Overlays on meson64 are tough and not well supported in Armbian.
Even different Amlogic SoCs pinctrl are not compatible between them.
I've took a quick look at my OdroidN2, and it seems that GPIOX_7 is pin 72.
So, I've created a quick overlay source provided below, although I didn't attached any DS18B20, it seems to work :
/dts-v1/;
/ {
compatible = "amlogic,meson-gxbb";
fragment@0 {
target-path = [ 2f 00 ];
__overlay__ {
onewire@0 {
compatible = "w1-gpio";
pinctrl-names = "default";
gpios = < 0xffffffff 0x48 0x06 >;
status = "okay";
phandle = < 0x01 >;
};
};
};
__symbols__ {
w1 = "/fragment@0/__overlay__/onewire@0";
};
__fixups__ {
gpio = "/fragment@0/__overlay__/onewire@0:gpios:0";
};
};
Executing the command "cat /sys/kernel/debug/gpio" provided me the following output, and as we can see the w1 bus appeared :
gpiochip1: GPIOs 412-426, parent: platform/ff800000.sys-ctrl:pinctrl@14, aobus-banks:
gpio-420 ( |regulator-tflash_vdd) out hi
gpio-421 ( |TF_IO ) out lo
gpio-423 ( |n2:blue ) out lo
gpiochip0: GPIOs 427-511, parent: platform/ff634400.bus:pinctrl@40, periphs-banks:
gpio-442 ( |PHY reset ) out hi ACTIVE LOW
gpio-447 ( |usb-hub-reset ) in hi
gpio-448 ( |regulator-hub_5v ) out hi
gpio-449 ( |regulator-usb_pwr_en) out lo
gpio-464 ( |reset ) out hi ACTIVE LOW
gpio-474 ( |cd ) in hi ACTIVE LOW
gpio-499 ( |onewire@0 ) out hi
Hoping this helped ...