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[u-boot-marvell,RESEND,10/11] arm: mvebu: turris_mox: Fix unstable board topology reading

Message ID 20211126135715.26485-11-kabel@kernel.org
State Accepted
Commit 08370038df6c92a1bfe1aede55545a505e268305
Delegated to: Stefan Roese
Headers show
Series Some mvebu comphy + mox + fdt_support changes | expand

Commit Message

Marek Behún Nov. 26, 2021, 1:57 p.m. UTC 
From: Marek Behún <marek.behun@nic.cz>

The pre-relocation board topology reading in board_fix_fdt() is
unstable: sometimes wrong data are read from the SPI bus.

This is due to wrong order of SPI bus configuration instructions: we
first need to set the pins to SPI mode, and only after that configure
the bus.

Also add a 1ms delay before enabling chip-select, so that the clock pin
is high for some time before reading the bus.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
---
 board/CZ.NIC/turris_mox/turris_mox.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/board/CZ.NIC/turris_mox/turris_mox.c b/board/CZ.NIC/turris_mox/turris_mox.c
index 06616257d7..fab41c04b5 100644
--- a/board/CZ.NIC/turris_mox/turris_mox.c
+++ b/board/CZ.NIC/turris_mox/turris_mox.c
@@ -56,9 +56,11 @@  int board_fix_fdt(void *blob)
 	 * to read SPI by reading/writing SPI registers directly
 	 */
 
-	writel(0x10df, ARMADA_37XX_SPI_CFG);
 	/* put pin from GPIO to SPI mode */
 	clrbits_le32(ARMADA_37XX_NB_GPIO_SEL, BIT(12));
+	/* configure cpol, cpha, prescale */
+	writel(0x10df, ARMADA_37XX_SPI_CFG);
+	mdelay(1);
 	/* enable SPI CS1 */
 	setbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));