| Message ID | 1519727107-5821-1-git-send-email-eugen.hristev@microchip.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 9581329eff9db72ab4fbb46a594fd7fdda3c51b0 |
| Headers | show |
On 27/02/2018 at 11:25, Eugen Hristev wrote: > The datasheet recommends initializing FIFOs before > SPI enable. If we do not do it like this, there may be > a strange behavior. We noticed that DMA does not work properly > with FIFOs if we do not clear them beforehand or enable them > before SPIEN. > > Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> Ok, good: Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> > --- > drivers/spi/spi-atmel.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c > index 6694709..0478758 100644 > --- a/drivers/spi/spi-atmel.c > +++ b/drivers/spi/spi-atmel.c > @@ -1489,6 +1489,11 @@ static void atmel_spi_init(struct atmel_spi *as) > { > spi_writel(as, CR, SPI_BIT(SWRST)); > spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ > + > + /* It is recommended to enable FIFOs first thing after reset */ > + if (as->fifo_size) > + spi_writel(as, CR, SPI_BIT(FIFOEN)); > + > if (as->caps.has_wdrbt) { > spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS) > | SPI_BIT(MSTR)); > @@ -1499,9 +1504,6 @@ static void atmel_spi_init(struct atmel_spi *as) > if (as->use_pdc) > spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); > spi_writel(as, CR, SPI_BIT(SPIEN)); > - > - if (as->fifo_size) > - spi_writel(as, CR, SPI_BIT(FIFOEN)); > } > > static int atmel_spi_probe(struct platform_device *pdev) >
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 6694709..0478758 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -1489,6 +1489,11 @@ static void atmel_spi_init(struct atmel_spi *as) { spi_writel(as, CR, SPI_BIT(SWRST)); spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + + /* It is recommended to enable FIFOs first thing after reset */ + if (as->fifo_size) + spi_writel(as, CR, SPI_BIT(FIFOEN)); + if (as->caps.has_wdrbt) { spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS) | SPI_BIT(MSTR)); @@ -1499,9 +1504,6 @@ static void atmel_spi_init(struct atmel_spi *as) if (as->use_pdc) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); spi_writel(as, CR, SPI_BIT(SPIEN)); - - if (as->fifo_size) - spi_writel(as, CR, SPI_BIT(FIFOEN)); } static int atmel_spi_probe(struct platform_device *pdev)
The datasheet recommends initializing FIFOs before SPI enable. If we do not do it like this, there may be a strange behavior. We noticed that DMA does not work properly with FIFOs if we do not clear them beforehand or enable them before SPIEN. Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> --- drivers/spi/spi-atmel.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)