mx6: peripheral clock from oscillator

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>
This commit is contained in:
Jorge Ramirez-Ortiz 2020-10-23 21:18:41 +02:00 committed by Stefano Babic
parent 33d1e52a5d
commit 74a039403c

View file

@ -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 */