On 2016-11-17 04:16, Sanchayan Maity wrote:
> 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;
> + }
How about:
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_CONT;
Avoids code duplication...
--
Stefan
> dspi->tx += tx_word + 1;
>
> dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
