Vim3 - Vcc5 BUG


I am developing a Sound card that uses I2C/I2S and 5V (PIns 1 and 2) from the gpio header.
The I2C issues have been resolved, but now I can see an issue with 5V from pins 1 and 2.

The problem is that my device is left in a weird state after boot because the 5v rail dropped to 0v for 50ms. Which is not enough for a complete reset of the PCB.

I tried to trace what part of the kernel is setting GPIOH_8 low (device tree node regulator-vcc_5v),
but I could not find a set gpio 0 for that pin.
If I change the device node regulator-vcc_5v from GPIOH_8 to GPIOH_6, the issue doesn’t happen, but also I cant see the same low period on GPIOH_6.

Does anybody know why at the end of the boot, around 8 seconds after the kernel started, the VCC 5v is reset?
And how can VCC 5v be zero if GPIOH_8 is never set to zero?

Picture: Vim3_VCC5V_BUG - Image on Pasteboard


Have you used a DSO to monitor the power supply line voltage to rule out any anomalies on input voltage?

What OS and kernel are you running?