mmc_spi.dts

/*
compiled it with:
dtc -@ -I dts -O dtb -o mmc_spi.dtbo mmc_spi.dts
load with:
sudo dtoverlay -d . mmc_spi
*/
/dts-v1/;
/plugin/;

/ {
   compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";

   fragment@0 {
                target = <&spidev0>;
                __overlay__ {
                        status = "disabled";
                };
   };

   fragment@1 {
      target = <&spi0>;
      __overlay__ {
         // needed to avoid dtc warning
         #address-cells = <1>;
         #size-cells = <0>;
         status = "okay";
         sd1: sd1@0 {
                reg = <0>;
                status = "okay";
                compatible = "mmc-spi-slot";
                voltage-ranges = <3000 3500>;
                spi-max-frequency = <8000000>;
         };
      };
   };
};