Re: [PATCH v3] arm64: dts: rockchip: enable SD UHS-I on Firefly-RK3399

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] arm64: dts: rockchip: vcc_sdio 3.0V cap on rk3399-firefly
  logs KERN_ERR
--

commit 7bc8a98bc2811aebd6d7fda8a2601a2bbf060220
Author: Yaozhong Li <yaozhonguwl@gmail.com>

arm64: dts: rockchip: enable SD UHS-I on Firefly-RK3399

This commit adds the vcc_sd regulator for the SD card slot on
Firefly-RK3399, updates the power supply assignments for sdio0 and
sdmmc, and enables SD UHS-I SDR104 on sdmmc.

> diff --git a/arch/arm64/boot/dts/rockchip/rk3399-firefly.dts b/arch/arm64/boot/dts/rockchip/rk3399-firefly.dts
> index 0568dfa140b32..03858a472d124 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399-firefly.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3399-firefly.dts
> @@ -233,6 +233,19 @@ vcc5v0_typec: regulator-vcc5v0-typec {
>  		vin-supply = <&vcc_sys>;
>  	};
>  
> +	vcc_sd: regulator-vcc-sd {
> +		compatible = "regulator-fixed";
> +		enable-active-high;
> +		gpio = <&gpio4 RK_PD6 GPIO_ACTIVE_HIGH>;
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&vcc_sd_en>;
> +		regulator-name = "vcc_sd";
> +		regulator-boot-on;
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +		vin-supply = <&vcc3v3_sys>;
> +	};
> +
>  	vcc_sys: regulator-vcc-sys {
>  		compatible = "regulator-fixed";
>  		regulator-name = "vcc_sys";

[ ... ]

> @@ -804,6 +823,9 @@ &sdmmc {
>  	max-frequency = <150000000>;
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&sdmmc_clk &sdmmc_cmd &sdmmc_bus4>;
> +	sd-uhs-sdr104;
> +	vmmc-supply = <&vcc_sd>;
> +	vqmmc-supply = <&vcc_sdio>;
>  	status = "okay";
>  };

[Severity: Medium]
Should vcc_sdio's regulator-max-microvolt be raised to 3300000 to match
vcc_sd?

In this file, vcc_sdio is capped at 3.0V:

arch/arm64/boot/dts/rockchip/rk3399-firefly.dts:
	vcc_sdio: LDO_REG4 {
		regulator-name = "vcc_sdio";
		regulator-always-on;
		regulator-boot-on;
		regulator-min-microvolt = <1800000>;
		regulator-max-microvolt = <3000000>;

Because vcc_sd is 3.3V, mmc_power_up() -> mmc_set_initial_signal_voltage()
-> mmc_regulator_set_vqmmc() calls regulator_set_voltage_triplet(vcc_sdio,
3000000, 3300000, 3600000) for 3.3V signaling.  The first attempt in
regulator_set_voltage_triplet() requests 3300000..3600000 uV, which
regulator_check_voltage() clamps to vcc_sdio's 3000000 uV maximum and
rejects with:

  vcc_sdio: unsupportable voltage range: 3300000-3000000uV

before falling back to 3.0V and leaving the IO supply at 3.0V while the
card supply is at 3.3V.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261106061835.1316-1-yaozhonguwl@gmail.com?part=1