ChipPinSelectManager.cpp

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/*
 * This file is part of the DUDS project. It is subject to the BSD-style
 * license terms in the LICENSE file found in the top-level directory of this
 * distribution and at https://github.com/jjackowski/duds/blob/master/LICENSE.
 * No part of DUDS, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 *
 * Copyright (C) 2017  Jeff Jackowski
 */
#include <duds/hardware/interface/ChipPinSelectManager.hpp>
#include <duds/hardware/interface/ChipSelectErrors.hpp>

namespace duds { namespace hardware { namespace interface {

bool ChipPinSelectManager::validChip(int chipId) const noexcept {
    return selpin && (chipId == 1);
}

void ChipPinSelectManager::select() {
    selpin->output(selstate);
}

void ChipPinSelectManager::deselect() {
    selpin->output(!selstate);
}

void ChipPinSelectManager::setSelectPin(
    std::unique_ptr<DigitalPinAccess> &&dpa,
    SelectState selectState
) {
    if (!dpa || !dpa->havePin()) {
        DUDS_THROW_EXCEPTION(PinDoesNotExist());
    }
    // require exclusive access
    std::unique_lock<std::mutex> lock(block);
    // is a chip in use?
    if (inUse()) {
        assert(selpin);
        // fail; provide the pin and chip IDs for what is currently in use
        DUDS_THROW_EXCEPTION(ChipSelectInUse() <<
            PinErrorId(selpin->globalId()) << ChipSelectIdError(1)
        );
    }
    // get the capabilities for inspection
    DigitalPinCap cap = dpa->capabilities();
    // check for no output ability
    if (!cap.canOutput()) {
        DUDS_THROW_EXCEPTION(DigitalPinCannotInputError() <<
            PinErrorId(dpa->globalId())
        );
    }
    // assure a deselected state prior to requesting output
    dpa->output(!selectState);
    // work out the actual output config
    dpa->modifyConfig(DigitalPinConfig(cap.firstOutputDriveConfigFlags()));
    // store this access object; seems good if it got this far without
    // an exception
    selpin = std::move(dpa);
    selstate = selectState;
}

ChipPinSelectManager::ChipPinSelectManager(
    std::unique_ptr<DigitalPinAccess> &&dpa,
    SelectState selectState
) {
    setSelectPin(std::move(dpa), selectState);
}

ChipPinSelectManager::~ChipPinSelectManager() {
    shutdown();
}

} } }