samples: sensor: sm351lt: Add new SM351LT sensor sample

#

# Copyright (c) 2020, Laird Connectivity

#

# SPDX-License-Identifier: Apache-2.0

#

cmake_minimum_required(VERSION 3.13.1)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(sm351lt)

FILE(GLOB app_sources src/*.c)

target_sources(app PRIVATE ${app_sources})

.. _sm351lt:

SM351LT: Magnetoresistive Sensor Example

########################################

Overview

********

This sample application periodically polls an SM351LT magnetoresistive sensor

and displays if a magnet near to the sensor, via the console.

Requirements

************

This sample uses the Honeywell SM351LT sensor.

References

**********

For more information about the SM351LT magnetoresistive sensor see

https://sensing.honeywell.com/SM351LT-low-power

Building and Running

********************

The SM351LT (or compatible) sensors are available on the following boards:

* :ref:`bt510`

Building on bt510

==================

:ref:`bt510` includes a Honeywell SM351LT magnetoresistive sensor.

.. zephyr-app-commands::

   :zephyr-app: samples/sensor/sm351lt

   :board: bt510

   :goals: build flash

   :compact:

Sample Output

=============

.. code-block:: console

    Polling at 0.5 Hz

    #1 @ 6 ms: 1

    #2 @ 2007 ms: 0

    #3 @ 4009 ms: 0

    #4 @ 6010 ms: 1

    #5 @ 8012 ms: 1

CONFIG_STDOUT_CONSOLE=y

CONFIG_GPIO=y

CONFIG_SENSOR=y

CONFIG_SM351LT=y

sample:

  name: SM351LT Magnetoresistive Sensor Example

tests:

  sample.sensor.sm351lt:

    harness: sensor

    tags: samples sensor

    depends_on: gpio sm351lt

/*

 * Copyright (c) 2020 Laird Connectivity

 * Based on code by Nordic Semiconductor ASA

 *

 * SPDX-License-Identifier: Apache-2.0

 */

#include <stdio.h>

#include <zephyr.h>

#include <device.h>

#include <drivers/gpio.h>

#include <drivers/sensor.h>

static void fetch_and_display(struct device *sensor)

{

	static unsigned int count;

	struct sensor_value mag;

	int rc = sensor_sample_fetch(sensor);

	++count;

	if (rc == 0) {

		rc = sensor_channel_get(sensor,

					SENSOR_CHAN_PROX,

					&mag);

	}

	if (rc < 0) {

		printf("ERROR: Update failed: %d\n", rc);

	} else {

		printf("#%u @ %u ms: %d\n",

		       count, k_uptime_get_32(), mag.val1);

	}

}

#ifdef CONFIG_SM351LT_TRIGGER

static void trigger_handler(struct device *dev,

			    struct sensor_trigger *trig)

{

	fetch_and_display(dev);

}

#endif

void main(void)

{

	struct device *sensor = device_get_binding(DT_LABEL(DT_INST(0, honeywell_sm351lt)));

	if (sensor == NULL) {

		printf("Could not get %s device\n",

		       DT_LABEL(DT_INST(0, honeywell_sm351lt)));

		return;

	}

#if CONFIG_SM351LT_TRIGGER

	{

		struct sensor_trigger trig;

		int rc;

		trig.type = SENSOR_TRIG_NEAR_FAR;

		trig.chan = SENSOR_CHAN_PROX;

		struct sensor_value trigger_type = {

			.val1 = GPIO_INT_EDGE_BOTH,

		};

		rc = sensor_attr_set(sensor, trig.chan,

				     SENSOR_ATTR_PRIV_START,

				     &trigger_type);

		if (rc != 0) {

			printf("Failed to set trigger type: %d\n", rc);

			return;

		}

		rc = sensor_trigger_set(sensor, &trig, trigger_handler);

		if (rc != 0) {

			printf("Failed to set trigger: %d\n", rc);

			return;

		}

		printf("Waiting for triggers\n");

		while (true) {

			k_sleep(K_MSEC(2000));

		}

	}

#else /* CONFIG_SM351LT_TRIGGER */

	printf("Polling at 0.5 Hz\n");

	while (true) {

		fetch_and_display(sensor);

		k_sleep(K_MSEC(2000));

	}

#endif /* CONFIG_SM351LT_TRIGGER */

}