4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eugen Hristev <[email protected]> commit 9581329eff9db72ab4fbb46a594fd7fdda3c51b0 upstream. 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 <[email protected]> Acked-by: Nicolas Ferre <[email protected]> Signed-off-by: Mark Brown <[email protected]> Cc: [email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/spi/spi-atmel.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -1489,6 +1489,11 @@ static void atmel_spi_init(struct atmel_ { 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_ 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)
