u-boot overlay.dtbo

.gitignore

*.dtbo
*.i
boot.scr

boot.cmd

# mkimage -A arm -T script -C none -n "Boot script" -d boot.cmd boot.scr

load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} ${prefix}overlay.dtbo
fdt addr ${fdtoverlay_addr_r}
fdt header get fdtoverlay_size totalsize
fdt move ${fdtcontroladdr} ${fdt_addr_r}
fdt resize ${fdtoverlay_size}
fdt apply ${fdtoverlay_addr_r}

Makefile

CPP=cpp
DTC=dtc
MKIMAGE=mkimage

LINUX=/home/matwey/lab/linux


all: boot.scr overlay-gps.dtbo overlay-i2c.dtbo

clean:
	rm -rf boot.scr overlay-gps.dtbo overlay-i2c.dtbo *.i

boot.scr: boot.cmd
	${MKIMAGE} -A arm -T script -C none -n "Boot script" -d $< $@

%.i: %.dtso
	${CPP} -x assembler-with-cpp -I ${LINUX}/include $< $@

%.dtbo: %.i
	${DTC} -@ -O dtb -o $@ $<

overlay-gps.dtso

/* cpp -x assembler-with-cpp -I /home/matwey/lab/linux/include overlay.dtso overlay.i  */
/* dtc -O dtb -o overlay.dtbo overlay.dtso */

/dts-v1/;
/plugin/;

#include <dt-bindings/gpio/gpio.h>

&pio {
	uart5_ph_pins: uart5-ph-pins {
		pins = "PH2", "PH3";
		function = "uart5";
	};

	pps_pi1_pins: pps-pi1-pins {
		pins = "PI1";
		function = "pps_pi1";		
	};
};

&{/} {
	pps_pi1: pps-pi1 {
		compatible = "pps-gpio";
		pinctrl-names = "default";
		pinctrl-0 = <&pps_pi1_pins>;
		gpios = <&pio 8 1 GPIO_ACTIVE_HIGH>; // PI1
		status = "okay";
	};
};

&uart5 {
	pinctrl-names = "default";
	pinctrl-0 = <&uart5_ph_pins>;
	status = "okay";
};

overlay-i2c.dtso

/* cpp -x assembler-with-cpp -I /home/matwey/lab/linux/include overlay.dtso overlay.i  */
/* dtc -O dtb -o overlay.dtbo overlay.dtso */

/dts-v1/;
/plugin/;

#include <dt-bindings/i2c/i2c.h>
#include <dt-bindings/gpio/gpio.h>


&i2c0 {
	status = "okay";
};

&i2c1 {
	status = "okay";
};

&{/} {
	i2c_gpio: i2c-gpio {
		compatible = "i2c-gpio";
		sda-gpios = <&pio 8 0 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; // PI0  (29)
		scl-gpios = <&pio 8 15 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; // PI15 (31)
		i2c-gpio,delay-us = <2>;        /* ~100 kHz */
		#address-cells = <1>;
		#size-cells = <0>;
		status = "okay";

		testunit@30 {
			compatible = "slave-testunit";
			reg = <(0x30 | I2C_OWN_SLAVE_ADDRESS)>;
		};
	};
};