Battery measurement, basic version

firmware/libs/batt_mgmt/include/batt_mgmt.h

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+#ifndef BATT_MGMT_H
+#define BATT_MGMT_H
+
+#include <zephyr/types.h>
+#include <stdbool.h>
+
+#define BATT_MGMT_OVERSAMPLING_8X 8U
+#define BATT_MGMT_OVERSAMPLING_16X 16U
+
+typedef enum {
+	BATT_STATE_DISCHARGING = 0,
+	BATT_STATE_FULL,
+	BATT_STATE_CHARGING,
+	BATT_STATE_ERROR,
+	BATT_STATE_UNKNOWN,
+} batt_mgmt_state_t;
+
+/**
+ * @brief Measure battery VDDH voltage.
+ *
+ * @param oversampling Oversampling factor (BATT_MGMT_OVERSAMPLING_8X or BATT_MGMT_OVERSAMPLING_16X).
+ * @param vddh_mv Pointer to store the result in millivolts.
+ * @return 0 on success, negative errno on failure.
+ */
+int batt_mgmt_measure_vddh_mv(uint8_t oversampling, int32_t *vddh_mv);
+
+/**
+ * @brief Get raw charger status (GPIO level).
+ *
+ * Returns the current logic level of the charger status pin (typically from ETA6003).
+ * This is the **raw GPIO status**, not a processed state machine result.
+ *
+ * @return true if charger pin is high (e.g., battery is "full"), false if low.
+ */
+bool batt_mgmt_get_charger_status(void);
+
+/**
+ * @brief Get processed battery state with blinking detection.
+ *
+ * Returns a derived state based on:
+ * - USB VBUS presence (from usb_mgmt)
+ * - Charger status GPIO level (from batt_mgmt_get_charger_status)
+ * - Blinking detection (state changes within CONFIG_BATT_MGMT_CHG_BLINKING_WINDOW_MS)
+ *
+ * Note: This differs from batt_mgmt_get_charger_status() which returns the **raw** GPIO level.
+ *
+ * @return Battery state enum (DISCHARGING, FULL, CHARGING, or ERROR if blinking detected).
+ */
+batt_mgmt_state_t batt_mgmt_get_battery_state(void);
+
+#endif
+