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>

diff --git a/arch/arm/mach-imx/mx6/soc.c b/arch/arm/mach-imx/mx6/soc.c
index a636107..f43a246 100644 (file)
--- 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 */