diff --git a/arch/arm/src/stm32/stm32_spi.h b/arch/arm/src/stm32/stm32_spi.h
index e40db48ddd..62f304dfb7 100644
--- a/arch/arm/src/stm32/stm32_spi.h
+++ b/arch/arm/src/stm32/stm32_spi.h
@@ -54,7 +54,8 @@
 #undef EXTERN
 #if defined(__cplusplus)
 #define EXTERN extern "C"
-extern "C" {
+extern "C"
+{
 #else
 #define EXTERN extern
 #endif
@@ -99,29 +100,41 @@ enum    spi_dev_e;
  *
  ************************************************************************************/
 
-EXTERN void  stm32_spi1select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi1status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi1cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI1
+void stm32_spi1select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi1status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi1cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
-EXTERN void  stm32_spi2select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi2status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi2cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI2
+void stm32_spi2select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi2status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi2cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
-EXTERN void  stm32_spi3select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi3status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi3cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI3
+void stm32_spi3select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi3status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi3cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
-EXTERN void  stm32_spi4select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi4status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi4cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI4
+void stm32_spi4select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi4status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi4cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
-EXTERN void  stm32_spi5select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi5status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi5cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI5
+void stm32_spi5select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi5status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi5cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
-EXTERN void  stm32_spi6select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
-EXTERN uint8_t stm32_spi6status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
-EXTERN int stm32_spi6cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#ifdef CONFIG_STM32_SPI6
+void stm32_spi6select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+uint8_t stm32_spi6status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);
+int stm32_spi6cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool cmd);
+#endif
 
 #undef EXTERN
 #if defined(__cplusplus)