arm64: dts: rockchip: Lower SD card speed on rk3399 Pinebook Pro

MicroSD card slot in the Pinebook Pro is located on a separate
daughterboard that's connected to the mainboard using a rather
long flat cable.  The resulting signal degradation causes many
perfectly fine microSD cards not to work in the Pinebook Pro,
which is a common source of frustration among the owners.

Changing the mode and lowering the speed reportedly fixes this
issue and makes many microSD cards work as expected.

Co-developed-by: Dragan Simic <dragan.simic@gmail.com>
Signed-off-by: Dragan Simic <dragan.simic@gmail.com>
Tested-by: JR Gonzalez <jrg@scientiam.org>
Signed-off-by: Dan Johansen <strit@manjaro.org>
Link: https://lore.kernel.org/r/20230305104730.15849-1-strit@manjaro.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
index 194e48c755f6bc19d33f0736a0423d6205859450..54bb0398128f0e9cf1b91dc4ebacf77c097af35a 100644 (file)
--- a/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts
@@ -943,7 +943,7 @@
        disable-wp;
        pinctrl-names = "default";
        pinctrl-0 = <&sdmmc_clk &sdmmc_cmd &sdmmc_bus4>;
-       sd-uhs-sdr104;
+       sd-uhs-sdr50;
        vmmc-supply = <&vcc3v0_sd>;
        vqmmc-supply = <&vcc_sdio>;
        status = "okay";