/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2016 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include <upm_utilities.h>

#include "mb704x.h"

// The delay to wait (in ms) for a ranging command to complete before
// requesting the range data.
#define MB704X_RANGE_DELAY     (100)

// range command
#define MB704X_CMD_RANGE       (81)

mb704x_context mb704x_init(unsigned int bus, int addr)
{
    // make sure MRAA is initialized
    int mraa_rv;
    if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
    {
        printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
        return NULL;
    }

    mb704x_context dev =
        (mb704x_context)malloc(sizeof(struct _mb704x_context));

    if (!dev)
        return NULL;

    // zero out context
    memset((void *)dev, 0, sizeof(struct _mb704x_context));

    // initialize the MRAA contexts

    if (!(dev->i2c = mraa_i2c_init(bus)))
    {
        printf("%s: mraa_i2c_init() failed.\n", __FUNCTION__);
        mb704x_close(dev);
        return NULL;
    }

    if (mraa_i2c_address(dev->i2c, (uint8_t)addr))
    {
        printf("%s: mraa_i2c_address() failed.\n", __FUNCTION__);
        mb704x_close(dev);
        return NULL;
    }

    // max power up delay
    upm_delay_ms(135);

    return dev;
}

void mb704x_close(mb704x_context dev)
{
    assert(dev != NULL);

    if (dev->i2c)
        mraa_i2c_stop(dev->i2c);

    free(dev);
}

int mb704x_get_range(const mb704x_context dev)
{
    assert(dev != NULL);

    // first, send the range command.
    uint8_t cmd = MB704X_CMD_RANGE;
    if (mraa_i2c_write(dev->i2c, &cmd, 1))
    {
        printf("%s: mraa_i2c_write() failed.\n", __FUNCTION__);
        return -1;
    }

    // delay for measurement
    upm_delay_ms(MB704X_RANGE_DELAY);

    // At this point, we should be able to do our read of the data
    uint8_t buffer[2];
    if (mraa_i2c_read(dev->i2c, buffer, 2) != 2)
    {
        printf("%s: mraa_i2c_read() failed.\n", __FUNCTION__);
        return -1;
    }

    return ((buffer[0] << 8) | buffer[1]);
}