mx6ull: init_bandgap regression

[Fabio Estevam]

Hi Sven,

On Fri, Oct 24, 2025 at 6:23 AM Sven <u-boot at schwermer.no> wrote:
>
> Hi,
>
> We make an i.MX6ULL-based board that is built around the Phytec PCL063
> SoM. We have noticed a regression between v2022.01 (good) and v2022.04
> (bad). We have also found the following tags to be bad: v2022.07,
> v2023.01, v2024.01. We have bisected this and found the culprit to be
> c1af358c ("imx: mx6ull: fix REFTOP_VBGADJ setting"). This code still
> appears to be unchanged on upstream master.
>
> These are the symptoms: Very few of the thousands of devices that we
> manufacture (< 1%) fail to decompress a large XZ archive once in Linux
> userspace. We have not found any form of memory testing or other load
> that reproduces this issue. Reverting the offending patch fixes this
> behavior on the affected devices.

Please send a patch with the revert.

> Perhaps the NXP folks could chime in on the intended behavior. And the
> mismatch between commit message and comments mentioned in the offending
> patch.

Peng, can you look at it, please?

Thanks