.. _gpio-custom-dts-binding-sample:
GPIO with custom devicetree binding
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Overview
********
In Zephyr, all hardware-specific configuration is described in the devicetree.
Consequently, also GPIO pins are configured in the devicetree and assigned to a specific purpose
using a compatible.
This is in contrast to other embedded environments like Arduino, where e.g. the direction (input /
output) of a GPIO pin is configured in the application firmware.
For typical use cases like LEDs or buttons, the existing :dtcompatible:`gpio-leds` or
:dtcompatible:`gpio-keys` compatibles can be used.
This sample demonstrates how to use a GPIO pin for other purposes with a custom devicetree binding.
We assume that a load with high current demands should be switched on or off via a MOSFET. The
custom devicetree binding for the power output controlled via a GPIO pin is specified in the file
:zephyr_file:`samples/basic/custom_dts_binding/dts/bindings/power-switch.yaml`. The gate driver for
the MOSFET would be connected to the pin as specified in the ``.overlay`` file in the boards
folder.
Building and Running
********************
For each board that should be supported, a ``.overlay`` file has to be defined
in the ``boards`` subfolder.
Afterwards, the sample can be built and executed for the ``<board>`` as follows:
.. zephyr-app-commands::
:zephyr-app: samples/basic/custom_dts_binding
:board: <board>
:goals: build flash
:compact:
For demonstration purposes, some boards use the GPIO pin of the built-in LED.
Sample output
=============
The GPIO pin should be switched to active level after one second.
The following output is printed:
.. code-block:: console
Initializing pin with inactive level.
Waiting one second.
Setting pin to active level.
0b90fd5adf