diff --git a/arch/arm/src/stm32f7/stm32_serial.c b/arch/arm/src/stm32f7/stm32_serial.c
index bcf9dd6b275..1e08b0366c3 100644
--- a/arch/arm/src/stm32f7/stm32_serial.c
+++ b/arch/arm/src/stm32f7/stm32_serial.c
@@ -321,7 +321,7 @@
 #  define UART8_TXBUFSIZE_ALGN TXDMA_BUF_ALIGN
 #endif
 
-#if SERIAL_HAVE_TXDMA
+#ifdef SERIAL_HAVE_TXDMA
 /* DMA priority */
 
 #  ifndef CONFIG_USART_TXDMAPRIO