[PATCH 3/4] spi: spi-fsl-dspi: Fix continuous selection format

[Sanchayan Maity]

Current DMA implementation was not handling the continuous selection
format viz. SPI chip select would be deasserted even between sequential
serial transfers. Use the cs_change variable and correctly set or
reset the CONT bit accordingly for case where peripherals require
the chip select to be asserted between sequential transfers.

Signed-off-by: Sanchayan Maity <maitysancha...@gmail.com>
---
 drivers/spi/spi-fsl-dspi.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index aee8c88..164e2e1 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -258,9 +258,16 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
        }
 
        val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
-       dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
-                                       SPI_PUSHR_PCS(dspi->cs) |
-                                       SPI_PUSHR_CTAS(0);
+       if (dspi->cs_change) {
+               dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
+                                               SPI_PUSHR_PCS(dspi->cs) |
+                                               SPI_PUSHR_CTAS(0);
+       } else {
+               dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
+                                               SPI_PUSHR_PCS(dspi->cs) |
+                                               SPI_PUSHR_CTAS(0) |
+                                               SPI_PUSHR_CONT;
+       }
        dspi->tx += tx_word + 1;
 
        dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
-- 
2.10.2