spi: make sure all transfer has bits_per_word set

When spi client does the spi transfer and does not sets
the bits_per_word for each transfer then set it as default
of spi device in spi core before calling low level transfer.

Removing the similar code from spi-tegra20-slink driver as
it is not required.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-tegra20-slink.c

@@ -727,8 +727,7 @@ static int tegra_slink_start_transfer_one(struct spi_device *spi,
 	unsigned long command;
 	unsigned long command2;
 
-	bits_per_word = t->bits_per_word ? t->bits_per_word :
-					spi->bits_per_word;
+	bits_per_word = t->bits_per_word;
 	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
 	if (!speed)
 		speed = tspi->spi_max_frequency;

drivers/spi/spi.c

@@ -1190,6 +1190,7 @@ EXPORT_SYMBOL_GPL(spi_setup);
 static int __spi_async(struct spi_device *spi, struct spi_message *message)
 {
 	struct spi_master *master = spi->master;
+	struct spi_transfer *xfer;
 
 	/* Half-duplex links include original MicroWire, and ones with
 	 * only one data pin like SPI_3WIRE (switches direction) or where
@@ -1198,7 +1199,6 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
 	 */
 	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
 			|| (spi->mode & SPI_3WIRE)) {
-		struct spi_transfer *xfer;
 		unsigned flags = master->flags;
 
 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
@@ -1211,6 +1211,15 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
 		}
 	}
 
+	/**
+	 * Set transfer bits_per_word as spi device default if it is not
+	 * set for this transfer.
+	 */
+	list_for_each_entry(xfer, &message->transfers, transfer_list) {
+		if (!xfer->bits_per_word)
+			xfer->bits_per_word = spi->bits_per_word;
+	}
+
 	message->spi = spi;
 	message->status = -EINPROGRESS;
 	return master->transfer(spi, message);