spi: tegra114: add SPI_LSB_FIRST support

Tegra SPI controller supports lsb first mode. Default is MSB bit first
and on selection of SPI_LSB_FIRST through SPI mode transmission happens
with LSB bit first.

This patch adds SPI_LSB_FIRST flag to mode_bits and also configures it
on request.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 929358e..0c52aee 100644 (file)
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -696,6 +696,11 @@ static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
                else if (req_mode == SPI_MODE_3)
                        command1 |= SPI_CONTROL_MODE_3;
 
+               if (spi->mode & SPI_LSB_FIRST)
+                       command1 |= SPI_LSBIT_FE;
+               else
+                       command1 &= ~SPI_LSBIT_FE;
+
                if (tspi->cs_control) {
                        if (tspi->cs_control != spi)
                                tegra_spi_writel(tspi, command1, SPI_COMMAND1);
@@ -1047,7 +1052,7 @@ static int tegra_spi_probe(struct platform_device *pdev)
                master->max_speed_hz = 25000000; /* 25MHz */
 
        /* the spi->mode bits understood by this driver: */
-       master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+       master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
        master->setup = tegra_spi_setup;
        master->transfer_one_message = tegra_spi_transfer_one_message;
        master->num_chipselect = MAX_CHIP_SELECT;