| Message ID | c1e51fc92dbcc9c31dcdcdfab3eed40d7745308a.1479384571.git.maitysanchayan@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <maitysanchayan@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, -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 <maitysanchayan@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, -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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,
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 <maitysanchayan@gmail.com> --- drivers/spi/spi-fsl-dspi.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)