diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-omap2-mcspi.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 1d237e93a289..c47f95879833 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -459,6 +459,11 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, count = xfer->len; dma_count = xfer->len; + /* + * In the "End-of-Transfer Procedure" section for DMA RX in OMAP35x TRM + * it mentions reducing DMA transfer length by one element in master + * normal mode. + */ if (mcspi->fifo_depth == 0) dma_count -= es; @@ -478,6 +483,10 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, dmaengine_slave_config(mcspi_dma->dma_rx, &cfg); + /* + * Reduce DMA transfer length by one more if McSPI is + * configured in turbo mode. + */ if ((l & OMAP2_MCSPI_CHCONF_TURBO) && mcspi->fifo_depth == 0) dma_count -= es; @@ -507,6 +516,10 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, if (mcspi->fifo_depth > 0) return count; + /* + * Due to the DMA transfer length reduction the missing bytes must + * be read manually to receive all of the expected data. + */ omap2_mcspi_set_enable(spi, 0); elements = element_count - 1; |