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