/**************************************************************************** * drivers/sensors/mpl115a.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you 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. * ****************************************************************************/ /* Character driver for the Freescale MPL115A1 Barometer Sensor */ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_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 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 = { NULL, /* open */ NULL, /* close */ mpl115a_read, /* read */ mpl115a_write, /* write */ }; /**************************************************************************** * Private Functions ****************************************************************************/ 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_HWFEATURES(spi, 0); SPI_SETFREQUENCY(spi, MPL115A_SPI_MAXFREQUENCY); } /**************************************************************************** * 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 */ SPI_LOCK(priv->spi, true); mpl115a_configspi(priv->spi); /* Select the MPL115A */ SPI_SELECT(priv->spi, SPIDEV_BAROMETER(0), true); /* Send register to read and get the next byte */ SPI_SEND(priv->spi, regaddr); SPI_RECVBLOCK(priv->spi, ®val, 1); /* Deselect the MPL115A */ SPI_SELECT(priv->spi, SPIDEV_BAROMETER(0), false); /* Unlock bus */ SPI_LOCK(priv->spi, false); #ifdef CONFIG_MPL115A_REGDEBUG _err("%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)); sninfo("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)); sninfo("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)); sninfo("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)); sninfo("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 */ nxsig_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 */ sninfo("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 */ sninfo("Temperature = %d\n", priv->mpl115a_temperature); /* Feed sensor data to entropy pool */ add_sensor_randomness((priv->mpl115a_pressure << 16) ^ 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; int32_t a1; int32_t a1x1; int32_t y1; int32_t a2x2; int32_t pcomp; uint16_t padc; uint16_t tadc; uint16_t 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. */ sninfo("Final Pressure = %d\n", pressure >> 4); return pressure; } /**************************************************************************** * 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) { snerr("ERROR: Buffer is null\n"); return -1; } if (buflen != 2) { snerr("ERROR:"); snerr(" 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) { snerr("ERROR: 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) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } return ret; } #endif /* CONFIG_SPI && CONFIG_SENSORS_MPL115A */