[U-Boot] [U-Boot, 4/4] rockchip: rk3188: explicitly set vcc_sd0 pin to gpio on rk3188-radxarock

[Philipp Tomsich]

> It is good practice to make the setting of gpio-pinctrls explicitly in the
> devicetree, and in this case even necessary.
> Rockchip boards start with iomux settings set to gpio for most pins and
> while the linux pinctrl driver also implicitly sets the gpio function if
> a pin is requested as gpio that is not necessarily true for other drivers.
> 
> The issue in question stems from uboot, where the sdmmc_pwr pin is set
> to function 1 (sdmmc-power) by the bootrom when reading the 1st-stage
> loader. The regulator controlled by the pin is active-low though, so
> when the dwmmc hw-block sets its enabled bit, it actually disables the
> regulator. By changing the pin back to gpio we fix that behaviour.
> 
> [picked from the identical linux patch
> https://patchwork.kernel.org/patch/10609253/]
> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
>  arch/arm/dts/rk3188-radxarock.dts | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 

Applied to u-boot-rockchip, thanks!