[PATCH v2 2/2] arm64: dts: rockchip: Enable SDIO Wi-Fi on NanoPi R2S Plus

[Deomid "rojer" Ryabkov]

Hi Heiko,

gentle ping on this one. the mmc changes have been applied for 7.5[1],
it would be nice to get the DT bits in time for 7.5 as well.

[1] https://lore.kernel.org/linux-mmc/CAPx+jO8n6Y9PWDkxurwjjfGXSiGS0KWrYK0C7=5Uqic1Gn+M7w@mail.gmail.com/

On Sat, 31 Oct 2026 at 12:47, Deomid rojer Ryabkov <rojer at rojer.me> wrote:
>
> The NanoPi R2S Plus has an M.2 E-key slot wired to the sdmmc_ext
> controller in 4-bit SDIO mode, where FriendlyElec fit an optional
> Fn-Link 6222B-SRC (Realtek RTL8822CS) module:
>
>   - SDIO signalling at a fixed 1.8V (VCC_18)
>   - WIFI_REG_ON on GPIO3_B0, 32kHz sleep clock from the RK805 CLKOUT2
>
> Enable the controller and add the power sequence. The SDIO pins need
> 8mA drive strength for SDR104 tuning to succeed, as in the vendor
> device tree [1]; with the SoC default of 4mA no sample phase works.
>
> On boards without the module the controller gives up after about 0.2s
> ("mmc2: Failed to initialize a non-removable card"); nothing else is
> affected.
>
> With the mmc core change for the module's CMD11 handling at a fixed
> 1.8V [2], the module is tuned to SDR104 at 150 MHz and works with the
> rtw88_8822cs driver; without it, it runs in high-speed mode at 50 MHz.
>
> [1] https://github.com/friendlyarm/kernel-rockchip/blob/9238df9d21e835bba35c8ba5248784387936cb2e/arch/arm64/boot/dts/rockchip/rk3328-nanopi-r2-rev24.dts#L144-L172
> [2] https://lore.kernel.org/linux-mmc/20261030142224.3183407-1-rojer@rojer.me/
> Reviewed-by: Shawn Lin <shawn.lin at rock-chips.com>
> Signed-off-by: Deomid rojer Ryabkov <rojer at rojer.me>
> ---
>  .../dts/rockchip/rk3328-nanopi-r2s-plus.dts   | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk3328-nanopi-r2s-plus.dts b/arch/arm64/boot/dts/rockchip/rk3328-nanopi-r2s-plus.dts
> index 6ba4a74cb1f..a25421f5851 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3328-nanopi-r2s-plus.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3328-nanopi-r2s-plus.dts
> @@ -17,6 +17,15 @@ / {
>         aliases {
>                 mmc1 = &emmc;
>         };
> +
> +       sdio_pwrseq: sdio-pwrseq {
> +               compatible = "mmc-pwrseq-simple";
> +               clocks = <&rk805 1>;
> +               clock-names = "ext_clock";
> +               pinctrl-names = "default";
> +               pinctrl-0 = <&wifi_reg_on_h>;
> +               reset-gpios = <&gpio3 RK_PB0 GPIO_ACTIVE_LOW>;
> +       };
>  };
>
>  &emmc {
> @@ -34,3 +43,49 @@ &io_domains {
>         vccio4-supply = <&vcc_io_33>;
>         vccio6-supply = <&vcc_18>;
>  };
> +
> +&pinctrl {
> +       wifi {
> +               wifi_reg_on_h: wifi-reg-on-h {
> +                       rockchip,pins = <3 RK_PB0 RK_FUNC_GPIO &pcfg_pull_none>;
> +               };
> +       };
> +};
> +
> +/*
> + * SDR104 tuning fails with the default 4mA drive strength, use 8mA like the
> + * vendor device tree.
> + */
> +&sdmmc0ext_bus4 {
> +       rockchip,pins =
> +               <3 RK_PA4 3 &pcfg_pull_up_8ma>,
> +               <3 RK_PA5 3 &pcfg_pull_up_8ma>,
> +               <3 RK_PA6 3 &pcfg_pull_up_8ma>,
> +               <3 RK_PA7 3 &pcfg_pull_up_8ma>;
> +};
> +
> +&sdmmc0ext_clk {
> +       rockchip,pins = <3 RK_PA2 3 &pcfg_pull_none_8ma>;
> +};
> +
> +&sdmmc0ext_cmd {
> +       rockchip,pins = <3 RK_PA0 3 &pcfg_pull_up_8ma>;
> +};
> +
> +/* Optional M.2 E-key SDIO Wi-Fi module (Fn-Link 6222B-SRC, RTL8822CS) */
> +&sdmmc_ext {
> +       bus-width = <4>;
> +       cap-sd-highspeed;
> +       cap-sdio-irq;
> +       keep-power-in-suspend;
> +       mmc-pwrseq = <&sdio_pwrseq>;
> +       no-mmc;
> +       no-sd;
> +       non-removable;
> +       pinctrl-names = "default";
> +       pinctrl-0 = <&sdmmc0ext_clk &sdmmc0ext_cmd &sdmmc0ext_bus4>;
> +       sd-uhs-sdr104;
> +       vmmc-supply = <&vcc_io_33>;
> +       vqmmc-supply = <&vcc_18>;
> +       status = "okay";
> +};
> --
> 2.53.0
>


-- 
Deomid "rojer" Ryabkov
rojer at rojer.me