[RFC/PATCH,2/2] driver: spi: Add quad spi read support

Commit Message

Poddar, Sourav July 31, 2013, 5:47 a.m. UTC

Since, qspi controller uses quad read.

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

This patch has been done on top of the following patch[1], which is just the
basic idea of adding dual/quad support in spi framework.
$subject patch will undergo changes once the ongoing discussion in the
community is freezed.

This patch is posted to demonstrate how patch 1 of the series will support
quad read.

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

Signed-off-by: Sourav Poddar <[e-mail]>
---
 drivers/spi/spi-ti-qspi.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 02b67e9..a8c9587 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -273,6 +273,7 @@  static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t)
 {
 	u8 *rxbuf;
 	int wlen, count, ret;
+	unsigned cmd = qspi->cmd;
 
 	count = t->len;
 	rxbuf = t->rx_buf;
@@ -282,8 +283,18 @@  static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t)
 		dev_dbg(qspi->dev, "rx cmd %08x dc %08x\n",
 			qspi->cmd | QSPI_RD_SNGL, qspi->dc);
 		ti_qspi_write(qspi, qspi->dc, QSPI_SPI_DC_REG);
-		ti_qspi_write(qspi, qspi->cmd | QSPI_RD_SNGL,
-			QSPI_SPI_CMD_REG);
+		switch (t->bitwidth) {
+		case SPI_BITWIDTH_QUAD:
+			cmd |= QSPI_RD_QUAD;
+			break;
+		case SPI_BITWIDTH_DUAL:
+			cmd |= QSPI_RD_DUAL;
+			break;
+		case SPI_BITWIDTH_SINGLE:
+		default:
+			cmd |= QSPI_RD_SNGL;
+		}
+		ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG);
 		ret = wait_for_completion_timeout(&qspi->transfer_complete,
 					QSPI_COMPLETION_TIMEOUT);
 		if (ret == 0) {