Re: [PATCH 0/2] arm64: dts: imx8m-kontron: Revert reading SD_VSEL signal

[Frieder Schrempf <frieder.schrempf@kontron.de>]

On 01.04.26 04:05, Peng Fan (OSS) wrote:
> When MUX is configured as SDHC VSELECT, enabling SION is not able
> to read back the SD_VSEL value. SION is used for force input path,
> not to redirect the PAD value to GPIO(the other mux).
> 
> This has been confirmed by reading i.MX8MP RTL. we have not check
> i.MX8MM RTL, but it should be same.

It seems like you are right and I misinterpreted the documentation and
also misinterpreted my test results. So I was probably basing my work on
wrong assumptions.

> 
> Not sure whether need to add Fixes commit for the patches, just revert
> patches.

This was introduced in 6.15. I would like to add Fixes tags for the
reverts. And can we add patches in this series that switch to GPIO
control as done in [1] and also tag them as fixes? This should allow to
read back the correct voltage from the regulator.

> 
> For the U-Boot support, either drop vqmmc-supply or switch to use gpio
> control to replace vselect control.
> 
> And below patch should also be revisited.

I think we can revert this, too.

> commit 3ce6f4f943ddd9edc03e450a2a0d89cb025b165b
> Author: Frieder Schrempf <frieder.schrempf@kontron.de>
> Date:   Wed Dec 18 16:27:27 2024 +0100
> 
>     regulator: pca9450: Fix control register for LDO5
> 
> To supporting read back signal, need the MUX set as GPIO and support
> in/out, not set mux as VSELECT.
> 
> TBH: I have not test setting MUX as GPIO, anyway we need to fix DT.

If we mux as GPIO, then we don't need to read back. I think in this case
the best solution is the one used in [1].

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=5245dc5

> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
> Peng Fan (2):
>       Revert "arm64: dts: imx8mm-kontron: Add support for reading SD_VSEL signal"
>       Revert "arm64: dts: imx8mp-kontron: Add support for reading SD_VSEL signal"
> 
>  arch/arm64/boot/dts/freescale/imx8mm-kontron-bl.dts     | 10 +++-------
>  arch/arm64/boot/dts/freescale/imx8mm-kontron-osm-s.dtsi |  7 +++----
>  arch/arm64/boot/dts/freescale/imx8mp-kontron-osm-s.dtsi |  7 +++----
>  3 files changed, 9 insertions(+), 15 deletions(-)
> ---
> base-commit: 3b058d1aeeeff27a7289529c4944291613b364e9
> change-id: 20260329-imx8m-ldo5-90e369066213
> 
> Best regards,