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

[Judith Mendez <jm@ti.com>]

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