File content as of revision 13:0645d8841f51:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 *
 * 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.h"

#if DEVICE_I2C

namespace mbed {

I2C *I2C::_owner = NULL;

I2C::I2C(PinName sda, PinName scl) {
    // The init function also set the frequency to 100000
    i2c_init(&_i2c, sda, scl);
    _hz = 100000;

    // Used to avoid unnecessary frequency updates
    _owner = this;
}

void I2C::frequency(int hz) {
    _hz = hz;

    // We want to update the frequency even if we are already the bus owners
    i2c_frequency(&_i2c, _hz);

    // Updating the frequency of the bus we become the owners of it
    _owner = this;
}

void I2C::aquire() {
    if (_owner != this) {
        i2c_frequency(&_i2c, _hz);
        _owner = this;
    }
}

// write - Master Transmitter Mode
int I2C::write(int address, const char* data, int length, bool repeated) {
    aquire();

    int stop = (repeated) ? 0 : 1;
    int written = i2c_write(&_i2c, address, data, length, stop);

    return length != written;
}

int I2C::write(int data) {
    return i2c_byte_write(&_i2c, data);
}

// read - Master Reciever Mode
int I2C::read(int address, char* data, int length, bool repeated) {
    aquire();

    int stop = (repeated) ? 0 : 1;
    int read = i2c_read(&_i2c, address, data, length, stop);

    return length != read;
}

int I2C::read(int ack) {
    if (ack) {
        return i2c_byte_read(&_i2c, 0);
    } else {
        return i2c_byte_read(&_i2c, 1);
    }
}

void I2C::start(void) {
    i2c_start(&_i2c);
}

void I2C::stop(void) {
    i2c_stop(&_i2c);
}

} // namespace mbed

#endif