Using the DS2482 one wire master chips on i2c bus via the kernels w1-gpio-ds2482 driver

For this test I have hooked up a temperature sensor to the 1W ports

First Let's check the bus master devices have all been detected :

root@raspberrypi:~# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- 0c -- -- --
10: -- -- -- -- -- -- -- -- 18 19 -- -- -- -- -- --
20: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- 2f
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- UU -- -- -- -- -- --
50: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

This looks good as the 1-Wire bus masters have been detected

1W bus 1 => 0x19
1W bus 0 => 0x18

Create a device tree overlay for the DS2482 chips in /root/device-tree/ds2482.dts

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835";

    fragment@0 {
        target = <&i2c1>;
        __overlay__ {
            status = "okay";
            #address-cells = <1>;
            #size-cells = <0>;

            w1_master_0: ds2482@18 {
                compatible = "maxim,ds2482";
                reg = <0x18>;
                status = "okay";
            };

            w1_master_1: ds2482@19 {
                compatible = "maxim,ds2482";
                reg = <0x19>;
                status = "okay";
            };
        };
    };
};

Compile the overlay:

sudo dtc -@ -I dts -O dtb -o /boot/overlays/ds2482.dtbo /root/device-tree/ds2482.dts

Enable the required kernel module:

echo "w1-gpio-ds2482" | sudo tee -a /etc/modules

Add the overlay to boot config:

echo "dtoverlay=ds2482" | sudo tee -a /boot/config.txt

Reboot the unit

sudo reboot

After reboot, check your 1-Wire devices are detected:

ls /sys/bus/w1/devices/

You should see your bus masters and any connected devices, for example:

root@raspberrypi:~# ls /sys/bus/w1/devices/ -l
total 0
lrwxrwxrwx 1 root root 0 Feb  4 13:57 28-00000adde5c9 -> ../../../devices/w1_bus_master1/28-00000adde5c9
lrwxrwxrwx 1 root root 0 Feb  4 13:34 28-00000adeacb6 -> ../../../devices/w1_bus_master2/28-00000adeacb6
lrwxrwxrwx 1 root root 0 Feb  4 13:20 w1_bus_master1 -> ../../../devices/w1_bus_master1
lrwxrwxrwx 1 root root 0 Feb  4 13:20 w1_bus_master2 -> ../../../devices/w1_bus_master2

To read the temperature from a DS18B20 sensor:

cat /sys/bus/w1/devices/28-00000adeacb6/temperature
27750    # This equals 27.75°C

To trigger a new bus scan for newly connected devices:

echo 1 > /sys/bus/w1/devices/w1_bus_master1/w1_master_search
echo 1 > /sys/bus/w1/devices/w1_bus_master2/w1_master_search

Note that this kernel-based approach is more reliable than OWFS and doesn't require any additional services to be running.