[PATCH] arm64: dts: amlogic: meson-sm1-odroid: let the SD card be powered down

[sashiko-bot at kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] dts: amlogic: SD card backpowering due to unpowered VMMC with powered VQMMC
--

commit 4f4437abf57138f198c4057f670c6a5c23c3af61
Author: Igor Velkov <iav at iav.lv>

arm64: dts: amlogic: meson-sm1-odroid: let the SD card be powered down

This commit drops the regulator-always-on property from the SD card's VMMC
supply (tflash_vdd) to allow it to be powered down during a warm reboot.

Fixes: 326e57518b0d ("arm64: dts: meson-sm1: add support for Hardkernel ODROID-C4")

> diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
> index e6f02d738a21f..7dbc75bfaea25 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
> @@ -38,7 +38,6 @@ tflash_vdd: regulator-tflash-vdd {
>  		gpio = <&gpio_ao GPIOAO_3 GPIO_OPEN_DRAIN>;
>  		enable-active-high;
>  		regulator-boot-on;
> -		regulator-always-on;
>  	};
>  
>  	tf_io: gpio-regulator-tf-io {

[Severity: High]
Does removing regulator-always-on from tflash_vdd cause the SD card to be
backpowered during shutdown or warm reboot?

Looking at the sd_emmc_b node, tf_io is configured as the vqmmc-supply
alongside tflash_vdd:

&sd_emmc_b {
	...
	vmmc-supply = <&tflash_vdd>;
	vqmmc-supply = <&tf_io>;
};

However, the tf_io node still retains its regulator-always-on property:

	tf_io: gpio-regulator-tf-io {
		...
		enable-active-high;
		regulator-boot-on;
		regulator-always-on;
	};

When mmc_power_off() disables VMMC (tflash_vdd), VMMC will drop to 0V.
Because tf_io is always-on, the regulator core will ignore the request to
disable VQMMC.

Can this leave the I/O lines driven while the core power is removed, leading
to an unpowered VMMC with a powered VQMMC?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261003-hc4-sd-power-off-v1-1-f7ffba01b348@iav.lv?part=1