tv/tuner/1.0/IFrontend.hal

/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package android.hardware.tv.tuner@1.0;

import IFrontendCallback;

/**
 * A Tuner Frontend is used to tune to a frequency and lock signal. It provide
 * live data feed to Tuner Demux interface.
 */
interface IFrontend {
    /**
     * Set the callback
     *
     * It is used by the client to receive events from the Frontend.
     * Only one callback for one Frontend instance is supported. The callback
     * will be replaced if it's set again.
     *
     * @param callback Callback object to pass Frontend events to the system.
     *        The previously registered callback must be replaced with this one.
     *        It can be null.
     * @return result Result status of the operation.
     *         SUCCESS if successful,
     *         INVALID_STATE if callback can't be set at current stage,
     *         UNKNOWN_ERROR if callback setting failed for other reasons.
     */
    setCallback(IFrontendCallback callback) generates (Result result);

    /**
     * Tuning Frontend
     *
     * It is used by the client to lock a frequency by providing signal
     * delivery information. If previous tuning isn't completed, this call must
     * stop previous tuning, and start a new tuning. Tune is a async call.
     * LOCKED or NO_SIGNAL eventi is sent back to caller through callback.
     *
     * @param settings Signal delivery information which frontend can use to
     * search and lock the signal.
     *
     * @return result Result status of the operation.
     *         SUCCESS if successful,
     *         INVALID_STATE if tuning can't be applied at current stage,
     *         UNKNOWN_ERROR if tuning failed for other reasons.
     */
    tune(FrontendSettings settings) generates (Result result);

    /**
     * Stop the tuning
     *
     * It is used by the client to stop a previous tuning.
     *
     * @return result Result status of the operation.
     *         SUCCESS if successfully stop tuning.
     *         UNKNOWN_ERROR if failed for other reasons.
     */
    stopTune() generates (Result result);

    /**
     * Release the Frontend instance
     *
     * It is used by the client to release the frontend instance. HAL clear
     * underneath resource. client mustn't access the instance any more.
     *
     * @return result Result status of the operation.
     *         SUCCESS if successful,
     *         UNKNOWN_ERROR if failed for other reasons.
     */
    close() generates (Result result);
};