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spi: atmel: init FIFOs before spi enable 

commit 9581329eff 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>
pull/10/head
Eugen Hristev 2018-02-27 12:25:07 +02:00 committed by Greg Kroah-Hartman
parent 38866e8661
commit faddb17685
1 changed files with 5 additions and 3 deletions
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8
drivers/spi/spi-atmel.c
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@ -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)