diff --git a/include/sound/mpu401.h b/include/sound/mpu401.h
index d45218b44dfe..68b634b75068 100644
--- a/include/sound/mpu401.h
+++ b/include/sound/mpu401.h
@@ -102,6 +102,21 @@ struct snd_mpu401 {
 #define MPU401C(mpu) (mpu)->cport
 #define MPU401D(mpu) (mpu)->port
 
+/*
+ * control register bits
+ */
+/* read MPU401C() */
+#define MPU401_RX_EMPTY		0x80
+#define MPU401_TX_FULL		0x40
+
+/* write MPU401C() */
+#define MPU401_RESET		0xff
+#define MPU401_ENTER_UART	0x3f
+
+/* read MPU401D() */
+#define MPU401_ACK		0xfe
+
+
 /*
 
  */
diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c
index dd6ec4266732..18cca2457d44 100644
--- a/sound/drivers/mpu401/mpu401_uart.c
+++ b/sound/drivers/mpu401/mpu401_uart.c
@@ -49,12 +49,10 @@ static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu);
 
  */
 
-#define snd_mpu401_input_avail(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x80))
-#define snd_mpu401_output_ready(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x40))
-
-#define MPU401_RESET		0xff
-#define MPU401_ENTER_UART	0x3f
-#define MPU401_ACK		0xfe
+#define snd_mpu401_input_avail(mpu) \
+	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY))
+#define snd_mpu401_output_ready(mpu) \
+	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL))
 
 /* Build in lowlevel io */
 static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data,