diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index e2051f3..97b60b3 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -258,6 +258,8 @@
 	/* other constraints relevant to this driver */
 	u16			flags;
 #define SPI_MASTER_HALF_DUPLEX	BIT(0)		/* can't do full duplex */
+#define SPI_MASTER_NO_RX	BIT(1)		/* can't do buffer read */
+#define SPI_MASTER_NO_TX	BIT(2)		/* can't do buffer write */
 
 	/* Setup mode and clock, etc (spi driver may call many times).
 	 *
@@ -538,42 +540,7 @@
 }
 
 extern int spi_setup(struct spi_device *spi);
-
-/**
- * spi_async - asynchronous SPI transfer
- * @spi: device with which data will be exchanged
- * @message: describes the data transfers, including completion callback
- * Context: any (irqs may be blocked, etc)
- *
- * This call may be used in_irq and other contexts which can't sleep,
- * as well as from task contexts which can sleep.
- *
- * The completion callback is invoked in a context which can't sleep.
- * Before that invocation, the value of message->status is undefined.
- * When the callback is issued, message->status holds either zero (to
- * indicate complete success) or a negative error code.  After that
- * callback returns, the driver which issued the transfer request may
- * deallocate the associated memory; it's no longer in use by any SPI
- * core or controller driver code.
- *
- * Note that although all messages to a spi_device are handled in
- * FIFO order, messages may go to different devices in other orders.
- * Some device might be higher priority, or have various "hard" access
- * time requirements, for example.
- *
- * On detection of any fault during the transfer, processing of
- * the entire message is aborted, and the device is deselected.
- * Until returning from the associated message completion callback,
- * no other spi_message queued to that device will be processed.
- * (This rule applies equally to all the synchronous transfer calls,
- * which are wrappers around this core asynchronous primitive.)
- */
-static inline int
-spi_async(struct spi_device *spi, struct spi_message *message)
-{
-	message->spi = spi;
-	return spi->master->transfer(spi, message);
-}
+extern int spi_async(struct spi_device *spi, struct spi_message *message);
 
 /*---------------------------------------------------------------------------*/