drivers: regulator: add set callback API and driver for Nordic USB VBUS regulator

include/zephyr/drivers/regulator.h

@@ -63,6 +63,33 @@ typedef uint8_t regulator_error_flags_t;
 
 /** @} */
 
+/**
+ * @brief Regulator event types
+ */
+enum regulator_event_type {
+	/** @brief Regulator voltage is detected */
+	REGULATOR_VOLTAGE_DETECTED,
+	/** @brief Regulator voltage is removed */
+	REGULATOR_VOLTAGE_REMOVED,
+};
+
+/** @brief Regulator event structure */
+struct regulator_event {
+	enum regulator_event_type type;
+};
+
+/**
+ * @typedef regulator_callback_t
+ * @brief Regulator callback function signature
+ *
+ * @param dev Regulator device instance
+ * @param evt Regulator event
+ * @param user_data User data
+ */
+typedef void (*regulator_callback_t)(const struct device *dev,
+				     const struct regulator_event *const evt,
+				     const void *const user_data);
+
 /** @cond INTERNAL_HIDDEN */
 
 typedef int (*regulator_dvs_state_set_t)(const struct device *dev,
@@ -102,6 +129,8 @@ typedef int (*regulator_get_active_discharge_t)(const struct device *dev,
 				    bool *active_discharge);
 typedef int (*regulator_get_error_flags_t)(
 	const struct device *dev, regulator_error_flags_t *flags);
+typedef int (*regulator_set_callback_t)(const struct device *dev,
+	regulator_callback_t cb, const void *const user_data);
 
 /** @brief Driver-specific API functions to support regulator control. */
 __subsystem struct regulator_driver_api {
@@ -120,6 +149,7 @@ __subsystem struct regulator_driver_api {
 	regulator_set_active_discharge_t set_active_discharge;
 	regulator_get_active_discharge_t get_active_discharge;
 	regulator_get_error_flags_t get_error_flags;
+	regulator_set_callback_t set_callback;
 };
 
 /**
@@ -765,6 +795,34 @@ static inline int regulator_get_error_flags(const struct device *dev,
 	return api->get_error_flags(dev, flags);
 }
 
+/**
+ * @brief Set event handler function.
+ *
+ * The regulator may generate an interrupt when, for example, the voltage is
+ * present. This can be used for USB VBUS voltage regulators to notify that a
+ * device is connected to a port.
+ *
+ * @param dev Regulator device instance
+ * @param cb Event handler
+ * @param user_data User data
+ *
+ * @retval 0 If successful.
+ * @retval -ENOSYS If not supported by the device.
+ */
+static inline int regulator_set_callback(const struct device *dev,
+					 regulator_callback_t cb,
+					 const void *const user_data)
+{
+	const struct regulator_driver_api *api =
+		(const struct regulator_driver_api *)dev->api;
+
+	if (api->set_callback == NULL) {
+		return -ENOSYS;
+	}
+
+	return api->set_callback(dev, cb, user_data);
+}
+
 #ifdef __cplusplus
 }
 #endif