Hello Stefan,
On 16-11-17 17:07:24, Stefan Agner wrote:
> 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...
Agreed. It's much better. Should be !dspi->cs_change though.
Will include it in next iteration.
Thanks & Regards,
Sanchayan.
>
> --
> Stefan
>
>
>
> > dspi->tx += tx_word + 1;
> >
> > dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
