Re: [PATCH v2] Revert "mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch"

[Judith Mendez <jm@ti.com>]

Hi all,

On 1/27/25 2:12 PM, Josua Mayer wrote:
> This reverts commit 941a7abd4666912b84ab209396fdb54b0dae685d.
> 
> This commit uses presence of device-tree properties vmmc-supply and
> vqmmc-supply for deciding whether to enable a quirk affecting timing of
> clock and data.
> The intention was to address issues observed with eMMC and SD on AM62
> platforms.
> 
> This new quirk is however also enabled for AM64 breaking microSD access
> on the SolidRun HimmingBoard-T which is supported in-tree since v6.11,
> causing a regression. During boot microSD initialization now fails with
> the error below:
> 
> [    2.008520] mmc1: SDHCI controller on fa00000.mmc [fa00000.mmc] using ADMA 64-bit
> [    2.115348] mmc1: error -110 whilst initialising SD card
> 
> The heuristics for enabling the quirk are clearly not correct as they
> break at least one but potentially many existing boards.
> 
> Revert the change and restore original behaviour until a more
> appropriate method of selecting the quirk is derived.


Somehow I missed these emails, apologies.

Thanks for reporting this issue Josua.

We do need this patch for am62x devices since it fixes timing issues
with a variety of SD cards on those boards, but if there is a
regression, too bad, patch had to be reverted.

I will look again into how to implement this quirk, I think using the
voltage regulator nodes to discover if we need this quirk might not have
been a good idea, based on your explanation. I believe I did test the
patch on am64x SK and am64x EVM boards and saw no boot issue there,
so the issue seems related to the voltage regulator nodes existing in DT
(the heuristics for enabling the quirk) as you call it.

Again, thanks for reporting, will look into fixing this issue for am62x
again soon.

~ Judith