sample: sensor: add gecko acmp sample

- Add sample for Gecko ACMP sensor driver

Signed-off-by: Romain Pelletant <[email protected]>

samples/sensor/gecko_acmp/CMakeLists.txt

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

samples/sensor/gecko_acmp/README.rst

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+.. zephyr:code-sample:: gecko_acmp
+   :name: SiLabs Gecko Analog Comparator (ACMP)
+   :relevant-api: sensor_interface
+
+   Get analog comparator data from an SiLabs Gecko Analog Comparator (ACMP).
+
+Overview
+********
+
+This sample show how to use the SiLabs Gecko Analog Comparator (ACMP) driver.
+
+In this application, the negative input port of the ACMP is muxed to the internal
+low-power reference voltage 1.25V.
+The positive input port is muxed to VDD (VSENSE01DIV4LP) divided by 4.
+The threshold value is set to 20h (32d).
+Corresponding voltage threshold VREFOUT = VREFIN * (VREFDIV / 63) = (1.25V * 4) * (32 / 63) = 2.54V.
+The ACMP output shall be set to 1 when VDD voltage is under 2.54V and is reported on the console.
+
+Building and Running
+********************
+
+Building and Running for SiLabs EFR32MG24 Mighty Gecko Board dev kit
+=========================================
+Build the application for the :zephyr:board:`xg24_dk2601b` board, and adjust the
+ACMP positive/negative input ports and vrefdiv in xg24_dk2601b.overlay file directly.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/sensor/gecko_acmp
+   :board: xg24_dk2601b
+   :goals: build flash
+   :compact:

samples/sensor/gecko_acmp/boards/xg24_dk2601b.overlay

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+/*
+ * Copyright 2025 Kickmaker
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&acmp0 {
+	status = "okay";
+	bias-level = <0>;
+	input-range = "Reduced";
+	accuracy = "Low";
+	vrefdiv = <0x20>;
+	hysteresis-level = "Disabled";
+	positive-input = "VSENSE01DIV4LP";
+	negative-input = "VREFDIV1V25LP";
+	interrupt-mode = "FallingEdge";
+};

samples/sensor/gecko_acmp/prj.conf

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+CONFIG_SENSOR=y
+CONFIG_GECKO_ACMP_TRIGGER=y

samples/sensor/gecko_acmp/sample.yaml

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+sample:
+  description: Demonstration of the SiLabs Gecko ACMP driver
+  name: SiLabs Gecko ACMP sample
+common:
+  platform_allow:
+    - xg24_dk2601b
+  integration_platforms:
+    - xg24_dk2601b
+  tags:
+    - drivers
+    - sensor
+tests:
+  sample.sensor.gecko_acmp:
+    harness: console
+    harness_config:
+      type: one_line
+      ordered: true
+      regex:
+        - "ACMP input [a-z]* threshold"
+  sample.sensor.gecko_acmp.no_trigger:
+    build_only: true
+    extra_configs:
+      - CONFIG_GECKO_ACMP_TRIGGER=n

samples/sensor/gecko_acmp/src/main.c

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+/*
+ * Copyright Kickmaker 2025
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/sensor/gecko_acmp.h>
+#include <zephyr/kernel.h>
+#include <stdio.h>
+
+#ifdef CONFIG_GECKO_ACMP_TRIGGER
+static const int16_t triggers[] = {
+	SENSOR_TRIG_GECKO_ACMP_OUTPUT_RISING,
+	SENSOR_TRIG_GECKO_ACMP_OUTPUT_FALLING,
+};
+#endif /* CONFIG_GECKO_ACMP_TRIGGER */
+
+static void acmp_input_handler(bool above_threshold)
+{
+	if (above_threshold) {
+		printf("ACMP input above threshold\n");
+	} else {
+		printf("ACMP input below threshold\n");
+	}
+}
+
+#ifdef CONFIG_GECKO_ACMP_EDGE_COUNTER
+static void acmp_read_edge_counters(const struct device *dev, struct sensor_value *val)
+{
+	int err;
+
+	if (!val) {
+		return;
+	}
+
+	err = sensor_sample_fetch(dev);
+	if (err) {
+		printf("failed to fetch sample (err %d)\n", err);
+		return;
+	}
+
+	err = sensor_channel_get(dev, SENSOR_CHAN_GECKO_ACMP_RISING_EDGE_COUNTER, val);
+	if (err) {
+		printf("failed to get channel (err %d)\n", err);
+		return;
+	}
+
+	printf("Rising edge counter: %d\n", val.val1);
+
+	err = sensor_channel_get(dev, SENSOR_CHAN_GECKO_ACMP_FALLING_EDGE_COUNTER, &val);
+	if (err) {
+		printf("failed to get channel (err %d)\n", err);
+		return;
+	}
+
+	printf("Falling edge counter: %d\n", val.val1);
+}
+#endif /* CONFIG_GECKO_ACMP_EDGE_COUNTER */
+
+#ifdef CONFIG_GECKO_ACMP_TRIGGER
+static void acmp_trigger_handler(const struct device *dev, const struct sensor_trigger *trigger)
+{
+	ARG_UNUSED(dev);
+
+	acmp_input_handler((int16_t)trigger->type == SENSOR_TRIG_GECKO_ACMP_OUTPUT_RISING);
+}
+#endif /* CONFIG_GECKO_ACMP_TRIGGER */
+
+int main(void)
+{
+#ifdef CONFIG_GECKO_ACMP_TRIGGER
+	struct sensor_trigger trigger[ARRAY_SIZE(triggers)] = {
+		[0] = {
+				.chan = SENSOR_CHAN_GECKO_ACMP_OUTPUT,
+				.type = triggers[0],
+			},
+		[1] = {
+				.chan = SENSOR_CHAN_GECKO_ACMP_OUTPUT,
+				.type = triggers[1],
+			}
+		};
+#endif /* CONFIG_GECKO_ACMP_TRIGGER */
+	const struct device *const acmp = DEVICE_DT_GET(DT_NODELABEL(acmp0));
+	int err;
+
+	if (!device_is_ready(acmp)) {
+		printf("ACMP device not ready\n");
+		return 0;
+	}
+
+#ifdef CONFIG_GECKO_ACMP_TRIGGER
+	/* Set ACMP triggers */
+	for (uint8_t i = 0; i < ARRAY_SIZE(triggers); i++) {
+		err = sensor_trigger_set(acmp, &trigger[i], acmp_trigger_handler);
+		if (err) {
+			printf("failed to set trigger %d (err %d)\n", i, err);
+			return 0;
+		}
+	}
+
+	/* Await trigger */
+	while (true) {
+#ifdef CONFIG_GECKO_ACMP_EDGE_COUNTER
+		struct sensor_value val;
+
+		acmp_read_edge_counters(acmp, &val);
+#endif /* CONFIG_GECKO_ACMP_EDGE_COUNTER */
+		k_sleep(K_SECONDS(1));
+	}
+#else  /* !CONFIG_GECKO_ACMP_TRIGGER */
+	while (true) {
+		struct sensor_value val;
+
+		err = sensor_sample_fetch(acmp);
+		if (err) {
+			printf("failed to fetch sample (err %d)\n", err);
+			return 0;
+		}
+
+		err = sensor_channel_get(acmp, SENSOR_CHAN_GECKO_ACMP_OUTPUT, &val);
+		if (err) {
+			printf("failed to get channel (err %d)\n", err);
+			return 0;
+		}
+
+		acmp_input_handler(val.val1 == 1);
+
+		k_sleep(K_MSEC(1));
+	}
+
+#endif /* CONFIG_GECKO_ACMP_TRIGGER */
+
+	return 0;
+}