[RFC/PATCH 3/3] driver: spi: Add quad spi read support

[Sourav Poddar <sourav.poddar@ti.com>]

Since, qspi controller uses quad read.

Configuring the command register, if the transfer of data needs
quad lines.

This patch has been done on top of the following patch[1], which is still
under review/comments.
This patch will also go changes, as the parent patch[1] does.

[1]: http://comments.gmane.org/gmane.linux.kernel.spi.devel/14047

Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
---
 drivers/spi/spi-ti-qspi.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 430de9c..307cbed 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -258,8 +258,12 @@ static int qspi_read_msg(struct dra7xxx_qspi *qspi, struct spi_transfer *t)
 			qspi->cmd | QSPI_RD_SNGL, qspi->dc);
 		dra7xxx_writel(qspi, QSPI_WC_INT_EN, QSPI_INTR_ENABLE_SET_REG);
 		dra7xxx_writel(qspi, qspi->dc, QSPI_SPI_DC_REG);
-		dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_SNGL,
-			QSPI_SPI_CMD_REG);
+		if (t->bitwidth == SPI_BITWIDTH_QUAD)
+			dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_QUAD,
+				QSPI_SPI_CMD_REG);
+		else
+			dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_SNGL,
+				QSPI_SPI_CMD_REG);
 		wait_for_completion(&qspi->word_complete);
 		*rxbuf++ = dra7xxx_readl_data(qspi, QSPI_SPI_DATA_REG, wlen);
 		dev_dbg(qspi->dev, "rx done, read %02x\n", *(rxbuf-1));
-- 
1.7.1