samples: sensor: stts22h: Minimal polling sample

Add a simple STTS22H sample that utilizes the Zephyr sensor API
in polling mode to fetch and print the ambient temperature every
2 seconds periodically.

Signed-off-by: Charles Dias <[email protected]>

Author: CharlesDias

samples/sensor/stts22h/CMakeLists.txt

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+# Copyright (c) 2025 Charles Dias
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(stts22h)
+
+target_sources(app PRIVATE src/main.c)

samples/sensor/stts22h/README.rst

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+.. zephyr:code-sample:: stts22h
+   :name: STTS22H Temperature sensor
+   :relevant-api: sensor_interface
+
+  Get ambient temperature from the STTS22H sensor.
+
+Overview
+********
+
+This sample reads the onboard STTS22H ambient temperature sensor using the Zephyr
+sensor API and prints the value periodically to the console.
+
+Requirements
+************
+
+This sample uses the STTS22H sensor controlled using the I2C interface.
+
+References
+**********
+
+ - STTS22H: https://www.st.com/en/mems-and-sensors/stts22h.html
+
+Building and Running
+********************
+
+This project outputs STTS22H temperature data to the console. It requires a
+board that has an STTS22H connected over I2C and enabled in its devicetree.
+
+Examples of supported boards include STM32U5G9J-DK1, where the sensor is
+enabled at I2C3 address 0x3F in the board DTS.
+
+.. zephyr-app-commands::
+    :zephyr-app: samples/sensor/stts22h/
+    :board: stm32u5g9j_dk1
+    :goals: build flash
+
+
+Sample Output
+=============
+
+.. code-block:: console
+  Zephyr STTS22H sensor sample. Board: stm32u5g9j_dk1
+  [    10 ms] Temperature: 27.7 C
+  [  2013 ms] Temperature: 27.6 C
+  [  4016 ms] Temperature: 27.6 C
+  [  6019 ms] Temperature: 27.6 C
+
+  <repeats endlessly every 2 seconds>

samples/sensor/stts22h/prj.conf

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+CONFIG_STDOUT_CONSOLE=y
+CONFIG_I2C=y
+CONFIG_GPIO=y
+CONFIG_SENSOR=y
+
+CONFIG_STTS22H_TRIGGER_NONE=y
+
+#debug
+#CONFIG_DEBUG=y
+#CONFIG_LOG=y
+#CONFIG_SENSOR_LOG_LEVEL_DBG=y
+
+CONFIG_CBPRINTF_FP_SUPPORT=y

samples/sensor/stts22h/sample.yaml

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+sample:
+  name: STTS22H temperature sensor
+tests:
+  sample.sensor.stts22h:
+    depends_on:
+      - i2c
+    filter: dt_compat_enabled("st,stts22h")
+    tags:
+      - sensors
+    integration_platforms:
+      - stm32u5g9j_dk1
+    harness: console
+    harness_config:
+      type: multi_line
+      regex:
+        - "Temperature: (.*)"

samples/sensor/stts22h/src/main.c

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+/*
+ * Copyright (c) 2025 Charles Dias
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/printk.h>
+
+#include <zephyr/drivers/sensor.h>
+
+#include <stdio.h>
+
+static void stts22h_config(const struct device *stts22h)
+{
+	struct sensor_value odr_attr;
+
+	/* Set STTS22H ODR to 100 Hz (or as close as supported) */
+	odr_attr.val1 = 100;
+	odr_attr.val2 = 0;
+	if (sensor_attr_set(stts22h, SENSOR_CHAN_AMBIENT_TEMP,
+			    SENSOR_ATTR_SAMPLING_FREQUENCY, &odr_attr) < 0) {
+		printk("Cannot set sampling frequency for STTS22H\n");
+		return;
+	}
+}
+
+int main(void)
+{
+	const struct device *const stts22h = DEVICE_DT_GET_ONE(st_stts22h);
+	int ret;
+
+	printf("Zephyr STTS22H sensor sample. Board: %s\n", CONFIG_BOARD);
+
+	if (!device_is_ready(stts22h)) {
+		printk("%s: device not ready.\n", stts22h->name);
+		return 0;
+	}
+
+	stts22h_config(stts22h);
+
+	while (1) {
+		struct sensor_value temp;
+
+		ret = sensor_sample_fetch(stts22h);
+		if (ret < 0) {
+			printk("STTS22H sample fetch error (%d)\n", ret);
+			k_msleep(1000);
+			continue;
+		}
+
+		ret = sensor_channel_get(stts22h, SENSOR_CHAN_AMBIENT_TEMP, &temp);
+		if (ret < 0) {
+			printk("STTS22H channel read error (%d)\n", ret);
+			k_msleep(1000);
+			continue;
+		}
+
+		printf("[%6lld ms] Temperature: %.1f C\n", k_uptime_get(),
+			sensor_value_to_double(&temp));
+
+		k_msleep(2000);
+	}
+}