GPIO pin configuration using Devicetree

RE: GPIO pin configuration using Devicetree

Vidar Berg — Wed, 12 Jul 2023 13:06:04 GMT

My coworker Marte has posted a sample to demonstrate how you can add custom bindings on GitHub. You can find it here: https://github.com/martelmy/NCS_examples/tree/main/devicetree/devicetree_custom_device. Additionally, there is a similar sample available in Zephyr: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/samples/basic/custom_dts_binding/README.html.

Optionally, you can create an out-of-tree driver as shown in this sample: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/samples/application_development/out_of_tree_driver/README.html.

RE: GPIO pin configuration using Devicetree

piotrosiotr — Wed, 12 Jul 2023 12:50:35 GMT

OK, thank you, that works perfectly for me. But I've got another question: what if I want to create a custom devicetree binding for a "compatible" property? How to deal with it? For example, I have a shift register on my board and I want to declare in dts file and use it like a usual gpio pin. Should I create a custom driver for it? In which way I should use "compatible" property?

RE: GPIO pin configuration using Devicetree

Vidar Berg — Fri, 07 Jul 2023 11:42:08 GMT

Hi,

You were on the right track by using the device tree to assign the control pin. However, in order to define a new node as you did, you also need to select a suitable device tree binding by using the 'compatible' property.

Since you will be using the output to control power, it would make sense to select the 'regulator-fixed'' binding and add CONFIG_REGULATOR=y to your prj.conf file. This will enable the Regulator subsystem in your application.

Here is an example I made for this:

devzone.nordicsemi.com/.../regulator_5F00_example.zip

Best regards,

Vidar