feat(adc_test): use devicetree for adc configuration

- Use named adc channel 'multisense' from devicetree
- Enable adc calibration

software/apps/adc_test/boards/weact_stm32g431_core.overlay

@@ -0,0 +1,31 @@
+/ {
+    zephyr,user {
+        io-channels = <&adc1 1>;
+        io-channel-names = "multisense";
+    };
+};
+
+&adc1 {
+    #address-cells = <1>;
+    #size-cells = <0>;
+    status = "okay";
+    st,adc-clock-source = "SYNC";
+    st,adc-prescaler = <4>;
+    pinctrl-0 = <&adc1_in1_pa0>;
+    pinctrl-names = "default";
+
+    channel@1 {
+        reg = <1>;
+        zephyr,gain = "ADC_GAIN_1";
+        zephyr,reference = "ADC_REF_INTERNAL";
+        zephyr,acquisition-time = <ADC_ACQ_TIME_MAX>;
+        zephyr,resolution = <12>;
+        zephyr,vref-mv = <3300>;
+    };
+};
+
+&pinctrl {
+    adc1_in1_pa0: adc1_in1_pa0 {
+        pinmux = <STM32_PINMUX('A', 0, ANALOG)>;
+    };
+};

software/apps/adc_test/prj.conf

@@ -0,0 +1,3 @@
+CONFIG_ADC=y
+CONFIG_ADC_STM32=y
+CONFIG_LOG=y

software/apps/adc_test/src/main.c

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2024 Your Name
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/adc.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(adc_test, LOG_LEVEL_DBG);
+
+#if !DT_NODE_EXISTS(DT_PATH(zephyr_user))
+#error "zephyr,user node not found"
+#endif
+
+static const struct adc_dt_spec adc_channel = ADC_DT_SPEC_GET_BY_NAME(DT_PATH(zephyr_user), multisense);
+
+int main(void)
+{
+	int err;
+
+	if (!device_is_ready(adc_channel.dev)) {
+		LOG_ERR("ADC device not found: %s", adc_channel.dev->name);
+		return 0;
+	}
+
+	err = adc_channel_setup_dt(&adc_channel);
+	if (err < 0) {
+		LOG_ERR("Could not setup channel #%d, error %d", adc_channel.channel_id, err);
+		return 0;
+	}
+
+	while (1) {
+		int16_t buffer[1];
+		struct adc_sequence sequence = {
+			.channels    = BIT(adc_channel.channel_id),
+			.buffer      = buffer,
+			.buffer_size = sizeof(buffer),
+			.resolution  = adc_channel.resolution,
+            .calibrate = true,
+		};
+
+		err = adc_read(adc_channel.dev, &sequence);
+		if (err < 0) {
+			LOG_ERR("Could not read ADC, error %d", err);
+			continue;
+		}
+
+		int32_t millivolts = buffer[0];
+		err = adc_raw_to_millivolts_dt(&adc_channel, &millivolts);
+		if (err < 0) {
+			LOG_ERR("Could not convert to millivolts (%d)", err);
+			continue;
+		}
+
+		LOG_INF("ADC raw: %d, mV: %d", buffer[0], millivolts);
+
+		k_msleep(500);
+	}
+	return 0;
+}