_efm32_rstcause;
  ************************************************************************************/
 
 void efm32_rmu_initialize(void);
+const char* efm32_reset_cause_list_str(uint32_t reg, unsigned int *idx);
 
 /************************************************************************************
  * Name: efm32_reset_cause_list_str