phosphor-regulators/src/actions/i2c_write_bytes_action.cpp

/**
 * Copyright © 2020 IBM Corporation
 *
 * 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.
 */

#include "i2c_write_bytes_action.hpp"

#include "action_error.hpp"
#include "i2c_interface.hpp"

#include <exception>
#include <ios>
#include <sstream>

namespace phosphor::power::regulators
{

bool I2CWriteBytesAction::execute(ActionEnvironment& environment)
{
    try
    {
        i2c::I2CInterface& interface = getI2CInterface(environment);
        uint8_t valuesToWrite[UINT8_MAX];
        if (masks.size() == 0)
        {
            for (unsigned int i = 0; i < values.size(); ++i)
            {
                valuesToWrite[i] = values[i];
            }
        }
        else
        {
            // Read current device register values.  Use I2C mode where the
            // number of bytes to read is explicitly specified.
            uint8_t size = values.size();
            uint8_t currentValues[UINT8_MAX];
            interface.read(reg, size, currentValues,
                           i2c::I2CInterface::Mode::I2C);

            // Combine values to write with current values
            for (unsigned int i = 0; i < values.size(); ++i)
            {
                valuesToWrite[i] = (values[i] & masks[i]) |
                                   (currentValues[i] & (~masks[i]));
            }
        }

        // Write values to device register
        interface.write(reg, values.size(), valuesToWrite,
                        i2c::I2CInterface::Mode::I2C);
    }
    catch (const i2c::I2CException& e)
    {
        // Nest I2CException within an ActionError so caller will have both the
        // low level I2C error information and the action information
        std::throw_with_nested(ActionError(*this));
    }
    return true;
}

std::string I2CWriteBytesAction::toString() const
{
    std::ostringstream ss;
    ss << "i2c_write_bytes: { register: 0x" << std::hex << std::uppercase
       << static_cast<uint16_t>(reg) << ", values: [ ";
    for (unsigned int i = 0; i < values.size(); ++i)
    {
        ss << ((i > 0) ? ", " : "") << "0x" << static_cast<uint16_t>(values[i]);
    }
    ss << " ], masks: [ ";
    for (unsigned int i = 0; i < masks.size(); ++i)
    {
        ss << ((i > 0) ? ", " : "") << "0x" << static_cast<uint16_t>(masks[i]);
    }
    ss << " ] }";
    return ss.str();
}

} // namespace phosphor::power::regulators