Re: [PATCH] arm64: dts: ti: k3-am62a7-sk: Disable mmc Schmitt Trigger
From: Judith Mendez
Date: Wed Jan 14 2026 - 17:04:40 EST
Hi Markus,
On 1/14/26 3:16 AM, Markus Schneider-Pargmann wrote:
Hi Judith,
On Tue Jan 13, 2026 at 1:29 AM CET, Judith Mendez wrote:
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 /:
Thanks for testing.
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.
The patch was a bit broken, but I think I managed to apply it to
v2026.01 as it was supposed to be. (master currently doesn't boot even
SPL, I don't have time right now to debug that).
as Nishanth, mentioned, master is missing two patches [0][1]
I attached the boot log. It does boot with your patch. Also can this be
an issue with different SD cards?
Something does not quite add up,
Can you try the following 2 commands?
# mmc dev 1
# md.w 0xfa0810c
[0] https://gist.github.com/jmenti/92da6526e366e3f5cf41911724886471
[1] https://gist.github.com/jmenti/8cf589d0302248ad26da37128f622e98
~ Judith