How to manually edit devicetree files

If you want to manually edit the devicetree files directly in the Editor instead of using the Devicetree Visual Editor, you can follow the steps described below and take advantage of the Devicetree language support.

Make sure to create an overlay file in case you need one before you start editing it. Directly editing .dts or .overlay files that come with the nRF Connect SDK installation may have unintended consequences to other boards or to applications that use the same board.

How to add a node in overlay files

Complete the following steps:

1. Open the .overlay file you want to edit.
2. Press Ctrl-Space to start the autocompletion feature.
   A list of the available nodes appears.
3. Click the name of the node to complete the autocompletion.

For detailed information about writing property values, see Zephyr's documentation.

Example: Adding a dimmable LED

In this example, we will add a dimmable LED to the board. Zephyr provides a generic binding for PWM LED controllers, named pwm-leds. Bindings are type definitions for devicetree nodes, defining which properties the node supports and what values they expect.

Bindings are specified by setting the compatible property within the node where they are supposed to be used, which in our example is the PWM LED controller node (pwmleds). In this pwmleds controller node, we can add nodes for each LED. The pwm-leds binding defines the properties of its child nodes as well, so the properties for LED nodes led_pwm_1 and led_pwm_2 can also be auto-completed.

Complete the following steps:

1. Add the controller node pwmleds under the root node in devicetree.
2. Add the pwm-leds binding for the driver to pick up.
3. Add LEDs as child nodes on the pwmleds controller node, with pwms and label properties.

4. Make sure the pwms property of the phandle-array type points to a PWM instance. The PWM instance takes the pin number as its only parameter. In this example, we are using pins 6 and 7 on the GPIO port 0 (&pwm0).

   Dimmable LEDs in .dts - steps 1 to 4

   / { // Devicetree root
       // ...
       pwmleds { // Controller node
               compatible = "pwm-leds"; // Compatible binding
               led_pwm_1 {
                       pwms = <&pwm0 6>; // Pin assigned to GPIO port 0 for the LED 1
                       label = "PWM LED 1";
               };
   
   
               led_pwm_2 {
                       pwms = <&pwm0 7>; // Pin assigned to GPIO port 0 for the LED 2
                       label = "PWM LED 2";
               };
       };
   };
   

5. Enable the referenced PWM0 node by setting status = "okay" and configuring the node's channels. For this, we use the &pwm0 node label reference on the root of the file:

   Dimmable LEDs in .dts - step 5 (Enabling PWM0)

   &pwm0 {
       status = "okay"; // Status
       ch0-pin = <6>; // Pin assignment for channel 0
       ch1-pin = <7>; // Pin assignment for channel 1
   };
   

6. Enable the LED PWM driver in Kconfig by adding CONFIG_LED_PWM=y in the board's prj.conf file.

How to add missing required properties

The extension includes a code action to add all required properties missing from a devicetree node. When applicable, a button with a light bulb icon appears next to the selected node in the Editor.

To add the missing required property:

1. Click on the property icon.
2. Click on Add required properties.

See the following GIF for a preview of these steps.

How to copy C identifiers

You can copy references to a node or property from a devicetree file and paste them into your C code.

Copying from a devicetree file

To copy C identifiers directly from a devicetree file:

1. Select the string in the file.

2. Right-click the string label.
   The contextual menu appears.

   

3. Click Copy C Identifier.

If the selected symbol has a corresponding C macro, like DT_PROP(DT_NODELABEL(adc), label), it will be copied to the clipboard. A message shows up in the Status Bar with the copied string.

Copying C identifier of a node

To copy the C identifier of a node:

1. Expand the appropriate section in the Devicetree View.
2. Hover your mouse over the node you want to copy.
3. Click on the More actions... menu icon.
4. Click on Copy C Identifier of Node.