spi: atmel: init FIFOs before spi enable (9581329e) · Commits · 戴 / test

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

drivers/spi/spi-atmel.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -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)

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