Sample with button and power management

main.c

/*
 * Copyright (c) 2020 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */

#include <zephyr.h>
#include <device.h>
#include <drivers/gpio.h>
#include <string.h>
#include <stdio.h>
#include <devicetree.h>

#define SW0 DT_ALIAS(sw0)
#define LED0 DT_ALIAS(led0)
#define LED1 DT_ALIAS(led1)

static struct device *cons;
static struct device *led0;
static struct device *led1;
static struct device *sw0;
static struct gpio_callback sw0_data;

static const char *now_str(void)
{
	static char buf[16]; /* ...HH:MM:SS.MMM */
	uint32_t now = k_uptime_get_32();
	unsigned int ms = now % MSEC_PER_SEC;
	unsigned int s;
	unsigned int min;
	unsigned int h;

	now /= MSEC_PER_SEC;
	s = now % 60U;
	now /= 60U;
	min = now % 60U;
	now /= 60U;
	h = now;

	snprintf(buf, sizeof(buf), "%u:%02u:%02u.%03u",
		 h, min, s, ms);
	return buf;
}

void
button_pressed(struct device *dev, struct gpio_callback *cb,
	       uint32_t pins)
{
	static uint32_t count;

	++count;
	gpio_pin_toggle(led1, DT_GPIO_PIN(LED1, gpios));

	printk("%s button pressed %u\n", now_str(), count);
	if ((count % 8) == 4) {
		printk("Turning off console\n");
		device_set_power_state(cons, DEVICE_PM_LOW_POWER_STATE, NULL, NULL);
	} else if ((count % 8) == 0) {
		device_set_power_state(cons, DEVICE_PM_ACTIVE_STATE, NULL, NULL);
		printk("Turned on console\n");
	}
}

void
main(void)
{
	int ret;

	cons = device_get_binding(DT_LABEL(DT_CHOSEN(zephyr_console)));
	led0 = device_get_binding(DT_GPIO_LABEL(LED0, gpios));
	led1 = device_get_binding(DT_GPIO_LABEL(LED1, gpios));
	sw0 = device_get_binding(DT_GPIO_LABEL(SW0, gpios));

	printk("Device started %p %p %p %p!\n", cons, led0, led1, sw0);

	printk("Starting Button Interrupt!\n");

	gpio_init_callback(&sw0_data, button_pressed,
			   BIT(DT_GPIO_PIN(SW0, gpios)));

	ret = gpio_pin_configure(led0, DT_GPIO_PIN(LED0, gpios),
				 DT_GPIO_FLAGS(LED0, gpios)
				 | GPIO_OUTPUT_ACTIVE);
	if (ret == 0) {
		ret = gpio_pin_configure(led1, DT_GPIO_PIN(LED1, gpios),
					 DT_GPIO_FLAGS(LED1, gpios)
					 | GPIO_OUTPUT_INACTIVE);
	}

	if (ret == 0) {
		ret = gpio_pin_configure(sw0, DT_GPIO_PIN(SW0, gpios),
					 DT_GPIO_FLAGS(SW0, gpios) | GPIO_INPUT);
	}

	if (ret == 0) {
		ret = gpio_pin_interrupt_configure(sw0, DT_GPIO_PIN(SW0, gpios),
						   GPIO_INT_EDGE_TO_ACTIVE);
	}
	if (ret == 0) {
		gpio_add_callback(sw0, &sw0_data);
	}
	printk("%s Setup: %d\n", now_str(), ret);

	while (1) {
		printk("%s looping\n", now_str());
		k_sleep(K_SECONDS(1));
		gpio_pin_toggle(led0, DT_GPIO_PIN(LED0, gpios));
	}
}

prj.conf

CONFIG_SYS_POWER_MANAGEMENT=y
CONFIG_DEVICE_POWER_MANAGEMENT=y
CONFIG_GPIO=y