Re: [PATCH v2 06/10] ARM: tegra: tf701t: Tune MMC devices

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Moving the MicroSD card power control to `power-gpios` and a shared regulator breaks MMC power cycling, preventing UHS-I (1.8V) error recovery.
--

--- Patch [6]: [PATCH v2 06/10] ARM: tegra: tf701t: Tune MMC devices ---
commit 08fae6eaa1d66420a7beb84b307b949d0eb99b35
Author: Svyatoslav Ryhel <clamor95@gmail.com>

ARM: tegra: tf701t: Tune MMC devices

This commit adds SDR104 mode to WiFi SDIO and uSD device nodes, removes
mmc-ddr-1_8v, and improves power sequences. The uSD card configuration is
adjusted to mimic the downstream kernel setup.

> diff --git a/arch/arm/boot/dts/nvidia/tegra114-asus-tf701t.dts b/arch/arm/boot/dts/nvidia/tegra114-asus-tf701t.dts
> index 83f8dd84d28a2..3de5c84d5f009 100644
> --- a/arch/arm/boot/dts/nvidia/tegra114-asus-tf701t.dts
> +++ b/arch/arm/boot/dts/nvidia/tegra114-asus-tf701t.dts

[ ... ]

> @@ -2396,14 +2394,18 @@ wifi@1 {
>  	/* MicroSD card */
>  	mmc@78000400 {
>  		status = "okay";
> -
>  		bus-width = <4>;
> +
>  		cd-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_LOW>;
> +		power-gpios = <&gpio TEGRA_GPIO(K, 1) GPIO_ACTIVE_HIGH>;
> +
> +		sd-uhs-ddr50;
> +		sd-uhs-sdr104;
>  
>  		nvidia,default-tap = <0x3>;
>  		nvidia,default-trim = <0x3>;
>  
> -		vmmc-supply = <&vdd_2v9_usd>;
> +		vmmc-supply = <&vcore_emmc>;

[Severity: High]
Does replacing the dynamic regulator with a static power-gpios property and a
shared upstream regulator prevent the MMC subsystem from cycling VDD?

During an MMC power cycle (e.g., error recovery or system reset), the MMC core
attempts to cycle vmmc-supply. However, vmmc-supply is now the shared
vcore_emmc, which remains on because the non-removable eMMC holds a reference.

Meanwhile, the actual load switch for the MicroSD slot (TEGRA_GPIO(K, 1)) is
permanently held high during probe and never toggled:

drivers/mmc/host/sdhci-tegra.c:sdhci_tegra_probe() {
    ...
    tegra_host->power_gpio = devm_gpiod_get_optional(&pdev->dev, "power",
                                                     GPIOD_OUT_HIGH);
    ...
}

If UHS-I 1.8V mode negotiation fails, or if a soft reboot occurs while the
card is in 1.8V mode, the card will remain stuck expecting 1.8V signalling.
The host will revert to 3.3V (or 2.9V) and fail to initialize the card until
a hard cold boot.

>  		vqmmc-supply = <&vddio_usd>;
>  	};

[ ... ]

> @@ -2608,17 +2611,6 @@ hdmi_5v0_sys: regulator-hdmi {
>  		vin-supply = <&vdd_smps10_out2>;
>  	};
>  
> -	vdd_2v9_usd: regulator-vdd-usd {
> -		compatible = "regulator-fixed";
> -		regulator-name = "vdd_sd_slot";
> -		regulator-min-microvolt = <2900000>;
> -		regulator-max-microvolt = <2900000>;
> -		regulator-boot-on;
> -		gpio = <&gpio TEGRA_GPIO(K, 1) GPIO_ACTIVE_HIGH>;
> -		enable-active-high;
> -		vin-supply = <&vcore_emmc>;
> -	};
> -

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260721101059.451699-1-clamor95@gmail.com?part=6