[PATCH V5 1/4] spi: tegra114: add support for gpio based CS

[Sowjanya Komatineni]

This patch adds support for GPIO based CS control through SPI core
function spi_set_cs.

Signed-off-by: Sowjanya Komatineni <skomatin...@nvidia.com>
---
 drivers/spi/spi-tegra114.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index b1f31bb16659..f47417dd9edb 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -776,6 +776,10 @@ static u32 tegra_spi_setup_transfer_one(struct spi_device 
*spi,
                } else
                        tegra_spi_writel(tspi, command1, SPI_COMMAND1);
 
+               /* GPIO based chip select control */
+               if (spi->cs_gpiod)
+                       gpiod_set_value(spi->cs_gpiod, 1);
+
                command1 |= SPI_CS_SW_HW;
                if (spi->mode & SPI_CS_HIGH)
                        command1 |= SPI_CS_SW_VAL;
@@ -864,6 +868,10 @@ static int tegra_spi_setup(struct spi_device *spi)
        }
 
        spin_lock_irqsave(&tspi->lock, flags);
+       /* GPIO based chip select control */
+       if (spi->cs_gpiod)
+               gpiod_set_value(spi->cs_gpiod, 0);
+
        val = tspi->def_command1_reg;
        if (spi->mode & SPI_CS_HIGH)
                val &= ~SPI_CS_POL_INACTIVE(spi->chip_select);
@@ -893,6 +901,10 @@ static void tegra_spi_transfer_end(struct spi_device *spi)
        struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
        int cs_val = (spi->mode & SPI_CS_HIGH) ? 0 : 1;
 
+       /* GPIO based chip select control */
+       if (spi->cs_gpiod)
+               gpiod_set_value(spi->cs_gpiod, 0);
+
        if (cs_val)
                tspi->command1_reg |= SPI_CS_SW_VAL;
        else
@@ -1199,6 +1211,7 @@ static int tegra_spi_probe(struct platform_device *pdev)
                master->max_speed_hz = 25000000; /* 25MHz */
 
        /* the spi->mode bits understood by this driver: */
+       master->use_gpio_descriptors = true;
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST |
                            SPI_TX_DUAL | SPI_RX_DUAL | SPI_3WIRE;
        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
-- 
2.7.4