samples: sensor: Add CPU temperature monitor sample

Add a polling sample for CPU temperature monitor.
This sample demonstrates how to data fetch and print to the console.

Signed-off-by: TOKITA Hiroshi <[email protected]>

Author: soburi

samples/sensor/die_temp_polling/CMakeLists.txt

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+# Copyright (c) 2023 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(die_temp_polling)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/sensor/die_temp_polling/README.rst

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+.. _die_temp_polling:
+
+CPU Die Temperature polling
+###########################
+
+Overview
+********
+
+This sample periodically reads temperature from the CPU Die
+temperature sensor and display the results.
+
+Building and Running
+********************
+
+To run this sample, enable the sensor node that supports ``SENSOR_CHAN_DIE_TEMP``
+and create an alias named ``die-temp0`` to link to the node.
+The tail ``0`` is the sensor number.  This sample support up to 15 sensors.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/sensor/die_temp_polling
+   :board: rpi_pico
+   :goals: build
+   :compact:
+
+Sample Output
+=============
+
+.. code-block:: console
+
+    CPU Die temperature[dietemp]: 22.6 °C
+    CPU Die temperature[dietemp]: 22.8 °C
+    CPU Die temperature[dietemp]: 23.1 °C

samples/sensor/die_temp_polling/boards/rpi_pico.conf

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+CONFIG_ADC=y

samples/sensor/die_temp_polling/boards/rpi_pico.overlay

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2023 TOKITA Hiroshi
+ */
+
+&die_temp {
+	status = "okay";
+};

samples/sensor/die_temp_polling/prj.conf

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+CONFIG_SENSOR=y
+CONFIG_ADC=y
+CONFIG_PRINTK=y
+CONFIG_CBPRINTF_FP_SUPPORT=y

samples/sensor/die_temp_polling/sample.yaml

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+sample:
+  description: CPU Die temperature polling sample
+  name: die_temp_polling
+tests:
+  sample.sensor.die_temperature_polling:
+    tags: sensors tests
+    filter: dt_alias_exists("die-temp0")
+    harness: console
+    harness_config:
+      type: one_line
+      regex:
+        - "CPU Die temperature\\[[A-Za-z0-9_]+\\]: [1-9][0-9].[0-9] °C"

samples/sensor/die_temp_polling/src/main.c

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+/*
+ * Copyright (c) 2023 TOKITA Hiroshi
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/sys/printk.h>
+
+#define DIE_TEMP_ALIAS(i) DT_ALIAS(_CONCAT(die_temp, i))
+#define DIE_TEMPERATURE_SENSOR(i, _)                                                               \
+	IF_ENABLED(DT_NODE_EXISTS(DIE_TEMP_ALIAS(i)), (DEVICE_DT_GET(DIE_TEMP_ALIAS(i)),))
+
+/* support up to 16 cpu die temperature sensors */
+static const struct device *const sensors[] = {LISTIFY(16, DIE_TEMPERATURE_SENSOR, ())};
+
+static int print_die_temperature(const struct device *dev)
+{
+	struct sensor_value val;
+	int rc;
+
+	/* fetch sensor samples */
+	rc = sensor_sample_fetch(dev);
+	if (rc) {
+		printk("Failed to fetch sample (%d)\n", rc);
+		return rc;
+	}
+
+	rc = sensor_channel_get(dev, SENSOR_CHAN_DIE_TEMP, &val);
+	if (rc) {
+		printk("Failed to get data (%d)\n", rc);
+		return rc;
+	}
+
+	printk("CPU Die temperature[%s]: %.1f °C\n", dev->name, sensor_value_to_double(&val));
+	return 0;
+}
+
+void main(void)
+{
+	int rc;
+
+	for (size_t i = 0; i < ARRAY_SIZE(sensors); i++) {
+		if (!device_is_ready(sensors[i])) {
+			printk("sensor: device %s not ready.\n", sensors[i]->name);
+			return;
+		}
+	}
+
+	while (1) {
+		for (size_t i = 0; i < ARRAY_SIZE(sensors); i++) {
+			rc = print_die_temperature(sensors[i]);
+			if (rc < 0) {
+				return;
+			}
+		}
+		k_msleep(300);
+	}
+}