diff mbox

spi: atmel: init FIFOs before spi enable

Message ID 1519727107-5821-1-git-send-email-eugen.hristev@microchip.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eugen Hristev Feb. 27, 2018, 10:25 a.m. UTC 
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>
---
 drivers/spi/spi-atmel.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 6694709..0478758 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)