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 --- board/CZ.NIC/turris_mox/turris_mox.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/board/CZ.NIC/turris_mox/turris_mox.c b/board/CZ.NIC/turris_mox/turris_mox.c index 502f6fc010..809ce82d20 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));