arm: mvebu: turris_mox: Fix early SPI communication

The SPI clock signal changes value when the SPI configuration register
is configured. This can sometimes lead to the device misinterpreting
the enablement of the SPI controller as actual clock tick.
This can be solved by first setting the SPI CS1 pin from GPIO to SPI mode,
and only after that writing the SPI configuration register.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Marek Behún 2020-04-08 12:02:03 +02:00 committed by Stefan Roese
parent 27f48f7dc4
commit b80ca8176d

View file

@ -67,9 +67,11 @@ int board_fix_fdt(void *blob)
* to read SPI by reading/writing SPI registers directly
*/
writel(0x563fa, ARMADA_37XX_NB_GPIO_SEL);
writel(0x10df, ARMADA_37XX_SPI_CFG);
writel(0x2005b, ARMADA_37XX_SPI_CTRL);
/* put pin from GPIO to SPI mode */
clrbits_le32(ARMADA_37XX_NB_GPIO_SEL, BIT(12));
/* enable SPI CS1 */
setbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));
while (!(readl(ARMADA_37XX_SPI_CTRL) & 0x2))
udelay(1);
@ -89,7 +91,8 @@ int board_fix_fdt(void *blob)
size = i;
writel(0x5b, ARMADA_37XX_SPI_CTRL);
/* disable SPI CS1 */
clrbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));
if (size > 1 && (topology[1] == MOX_MODULE_PCI ||
topology[1] == MOX_MODULE_USB3 ||