samples: sensor: Add simple quadrature decoder demo

Add simple application to demonstrate quadrature decoder sensor.

Tested on Atmel SMART SAM E70 Xplained board.

Signed-off-by: Piotr Mienkowski <[email protected]>

Author: mnkp

samples/sensor/qdec/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(thermometer)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/sensor/qdec/README.rst

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+.. _qdec:
+
+QDEC: Quadrature Decoder
+###########################
+
+Overview
+********
+A simple quadrature decoder example
+
+Building and Running
+********************
+
+This project writes the quadrature decoder position to the console once every
+2 seconds.
+
+Building on SAM E70 Xplained board
+==================================
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/sensor/qdec
+   :host-os: unix
+   :board: sam_e70_xplained
+   :goals: build
+   :compact:
+
+Sample Output
+=============
+
+.. code-block:: console
+
+    Quadrature Decoder sample application
+
+    Position is 6
+    Position is 12
+    Position is -45
+
+    <repeats endlessly every 2 seconds>

samples/sensor/qdec/boards/sam_e70_xplained.conf

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+CONFIG_QDEC_SAM=y

samples/sensor/qdec/boards/sam_e70_xplained.overlay

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+/*
+ * Copyright (c) 2021, Piotr Mienkowski
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&tc0 {
+	status = "okay";
+	pinctrl-0 = <&pa0b_tc0_tioa0 &pa1b_tc0_tiob0>;
+	label = "QDEC_0";
+};

samples/sensor/qdec/prj.conf

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+CONFIG_SENSOR=y
+CONFIG_STDOUT_CONSOLE=y

samples/sensor/qdec/sample.yaml

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+sample:
+  name: Quadrature Decoder
+tests:
+  sample.sensor.qdec:
+    tags: sensors
+    harness: sensor
+    platform_allow: sam_e70_xplained

samples/sensor/qdec/src/main.c

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+/*
+ * Copyright (c) 2021, Piotr Mienkowski
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr.h>
+#include <drivers/sensor.h>
+#include <stdio.h>
+
+void main(void)
+{
+	const struct device *dev;
+	int ret;
+
+	printf("Quadrature Decoder sample application\n\n");
+
+	dev = device_get_binding("QDEC_0");
+	if (!dev) {
+		printf("error: no QDEC_0 device\n");
+		return;
+	}
+
+	while (1) {
+		struct sensor_value value;
+
+		ret = sensor_sample_fetch(dev);
+		if (ret) {
+			printf("sensor_sample_fetch failed returns: %d\n", ret);
+			break;
+		}
+
+		ret = sensor_channel_get(dev, SENSOR_CHAN_ROTATION, &value);
+		if (ret) {
+			printf("sensor_channel_get failed returns: %d\n", ret);
+			break;
+		}
+
+		printf("Position is %d\n", value.val1);
+
+		k_sleep(K_MSEC(2000));
+	}
+}