[PATCHv2] mx6: peripheral clock from oscillator

[PATCHv2] mx6: peripheral clock from oscillator

[Jorge Ramirez-Ortiz]

In order to be able to run the I2C bus at 400Khz, the chip errata[1]
recommends that the peripheral clock runs out of the 24MHz oscillator.

Systems running I2C from OP-TEE before Linux executes - for example to
access a Secure Element [2] providing the cryptographic support - expect
this clock to be configured by the bootloader [3].

[1] IMX6SLCE Rev. 5, 02/2019, ERR007805.
[2] OP-TEE: support for NXP SE05X Plug and Trust (patch on the list).
[3] OP-TEE: check the imx_i2c.c driver (imx6 patch on the list).

Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
---
 arch/arm/mach-imx/mx6/soc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/mx6/soc.c b/arch/arm/mach-imx/mx6/soc.c
index e129286065..4c0a352574 100644
--- a/arch/arm/mach-imx/mx6/soc.c
+++ b/arch/arm/mach-imx/mx6/soc.c
@@ -26,6 +26,9 @@
 #include <imx_thermal.h>
 #include <mmc.h>
 
+#define has_err007805() \
+	(is_mx6sl() || is_mx6dl() || is_mx6solo() || is_mx6ull())
+
 struct scu_regs {
 	u32	ctrl;
 	u32	config;
@@ -469,7 +472,7 @@ int arch_cpu_init(void)
 	}
 
 	/* Set perclk to source from OSC 24MHz */
-	if (is_mx6sl())
+	if (has_err007805())
 		setbits_le32(&ccm->cscmr1, MXC_CCM_CSCMR1_PER_CLK_SEL_MASK);
 
 	imx_wdog_disable_powerdown(); /* Disable PDE bit of WMCR register */
-- 
2.17.1

[PATCHv2] mx6: peripheral clock from oscillator

[Fabio Estevam]

On Fri, Oct 23, 2020 at 4:18 PM Jorge Ramirez-Ortiz <jorge@foundries.io> wrote:
>
> In order to be able to run the I2C bus at 400Khz, the chip errata[1]
> recommends that the peripheral clock runs out of the 24MHz oscillator.
>
> Systems running I2C from OP-TEE before Linux executes - for example to
> access a Secure Element [2] providing the cryptographic support - expect
> this clock to be configured by the bootloader [3].
>
> [1] IMX6SLCE Rev. 5, 02/2019, ERR007805.
> [2] OP-TEE: support for NXP SE05X Plug and Trust (patch on the list).
> [3] OP-TEE: check the imx_i2c.c driver (imx6 patch on the list).
>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>

Reviewed-by: Fabio Estevam <festevam@gmail.com>

[PATCHv2] mx6: peripheral clock from oscillator

[sbabic at denx.de]

> In order to be able to run the I2C bus at 400Khz, the chip errata[1]
> recommends that the peripheral clock runs out of the 24MHz oscillator.
> Systems running I2C from OP-TEE before Linux executes - for example to
> access a Secure Element [2] providing the cryptographic support - expect
> this clock to be configured by the bootloader [3].
> [1] IMX6SLCE Rev. 5, 02/2019, ERR007805.
> [2] OP-TEE: support for NXP SE05X Plug and Trust (patch on the list).
> [3] OP-TEE: check the imx_i2c.c driver (imx6 patch on the list).
> Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
> Reviewed-by: Fabio Estevam <festevam@gmail.com>
Applied to u-boot-imx, master, thanks !

Best regards,
Stefano Babic

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