[PATCH] arm64: dts: rockchip: Fix vcc_sdio regulator max voltage on Pinebook Pro

[Dang Huynh]

Hi,

On Tue, May 19, 2026 at 11:44:39AM +0200, Hugo Osvaldo Barrera wrote:
> The vcc_sdio regulator supports 1.8V to 3.4V output range according to
> its datasheet.
> 
> The current DT incorrectly limits the max voltage to 3.0V. This limit
> causes issues issues downstream with u-boot, which refuses to apply the

Just a heads up, you can run mainline U-Boot on the Pinebook Pro without
any modification.

But after looking at the datasheet for the AP6256, I can confirm that
this change matches perfectly with the recommended ratings.

Reviewed-by: Dang Huynh <dang.huynh at mainlining.org>

> out-of range value, and falls back to the minimum in that range: 1.8V.
> This is insufficient to power the SD card, so driver initialisation
> fails and booting from it does not work.
> 
> Set regulator-max-microvolt to 3400000 µV to match hardware capability.
> This matches the rk3399-orangepi for the same regulator.
> 
> Signed-off-by: Hugo Osvaldo Barrera <hugo at whynothugo.nl>
> ---
>  arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
> index b5c05928142c..f21fcdc1b49a 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
> @@ -526,7 +526,7 @@ vcc_sdio: LDO_REG4 {
>  				regulator-always-on;
>  				regulator-boot-on;
>  				regulator-min-microvolt = <1800000>;
> -				regulator-max-microvolt = <3000000>;
> +				regulator-max-microvolt = <3400000>;
>  
>  				regulator-state-mem {
>  					regulator-on-in-suspend;