135 lines
3.4 KiB
ReStructuredText
135 lines
3.4 KiB
ReStructuredText
.. _dt-inferred-bindings:
|
|
.. _dt-zephyr-user:
|
|
|
|
The ``/zephyr,user`` node
|
|
#########################
|
|
|
|
Zephyr's devicetree scripts handle the ``/zephyr,user`` node as a special case:
|
|
you can put essentially arbitrary properties inside it and retrieve their
|
|
values without having to write a binding. It is meant as a convenient container
|
|
when only a few simple properties are needed.
|
|
|
|
.. note::
|
|
|
|
This node is meant for sample code and user applications. It should not be
|
|
used in the upstream Zephyr source code for device drivers, subsystems, etc.
|
|
|
|
Simple values
|
|
*************
|
|
|
|
You can store numeric or array values in ``/zephyr,user`` if you want them to
|
|
be configurable at build time via devicetree.
|
|
|
|
For example, with this devicetree overlay:
|
|
|
|
.. code-block:: devicetree
|
|
|
|
/ {
|
|
zephyr,user {
|
|
boolean;
|
|
bytes = [81 82 83];
|
|
number = <23>;
|
|
numbers = <1>, <2>, <3>;
|
|
string = "text";
|
|
strings = "a", "b", "c";
|
|
};
|
|
};
|
|
|
|
You can get the above property values in C/C++ code like this:
|
|
|
|
.. code-block:: C
|
|
|
|
#define ZEPHYR_USER_NODE DT_PATH(zephyr_user)
|
|
|
|
DT_PROP(ZEPHYR_USER_NODE, boolean) // 1
|
|
DT_PROP(ZEPHYR_USER_NODE, bytes) // {0x81, 0x82, 0x83}
|
|
DT_PROP(ZEPHYR_USER_NODE, number) // 23
|
|
DT_PROP(ZEPHYR_USER_NODE, numbers) // {1, 2, 3}
|
|
DT_PROP(ZEPHYR_USER_NODE, string) // "text"
|
|
DT_PROP(ZEPHYR_USER_NODE, strings) // {"a", "b", "c"}
|
|
|
|
Devices
|
|
*******
|
|
|
|
You can store :ref:`phandles <dt-phandles>` in ``/zephyr,user`` if you want to
|
|
be able to reconfigure which devices your application uses in simple cases
|
|
using devicetree overlays.
|
|
|
|
For example, with this devicetree overlay:
|
|
|
|
.. code-block:: devicetree
|
|
|
|
/ {
|
|
zephyr,user {
|
|
handle = <&gpio0>;
|
|
handles = <&gpio0>, <&gpio1>;
|
|
};
|
|
};
|
|
|
|
You can convert the phandles in the ``handle`` and ``handles`` properties to
|
|
device pointers like this:
|
|
|
|
.. code-block:: C
|
|
|
|
/*
|
|
* Same thing as:
|
|
*
|
|
* ... my_dev = DEVICE_DT_GET(DT_NODELABEL(gpio0));
|
|
*/
|
|
const struct device *my_device =
|
|
DEVICE_DT_GET(DT_PROP(ZEPHYR_USER_NODE, handle));
|
|
|
|
#define PHANDLE_TO_DEVICE(node_id, prop, idx) \
|
|
DEVICE_DT_GET(DT_PHANDLE_BY_IDX(node_id, prop, idx)),
|
|
|
|
/*
|
|
* Same thing as:
|
|
*
|
|
* ... *my_devices[] = {
|
|
* DEVICE_DT_GET(DT_NODELABEL(gpio0)),
|
|
* DEVICE_DT_GET(DT_NODELABEL(gpio1)),
|
|
* };
|
|
*/
|
|
const struct device *my_devices[] = {
|
|
DT_FOREACH_PROP_ELEM(ZEPHYR_USER_NODE, handles, PHANDLE_TO_DEVICE)
|
|
};
|
|
|
|
GPIOs
|
|
*****
|
|
|
|
The ``/zephyr,user`` node is a convenient place to store application-specific
|
|
GPIOs that you want to be able to reconfigure with a devicetree overlay.
|
|
|
|
For example, with this devicetree overlay:
|
|
|
|
.. code-block:: devicetree
|
|
|
|
#include <zephyr/dt-bindings/gpio/gpio.h>
|
|
|
|
/ {
|
|
zephyr,user {
|
|
signal-gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
|
|
};
|
|
};
|
|
|
|
You can convert the pin defined in ``signal-gpios`` to a ``struct
|
|
gpio_dt_spec`` in your source code, then use it like this:
|
|
|
|
.. code-block:: C
|
|
|
|
#include <zephyr/drivers/gpio.h>
|
|
|
|
#define ZEPHYR_USER_NODE DT_PATH(zephyr_user)
|
|
|
|
const struct gpio_dt_spec signal =
|
|
GPIO_DT_SPEC_GET(ZEPHYR_USER_NODE, signal_gpios);
|
|
|
|
/* Configure the pin */
|
|
gpio_pin_configure_dt(&signal, GPIO_OUTPUT_INACTIVE);
|
|
|
|
/* Set the pin to its active level */
|
|
gpio_pin_set_dt(&signal, 1);
|
|
|
|
(See :c:struct:`gpio_dt_spec`, :c:macro:`GPIO_DT_SPEC_GET`, and
|
|
:c:func:`gpio_pin_configure_dt` for details on these APIs.)
|