Files
upm/src/mb704x/mb704x.c
2016-12-02 16:44:43 -07:00

116 lines
3.1 KiB
C

/*
* 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]);
}