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| author | Eugen Hristev <eugen.hristev@microchip.com> | 2018-02-27 13:25:07 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-24 10:36:24 +0300 |
| commit | faddb17685f9f0507dcd28a3a4af3c63d5765407 (patch) | |
| tree | 49589f58a01e0c221ff177c2a85feff3ecd3dc97 /drivers/spi | |
| parent | 38866e866121454b5c6e2fc7eefe82fec97e810e (diff) | |
| download | linux-faddb17685f9f0507dcd28a3a4af3c63d5765407.tar.xz | |
spi: atmel: init FIFOs before spi enable
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 <eugen.hristev@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 669470971023..047875861df1 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) |