[PATCH 3/4] spi: a3700: Allow to enable or disable FIFO mode

[Maxime Chevallier]

The armada 3700 SPI controller allows to make transfers without using
the 32 bytes RFIFO and WFIFO.

This commit enable switching between FIFO and non-FIFO mode, which is
necessary to implement full-duplex transfers.

Signed-off-by: Maxime Chevallier <maxime.chevallier at smile.fr>
---
 drivers/spi/spi-armada-3700.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c
index 8048468..b387309 100644
--- a/drivers/spi/spi-armada-3700.c
+++ b/drivers/spi/spi-armada-3700.c
@@ -186,12 +186,15 @@ static int a3700_spi_pin_mode_set(struct a3700_spi *a3700_spi,
 	return 0;
 }
 
-static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi)
+static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi, bool enable)
 {
 	u32 val;
 
 	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
-	val |= A3700_SPI_FIFO_MODE;
+	if (enable)
+		val |= A3700_SPI_FIFO_MODE;
+	else
+		val &= ~A3700_SPI_FIFO_MODE;
 	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
 }
 
@@ -299,7 +302,7 @@ static int a3700_spi_init(struct a3700_spi *a3700_spi)
 		a3700_spi_deactivate_cs(a3700_spi, i);
 
 	/* Enable FIFO mode */
-	a3700_spi_fifo_mode_set(a3700_spi);
+	a3700_spi_fifo_mode_set(a3700_spi, true);
 
 	/* Set SPI mode */
 	a3700_spi_mode_set(a3700_spi, master->mode_bits);
-- 
2.1.4