[PATCH V2 09/20] spi: tegra114: add 3 wire transfer mode support

[Sowjanya Komatineni]

This patch adds 3 wire transfer support to SPI mode list along with
its implementation.

3 wire or Bi-directional mode uses only one serial data pin for the
transfer. SPI in master mode uses MOSI data line only and MISO data
line is not used.

Signed-off-by: Sowjanya Komatineni <skomatin...@nvidia.com>
---
 drivers/spi/spi-tegra114.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 239fb0c8c31f..212bb90aa0cb 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -755,6 +755,11 @@ static u32 tegra_spi_setup_transfer_one(struct spi_device 
*spi,
                else
                        command1 &= ~SPI_LSBIT_FE;
 
+               if (spi->mode & SPI_3WIRE)
+                       command1 |= SPI_BIDIROE;
+               else
+                       command1 &= ~SPI_BIDIROE;
+
                if (tspi->cs_control) {
                        if (tspi->cs_control != spi)
                                tegra_spi_writel(tspi, command1, SPI_COMMAND1);
@@ -1159,7 +1164,7 @@ static int tegra_spi_probe(struct platform_device *pdev)
 
        /* the spi->mode bits understood by this driver: */
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST |
-                           SPI_TX_DUAL | SPI_RX_DUAL;
+                           SPI_TX_DUAL | SPI_RX_DUAL | SPI_3WIRE;
        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
        master->setup = tegra_spi_setup;
        master->transfer_one_message = tegra_spi_transfer_one_message;
-- 
2.7.4