diff mbox series

[u-boot-marvell,1/4] arm: mvebu: turris_mox: Fix early SPI communication

Message ID 20200330171926.26119-1-marek.behun@nic.cz
State Superseded
Delegated to: Stefan Roese
Headers show
Series [u-boot-marvell,1/4] arm: mvebu: turris_mox: Fix early SPI communication | expand

Commit Message

Marek Behun March 30, 2020, 5:19 p.m. UTC
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>
---
 board/CZ.NIC/turris_mox/turris_mox.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Stefan Roese March 31, 2020, 10:14 a.m. UTC | #1
Hi Marek,

On 30.03.20 19:19, Marek Behún wrote:
> 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>
> ---
>   board/CZ.NIC/turris_mox/turris_mox.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/board/CZ.NIC/turris_mox/turris_mox.c b/board/CZ.NIC/turris_mox/turris_mox.c
> index 377191baef..7118096f32 100644
> --- a/board/CZ.NIC/turris_mox/turris_mox.c
> +++ b/board/CZ.NIC/turris_mox/turris_mox.c
> @@ -67,9 +67,9 @@ 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);
> +	clrbits_le32(ARMADA_37XX_NB_GPIO_SEL, BIT(12));
> +	setbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));
>   
>   	while (!(readl(ARMADA_37XX_SPI_CTRL) & 0x2))
>   		udelay(1);
> @@ -89,7 +89,7 @@ int board_fix_fdt(void *blob)
>   
>   	size = i;
>   
> -	writel(0x5b, ARMADA_37XX_SPI_CTRL);
> +	clrbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));

Could you please add some comments to those bit manipulations above? I
know it was not there before. But please add something like the commit
text here, explaining what this code is doing and why.

Thanks,
Stefan
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 377191baef..7118096f32 100644
--- a/board/CZ.NIC/turris_mox/turris_mox.c
+++ b/board/CZ.NIC/turris_mox/turris_mox.c
@@ -67,9 +67,9 @@  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);
+	clrbits_le32(ARMADA_37XX_NB_GPIO_SEL, BIT(12));
+	setbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));
 
 	while (!(readl(ARMADA_37XX_SPI_CTRL) & 0x2))
 		udelay(1);
@@ -89,7 +89,7 @@  int board_fix_fdt(void *blob)
 
 	size = i;
 
-	writel(0x5b, ARMADA_37XX_SPI_CTRL);
+	clrbits_le32(ARMADA_37XX_SPI_CTRL, BIT(17));
 
 	if (size > 1 && (topology[1] == MOX_MODULE_PCI ||
 			 topology[1] == MOX_MODULE_USB3 ||