From: Eugen Hristev Date: Tue, 27 Feb 2018 10:25:07 +0000 (+0200) Subject: spi: atmel: init FIFOs before spi enable X-Git-Tag: v4.19~1334^2~2^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9581329eff9db72ab4fbb46a594fd7fdda3c51b0;p=platform%2Fkernel%2Flinux-rpi.git spi: atmel: init FIFOs before spi enable 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 Acked-by: Nicolas Ferre Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 4a11fc0..b7936f8 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -1512,6 +1512,11 @@ 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)); @@ -1522,9 +1527,6 @@ 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)