rpi-config: Add option to enable One-wire interface

Signed-off-by: Khem Raj <raj.khem@gmail.com>

docs/extra-build-config.md

@@ -350,6 +350,20 @@ to `1` or enabled `PiTFT` support, or otherwise want to use another pin, use
 
      GPIO_SHUTDOWN_PIN = "25"
 
+## Enable One-Wire Interface
+
+One-wire is a single-wire communication bus typically used to connect sensors
+to the RaspberryPi. The Raspberry Pi supports one-wire on any GPIO pin, but
+the default is GPIO 4. To enable the one-wire interface explicitly set it in
+`local.conf`
+
+    ENABLE_W1 = "1"
+
+Once discovery is complete you can list the devices that your Raspberry Pi has
+discovered via all 1-Wire busses check the interface with this command
+
+`ls /sys/bus/w1/devices/`
+
 ## Manual additions to config.txt
 
 The `RPI_EXTRA_CONFIG` variable can be used to manually add additional lines to

recipes-bsp/bootfiles/rpi-config_git.bb

@@ -290,6 +290,12 @@ do_deploy() {
         echo "# Enable WM8960" >> $CONFIG
         echo "dtoverlay=wm8960-soundcard" >> $CONFIG
     fi
+
+    # W1-GPIO - One-Wire Interface
+    if [ "${ENABLE_W1}" = "1" ]; then
+        echo "# Enable One-Wire Interface" >> $CONFIG
+        echo "dtoverlay=w1-gpio" >> $CONFIG
+    fi
 }
 
 do_deploy:append:raspberrypi3-64() {