The 3.3V line coming from the SDMMC regulator is required for USB on the CM4IO board. Without it, the USB mux (U13 in the CM4IO schematic[1]) that's used likely remains unpowered, and no USB devices show up. The consequence of this was the behaviour of an inserted SD card allowing USB to work, while pulling it out turned off all USB devices. [1]: https://datasheets.raspberrypi.com/cm4io/cm4io-datasheet.pdf Fixes: 5859b5a9c3ac ("arm64: dts: rockchip: add SoQuartz CM4IO dts") Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@xxxxxxxxx> --- arch/arm64/boot/dts/rockchip/rk3566-soquartz-cm4.dts | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm64/boot/dts/rockchip/rk3566-soquartz-cm4.dts b/arch/arm64/boot/dts/rockchip/rk3566-soquartz-cm4.dts index 263ce40770dd..88a61fa8a95c 100644 --- a/arch/arm64/boot/dts/rockchip/rk3566-soquartz-cm4.dts +++ b/arch/arm64/boot/dts/rockchip/rk3566-soquartz-cm4.dts @@ -135,6 +135,12 @@ &sdmmc0 { }; &sdmmc_pwr { + /* + * USB also needs this regulator to work on this board, so just enable + * it unconditionally. + */ + regulator-always-on; + regulator-boot-on; regulator-min-microvolt = <3300000>; regulator-max-microvolt = <3300000>; status = "okay"; -- 2.39.1
