diff --git a/src/main/common/utils.h b/src/main/common/utils.h
index 076b4680f2..e11ac32e88 100644
--- a/src/main/common/utils.h
+++ b/src/main/common/utils.h
@@ -55,9 +55,11 @@
 #define PP_CALL(macro, ...) macro(__VA_ARGS__)
 
 #if !defined(UNUSED)
-#define UNUSED(x) (void)(x)
+#define UNUSED(x) (void)(x) // Variables and parameters that are not used
 #endif
 
+#define DISCARD(x) (void)(x) // To explicitly ignore result of x (usually an I/O register access).
+
 #define STATIC_ASSERT(condition, name) _Static_assert((condition), #name)
 
 
diff --git a/src/main/drivers/bus_spi_stdperiph.c b/src/main/drivers/bus_spi_stdperiph.c
index 08ed3e3a22..76f636b16a 100644
--- a/src/main/drivers/bus_spi_stdperiph.c
+++ b/src/main/drivers/bus_spi_stdperiph.c
@@ -113,7 +113,7 @@ uint8_t spiTransferByte(SPI_TypeDef *instance, uint8_t txByte)
 {
     uint16_t spiTimeout = 1000;
 
-    instance->DR;
+    DISCARD(instance->DR);
 
     while (SPI_I2S_GetFlagStatus(instance, SPI_I2S_FLAG_TXE) == RESET)
         if ((spiTimeout--) == 0)
@@ -154,7 +154,7 @@ bool spiTransfer(SPI_TypeDef *instance, const uint8_t *txData, uint8_t *rxData,
     uint16_t spiTimeout = 1000;
 
     uint8_t b;
-    instance->DR;
+    DISCARD(instance->DR);
     while (len--) {
         b = txData ? *(txData++) : 0xFF;
         while (SPI_I2S_GetFlagStatus(instance, SPI_I2S_FLAG_TXE) == RESET) {