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-rw-r--r--drivers/spi/spi.c56
1 files changed, 30 insertions, 26 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 39d3875..50f7fc3 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1473,33 +1473,37 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
* 2. keep tx/rx_nbits is contained by mode in spi_device
* 3. if SPI_3WIRE, tx/rx_nbits should be in single
*/
- if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
- xfer->tx_nbits != SPI_NBITS_DUAL &&
- xfer->tx_nbits != SPI_NBITS_QUAD)
- return -EINVAL;
- if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
- !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
- return -EINVAL;
- if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
- !(spi->mode & SPI_TX_QUAD))
- return -EINVAL;
- if ((spi->mode & SPI_3WIRE) &&
- (xfer->tx_nbits != SPI_NBITS_SINGLE))
- return -EINVAL;
+ if (xfer->tx_buf) {
+ if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
+ xfer->tx_nbits != SPI_NBITS_DUAL &&
+ xfer->tx_nbits != SPI_NBITS_QUAD)
+ return -EINVAL;
+ if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
+ !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
+ return -EINVAL;
+ if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
+ !(spi->mode & SPI_TX_QUAD))
+ return -EINVAL;
+ if ((spi->mode & SPI_3WIRE) &&
+ (xfer->tx_nbits != SPI_NBITS_SINGLE))
+ return -EINVAL;
+ }
/* check transfer rx_nbits */
- if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
- xfer->rx_nbits != SPI_NBITS_DUAL &&
- xfer->rx_nbits != SPI_NBITS_QUAD)
- return -EINVAL;
- if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
- !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
- return -EINVAL;
- if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
- !(spi->mode & SPI_RX_QUAD))
- return -EINVAL;
- if ((spi->mode & SPI_3WIRE) &&
- (xfer->rx_nbits != SPI_NBITS_SINGLE))
- return -EINVAL;
+ if (xfer->rx_buf) {
+ if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
+ xfer->rx_nbits != SPI_NBITS_DUAL &&
+ xfer->rx_nbits != SPI_NBITS_QUAD)
+ return -EINVAL;
+ if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
+ !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
+ return -EINVAL;
+ if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
+ !(spi->mode & SPI_RX_QUAD))
+ return -EINVAL;
+ if ((spi->mode & SPI_3WIRE) &&
+ (xfer->rx_nbits != SPI_NBITS_SINGLE))
+ return -EINVAL;
+ }
}
message->spi = spi;