Re: [PATCH] arm64: dts: ti: k3-am62a7-sk: Disable mmc Schmitt Trigger

[Judith Mendez <jm@ti.com>]

On 1/6/26 10:22 AM, Markus Schneider-Pargmann (TI.com) wrote:
> Remove Schmitt Trigger from mmc pins. With Schmitt Trigger enabled
> u-boot SPL is not able to read u-boot from mmc:
> 
>      Trying to boot from MMC2
>      Error reading cluster
>      spl_load_image_fat: error reading image u-boot.img, err - -22
>      Error: -22
>      SPL: Unsupported Boot Device!
>      SPL: failed to boot from all boot devices
>      ### ERROR ### Please RESET the board ###
> 
> I bisected this issue between u-boot v2025.10 and v2026.01 and found the
> devicetree merge to be the problem. At a closer look I found the
> k3-pinctrl.h changes. Disabling the Schmitt Trigger fixes the u-boot SPL
> failure to read from mmc.

I have tested 4 AM62A SK boards and I cannot replicate the issue
you are seeing. I do not see an issue with Schmitt Trigger in U-boot
nor Linux /:

Can you please run a quick tap sweep on MMC1 and MMC0 interfaces like
so? https://gist.github.com/jmenti/f4a73a8323e44bf717c6d2c528c499ca

This will give me an idea if whether we should be talking about
revisiting characterization with ST_ENA=1.

Also, are you able to replicate the issue on more than one board? Or is
this the only board you see the issue on?

~ Judith