No subject

work this way on the i.MX28 either. The VDDIO Linreg is sourced from the
5V rail. So if we run from battery only we can not deactivate VDDIO from
DCDC by setting DISABLE_FET.

> The BootROM never hands over to U-Boot, so this really makes no sense. Can you 
> please explain ? The BootROM handles over to U-Boot SPL, which configures the 
> power block.
> 
Sorry I meant the U-Boot SPL.I not that familiar with U-Boot architecture.
> Also, I find it a very bad idea to depend on the BootROM to actually start the 
> DCDC converter. I don't think we can universally say the DCDC converter is 
> running when entering U-Boot SPL. I also don't think we can even depend on the 
> power block configuration when exiting the BootROM -- for example in JTAG Boot 
> Mode, the BootROM halts early in the boot process and will likely not configure 
> anything with regards to the power block.

I am with you at the point that proper initialization is very important
and we should not rely on BootROM.

If the system is running on battery only, we should not switch the VDDIO
regulator to Linreg mode because there are no 5V to source it. In
mxs_power_enable_4p2() all Regulators get switched to Linreg mode and
that kills the power to hole system and there by is triggering an
brownout reset.

The mxs_power_enable_4p2() function can only work if we assume
there is 5V present.

I hope I got clearer way this will not work in a battery only scenario.

Best regards,
Peter Schumann