pi2 spi.dts

spi.dts

#include <dt-bindings/pinctrl/bcm2835.h>
/dts-v1/;
/plugin/;

/ {
	compatible = "raspberrypi,2-model-b";
	fragment@0 {
		target = <&spi>;
		__overlay__ {
			cs-gpios = <&gpio 8 1>, <&gpio 7 1>;
			status = "okay";
			pinctrl-names = "default";
			pinctrl-0 = <&spi0_pins &spi0_cs_pins>;
			#address-cells = <1>;
			#size-cells = <0>;
			/*
			spidev@0 {
				reg = <0>;	// CE0
				spi-max-frequency = <500000>;
				compatible = "spidev";
			};

			spidev@1 {
				reg = <1>;	// CE1
				spi-max-frequency = <500000>;
				compatible = "spidev";
			};
			*/
		};
	};
	// alternatively we could say
	/* target = <&gpio>;
	   __overlay__ {
	     pinctrl-0 = <>;
	   }
	*/
	// to not assign any pins by default
	// or just pinctrl-0 = <&gpioout>;
	// like.. what's the point?
	fragment@1 {
		target = <&gpio>;
		__overlay__ {
			// By default this pinctrl-0 = <&gpioout &alt0 &i2s_alt0>;
			// keep juts gpioout which is only pin 6
			pinctrl-0 = <&gpioout>;
		};
	};

	fragment@2 {
		target = <&gpio>;
		__overlay__ {
			spi0_pins: spi0_pins {
				brcm,pins = <9 10 11>;
				brcm,function = <BCM2835_FSEL_ALT0>;
			};
			spi0_cs_pins: spi0_cs_pins {
				brcm,pins = <8 7>;
				brcm,function = <BCM2835_FSEL_GPIO_OUT>;
			};
		};
	};
};