/****************************************************************************
* drivers/sensors/mpl115a.c
* Character driver for the Freescale MPL115A1 Barometer Sensor
*
* Copyright (C) 2015 Gregory Nutt. All rights reserved.
* Copyright (C) 2015 Alan Carvalho de Assis
* Author: Alan Carvalho de Assis <acassis@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <fixedmath.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/spi/spi.h>
#include <nuttx/sensors/mpl115a.h>
#if defined(CONFIG_SPI) && defined(CONFIG_MPL115A)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private
****************************************************************************/
struct mpl115a_dev_s
{
FAR struct spi_dev_s *spi; /* SPI interface */
int16_t mpl115a_cal_a0;
int16_t mpl115a_cal_b1;
int16_t mpl115a_cal_b2;
int16_t mpl115a_cal_c12;
uint16_t mpl115a_temperature;
uint16_t mpl115a_pressure;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static inline void mpl115a_configspi(FAR struct spi_dev_s *spi);
static uint8_t mpl115a_getreg8(FAR struct mpl115a_dev_s *priv, uint8_t regaddr);
static void mpl115a_updatecaldata(FAR struct mpl115a_dev_s *priv);
static void mpl115a_read_press_temp(FAR struct mpl115a_dev_s *priv);
static int mpl115a_getpressure(FAR struct mpl115a_dev_s *priv);
/* Character driver methods */
static int mpl115a_open(FAR struct file *filep);
static int mpl115a_close(FAR struct file *filep);
static ssize_t mpl115a_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t mpl115a_write(FAR struct file *filep, FAR const char *buffer, size_t buflen);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mpl115afops =
{
mpl115a_open, /* open */
mpl115a_close, /* close */
mpl115a_read, /* read */
mpl115a_write, /* write */
0, /* seek */
0, /* ioctl */
#ifndef CONFIG_DISABLE_POLL
0, /* poll */
#endif
0 /* unlink */
};
/****************************************************************************
* Private Functions
****************************************************************************/
#ifndef CONFIG_SPI_OWNBUS
static inline void mpl115a_configspi(FAR struct spi_dev_s *spi)
{
/* Configure SPI for the MPL115A */
SPI_SETMODE(spi, SPIDEV_MODE0);
SPI_SETBITS(spi, 8);
SPI_SETFREQUENCY(spi, MPL115A_SPI_MAXFREQUENCY);
}
#endif
/****************************************************************************
* Name: mpl115a_getreg8
*
* Description:
* Read from an 8-bit MPL115A register
*
****************************************************************************/
static uint8_t mpl115a_getreg8(FAR struct mpl115a_dev_s *priv, uint8_t regaddr)
{
uint8_t regval;
/* If SPI bus is shared then lock and configure it */
#ifndef CONFIG_SPI_OWNBUS
(void)SPI_LOCK(priv->spi, true);
mpl115a_configspi(priv->spi);
#endif
/* Select the MPL115A */
SPI_SELECT(priv->spi, SPIDEV_BAROMETER, true);
/* Send register to read and get the next byte */
(void)SPI_SEND(priv->spi, regaddr);
SPI_RECVBLOCK(priv->spi, ®val, 1);
/* Deselect the MPL115A */
SPI_SELECT(priv->spi, SPIDEV_BAROMETER, false);
/* Unlock bus */
#ifndef CONFIG_SPI_OWNBUS
(void)SPI_LOCK(priv->spi, false);
#endif
#ifdef CONFIG_MPL115A_REGDEBUG
dbg("%02x->%02x\n", regaddr, regval);
#endif
return regval;
}
/****************************************************************************
* Name: mpl115a_updatecaldata
*
* Description:
* Update Calibration Coefficient Data
*
****************************************************************************/
static void mpl115a_updatecaldata(FAR struct mpl115a_dev_s *priv)
{
/* Get a0 coefficient */
priv->mpl115a_cal_a0 = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_A0_MSB << 1)) << 8;
priv->mpl115a_cal_a0 |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_A0_LSB << 1));
sndbg("a0 = %d\n", priv->mpl115a_cal_a0);
/* Get b1 coefficient */
priv->mpl115a_cal_b1 = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_B1_MSB << 1)) << 8;
priv->mpl115a_cal_b1 |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_B1_LSB << 1));
sndbg("b1 = %d\n", priv->mpl115a_cal_b1);
/* Get b2 coefficient */
priv->mpl115a_cal_b2 = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_B2_MSB << 1)) << 8;
priv->mpl115a_cal_b2 |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_B2_LSB << 1));
sndbg("b2 = %d\n", priv->mpl115a_cal_b2);
/* Get c12 coefficient */
priv->mpl115a_cal_c12 = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_C12_MSB << 1)) << 8;
priv->mpl115a_cal_c12 |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_C12_LSB << 1));
sndbg("c12 = %d\n", priv->mpl115a_cal_c12);
}
/****************************************************************************
* Name: mpl115a_read_press_temp
*
* Description:
* Read raw pressure and temperature from MPL115A and store it in the
* mpl115a_dev_s structure.
*
****************************************************************************/
static void mpl115a_read_press_temp(FAR struct mpl115a_dev_s *priv)
{
/* Start a new conversion */
mpl115a_getreg8(priv, (MPL115A_CONVERT << 1));
/* Delay 5ms */
usleep(5000);
priv->mpl115a_pressure = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_PADC_MSB << 1)) << 8;
priv->mpl115a_pressure |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_PADC_LSB << 1));
priv->mpl115a_pressure >>= 6; /* Padc is 10bit unsigned */
sndbg("Pressure = %d\n", priv->mpl115a_pressure);
priv->mpl115a_temperature = mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_TADC_MSB << 1)) << 8;
priv->mpl115a_temperature |= mpl115a_getreg8(priv, MPL115A_BASE_CMD | (MPL115A_TADC_LSB << 1));
priv->mpl115a_temperature >>= 6; /* Tadc is 10bit unsigned */
sndbg("Temperature = %d\n", priv->mpl115a_temperature);
}
/****************************************************************************
* Name: mpl115a_getpressure
*
* Description:
* Calculate the Barometric Pressure using the temperature compensated
* See Freescale AN3785 and MPL115A1 data sheet for details
*
****************************************************************************/
static int mpl115a_getpressure(FAR struct mpl115a_dev_s *priv)
{
int32_t c12x2, a1, a1x1, y1, a2x2, pcomp;
uint16_t padc, tadc, pressure;
/* Check if coefficient data were read correctly */
if ((priv->mpl115a_cal_a0 == 0) || (priv->mpl115a_cal_b1 == 0) ||
(priv->mpl115a_cal_b2 == 0) || (priv->mpl115a_cal_c12 == 0))
{
mpl115a_updatecaldata(priv);
}
/* Read temperature and pressure */
mpl115a_read_press_temp(priv);
padc = priv->mpl115a_pressure;
tadc = priv->mpl115a_temperature;
/* These code are from Freescale AN3785 */
c12x2 = ((int32_t)priv->mpl115a_cal_c12 * tadc) >> 11;
a1 = (int32_t) (priv->mpl115a_cal_b1 + c12x2);
a1x1 = a1 * padc;
y1 = (((int32_t)priv->mpl115a_cal_a0) << 10) + a1x1;
a2x2 = (((int32_t)priv->mpl115a_cal_b2) * tadc) >> 1;
pcomp = (y1 + a2x2) >> 9;
/* Calculate the pressure in 1/16 kPa from compensated */
pressure = (((((int32_t)pcomp) * 1041) >> 14) + 800);
/* Note that the final pressure value is reported with 4 bit fractional
* This may be eliminated by right shifting the result 4 bits.
*/
sndbg("Final Pressure = %d\n", pressure >> 4);
return pressure;
}
/****************************************************************************
* Name: mpl115a_open
*
* Description:
* This function is called whenever the MPL115A1 device is opened.
*
****************************************************************************/
static int mpl115a_open(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: mpl115a_close
*
* Description:
* This routine is called when the LM-75 device is closed.
*
****************************************************************************/
static int mpl115a_close(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: mpl115a_read
****************************************************************************/
static ssize_t mpl115a_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpl115a_dev_s *priv = inode->i_private;
FAR uint16_t *press = (FAR uint16_t *) buffer;
if (!buffer)
{
sndbg("Buffer is null\n");
return -1;
}
if (buflen != 2)
{
sndbg("You can't read something other than 16 bits (2 bytes)\n");
return -1;
}
/* Get the pressure compensated */
*press = mpl115a_getpressure(priv);
/* Return size of uint16_t (2 bytes) */
return 2;
}
/****************************************************************************
* Name: mpl115a_write
****************************************************************************/
static ssize_t mpl115a_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mpl115a_register
*
* Description:
* Register the MPL115A character device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/temp0"
* i2c - An instance of the I2C interface to use to communicate with
* MPL115A
* addr - The I2C address of the LM-75. The base I2C address of the
* MPL115A is 0x48. Bits 0-3 can be controlled to get 8 unique
* addresses from 0x48 through 0x4f.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mpl115a_register(FAR const char *devpath, FAR struct spi_dev_s *spi)
{
FAR struct mpl115a_dev_s *priv;
int ret;
/* Initialize the MPL115A device structure */
priv = (FAR struct mpl115a_dev_s *)kmm_malloc(sizeof(struct mpl115a_dev_s));
if (!priv)
{
sndbg("Failed to allocate instance\n");
return -ENOMEM;
}
priv->spi = spi;
priv->mpl115a_cal_a0 = 0;
priv->mpl115a_cal_b1 = 0;
priv->mpl115a_cal_b2 = 0;
priv->mpl115a_cal_c12 = 0;
/* Read the coefficient value */
mpl115a_updatecaldata(priv);
/* Register the character driver */
ret = register_driver(devpath, &g_mpl115afops, 0666, priv);
if (ret < 0)
{
sndbg("Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_SPI && CONFIG_MPL115A */