ChipBinarySelectManager.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/ChipBinarySelectManager.hpp>
#include <duds/hardware/interface/ChipSelectErrors.hpp>

namespace duds { namespace hardware { namespace interface {

bool ChipBinarySelectManager::validChip(int chipId) const noexcept {
    return selpin && (chipId >= 0) && (chipId <= 1);
}

void ChipBinarySelectManager::select() {
    selpin->output(cid > 0);
}

void ChipBinarySelectManager::deselect() {
    selpin->output(cid == 0);
}

void ChipBinarySelectManager::setSelectPin(
    std::unique_ptr<DigitalPinAccess> &&dpa,
    int initSel
) {
    if (!dpa) {
        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(DigitalPinCannotOutputError() <<
            PinErrorId(dpa->globalId())
        );
    }
    // assure the requested state prior to begining output
    dpa->output(initSel > 0);
    // work out the actual output config
    if (cap & DigitalPinCap::OutputPushPull) {
        dpa->modifyConfig(DigitalPinConfig(
            DigitalPinConfig::DirOutput | DigitalPinConfig::OutputPushPull
        ));
    } else if (cap & DigitalPinCap::OutputDriveLow) {
        dpa->modifyConfig(DigitalPinConfig(
            DigitalPinConfig::DirOutput | DigitalPinConfig::OutputDriveLow
        ));
    } else {
        dpa->modifyConfig(DigitalPinConfig(
            DigitalPinConfig::DirOutput | DigitalPinConfig::OutputDriveHigh
        ));
    }
    // store this access object; seems good if it got this far without
    // an exception
    selpin = std::move(dpa);
}

ChipBinarySelectManager::ChipBinarySelectManager() { }

ChipBinarySelectManager::ChipBinarySelectManager(
    std::unique_ptr<DigitalPinAccess> &&dpa, int initSel
) {
    setSelectPin(std::move(dpa), initSel);
}

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

} } }