/**************************************************************************** * drivers/sensors/bmp180.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 BMP1801 Barometer Sensor */ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_BMP180) /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define BMP180_ADDR 0x77 #define BMP180_FREQ 100000 #define DEVID 0x55 #define BMP180_AC1_MSB 0xaa #define BMP180_AC1_LSB 0xab #define BMP180_AC2_MSB 0xac #define BMP180_AC2_LSB 0xad #define BMP180_AC3_MSB 0xae #define BMP180_AC3_LSB 0xaf #define BMP180_AC4_MSB 0xb0 #define BMP180_AC4_LSB 0xb1 #define BMP180_AC5_MSB 0xb2 #define BMP180_AC5_LSB 0xb3 #define BMP180_AC6_MSB 0xb4 #define BMP180_AC6_LSB 0xb5 #define BMP180_B1_MSB 0xb6 #define BMP180_B1_LSB 0xb7 #define BMP180_B2_MSB 0xb8 #define BMP180_B2_LSB 0xb9 #define BMP180_MB_MSB 0xba #define BMP180_MB_LSB 0xbb #define BMP180_MC_MSB 0xbc #define BMP180_MC_LSB 0xbd #define BMP180_MD_MSB 0xbe #define BMP180_MD_LSB 0xbf #define BMP180_DEVID 0xd0 #define BMP180_SOFT_RESET 0xe0 #define BMP180_CTRL_MEAS 0xf4 #define BMP180_ADC_OUT_MSB 0xf6 #define BMP180_ADC_OUT_LSB 0xf7 #define BMP180_ADC_OUT_XLSB 0xf8 #define BMP180_READ_TEMP 0x2e #define BMP180_READ_PRESS 0x34 #define BMP180_NOOVERSAMPLE 0x00 #define BMP180_OVERSAMPLE2X 0x70 #define BMP180_OVERSAMPLE4X 0xb0 #define BMP180_OVERSAMPLE8X 0xc0 /* Current Oversampling */ #define CURRENT_OSS (BMP180_OVERSAMPLE8X) /**************************************************************************** * Private Type Definitions ****************************************************************************/ struct bmp180_dev_s { FAR struct i2c_master_s *i2c; /* I2C interface */ uint8_t addr; /* BMP180 I2C address */ int freq; /* BMP180 Frequency <= 3.4MHz */ int16_t bmp180_cal_ac1; /* Calibration coefficients */ int16_t bmp180_cal_ac2; int16_t bmp180_cal_ac3; uint16_t bmp180_cal_ac4; uint16_t bmp180_cal_ac5; uint16_t bmp180_cal_ac6; int16_t bmp180_cal_b1; int16_t bmp180_cal_b2; int16_t bmp180_cal_mb; int16_t bmp180_cal_mc; int16_t bmp180_cal_md; int32_t bmp180_utemp; /* Uncompensated temperature read from BMP180 */ int32_t bmp180_upress; /* Uncompensated pressure read from BMP180 */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static uint8_t bmp180_getreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr); static uint16_t bmp180_getreg16(FAR struct bmp180_dev_s *priv, uint8_t regaddr); static void bmp180_putreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr, uint8_t regval); static void bmp180_updatecaldata(FAR struct bmp180_dev_s *priv); static void bmp180_read_press_temp(FAR struct bmp180_dev_s *priv); static int bmp180_getpressure(FAR struct bmp180_dev_s *priv); /* Character driver methods */ static ssize_t bmp180_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t bmp180_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_bmp180fops = { NULL, /* open */ NULL, /* close */ bmp180_read, /* read */ bmp180_write, /* write */ NULL, /* seek */ NULL, /* ioctl */ NULL /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: bmp180_getreg8 * * Description: * Read from an 8-bit BMP180 register * ****************************************************************************/ static uint8_t bmp180_getreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr) { struct i2c_config_s config; uint8_t regval = 0; int ret; /* Set up the I2C configuration */ config.frequency = priv->freq; config.address = priv->addr; config.addrlen = 7; /* Write the register address */ ret = i2c_write(priv->i2c, &config, ®addr, 1); if (ret < 0) { snerr("ERROR: i2c_write failed: %d\n", ret); return ret; } /* Read the register value */ ret = i2c_read(priv->i2c, &config, ®val, 1); if (ret < 0) { snerr("ERROR: i2c_read failed: %d\n", ret); return ret; } return regval; } /**************************************************************************** * Name: bmp180_getreg16 * * Description: * Read two 8-bit from a BMP180 register * ****************************************************************************/ static uint16_t bmp180_getreg16(FAR struct bmp180_dev_s *priv, uint8_t regaddr) { struct i2c_config_s config; uint16_t msb; uint16_t lsb; uint16_t regval = 0; int ret; /* Set up the I2C configuration */ config.frequency = priv->freq; config.address = priv->addr; config.addrlen = 7; /* Register to read */ ret = i2c_write(priv->i2c, &config, ®addr, 1); if (ret < 0) { snerr("ERROR: i2c_write failed: %d\n", ret); return ret; } /* Read register */ ret = i2c_read(priv->i2c, &config, (uint8_t *)®val, 2); if (ret < 0) { snerr("ERROR: i2c_read failed: %d\n", ret); return ret; } /* MSB and LSB are inverted */ msb = (regval & 0xff); lsb = (regval & 0xff00) >> 8; regval = (msb << 8) | lsb; return regval; } /**************************************************************************** * Name: bmp180_putreg8 * * Description: * Write to an 8-bit BMP180 register * ****************************************************************************/ static void bmp180_putreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr, uint8_t regval) { struct i2c_config_s config; uint8_t data[2]; int ret; /* Set up the I2C configuration */ config.frequency = priv->freq; config.address = priv->addr; config.addrlen = 7; data[0] = regaddr; data[1] = regval; /* Write the register address and value */ ret = i2c_write(priv->i2c, &config, (uint8_t *) &data, 2); if (ret < 0) { snerr("ERROR: i2c_write failed: %d\n", ret); return; } } /**************************************************************************** * Name: bmp180_checkid * * Description: * Read and verify the BMP180 chip ID * ****************************************************************************/ static int bmp180_checkid(FAR struct bmp180_dev_s *priv) { uint8_t devid = 0; /* Read device ID */ devid = bmp180_getreg8(priv, BMP180_DEVID); sninfo("devid: 0x%02x\n", devid); if (devid != (uint16_t)DEVID) { /* ID is not Correct */ snerr("ERROR: Wrong Device ID!\n"); return -ENODEV; } return OK; } /**************************************************************************** * Name: bmp180_updatecaldata * * Description: * Update Calibration Coefficient Data * ****************************************************************************/ static void bmp180_updatecaldata(FAR struct bmp180_dev_s *priv) { /* AC1 */ priv->bmp180_cal_ac1 = (int16_t) bmp180_getreg16(priv, BMP180_AC1_MSB); /* AC2 */ priv->bmp180_cal_ac2 = (int16_t) bmp180_getreg16(priv, BMP180_AC2_MSB); /* AC3 */ priv->bmp180_cal_ac3 = (int16_t) bmp180_getreg16(priv, BMP180_AC3_MSB); /* AC4 */ priv->bmp180_cal_ac4 = bmp180_getreg16(priv, BMP180_AC4_MSB); /* AC5 */ priv->bmp180_cal_ac5 = bmp180_getreg16(priv, BMP180_AC5_MSB); /* AC6 */ priv->bmp180_cal_ac6 = bmp180_getreg16(priv, BMP180_AC6_MSB); /* B1 */ priv->bmp180_cal_b1 = (int16_t) bmp180_getreg16(priv, BMP180_B1_MSB); /* B2 */ priv->bmp180_cal_b2 = (int16_t) bmp180_getreg16(priv, BMP180_B2_MSB); /* MB */ priv->bmp180_cal_mb = (int16_t) bmp180_getreg16(priv, BMP180_MB_MSB); /* MC */ priv->bmp180_cal_mc = (int16_t) bmp180_getreg16(priv, BMP180_MC_MSB); /* MD */ priv->bmp180_cal_md = (int16_t) bmp180_getreg16(priv, BMP180_MD_MSB); } /**************************************************************************** * Name: bmp180_read_press_temp * * Description: * Read raw pressure and temperature from BMP180 and store it in the * bmp180_dev_s structure. * ****************************************************************************/ static void bmp180_read_press_temp(FAR struct bmp180_dev_s *priv) { uint8_t oss = CURRENT_OSS; /* Issue a read temperature command */ bmp180_putreg8(priv, BMP180_CTRL_MEAS, BMP180_READ_TEMP); /* Wait 5ms */ nxsig_usleep(5000); /* Read temperature */ priv->bmp180_utemp = bmp180_getreg16(priv, BMP180_ADC_OUT_MSB); /* Issue a read pressure command */ bmp180_putreg8(priv, BMP180_CTRL_MEAS, (BMP180_READ_PRESS | oss)); /* Delay 25.5ms (to OverSampling 8X) */ nxsig_usleep(25500); /* Read pressure */ priv->bmp180_upress = bmp180_getreg16(priv, BMP180_ADC_OUT_MSB) << 8; priv->bmp180_upress |= bmp180_getreg8(priv, BMP180_ADC_OUT_XLSB); priv->bmp180_upress = priv->bmp180_upress >> (8 - (oss >> 6)); sninfo("Uncompensated temperature = %" PRId32 "\n", priv->bmp180_utemp); sninfo("Uncompensated pressure = %" PRId32 "\n", priv->bmp180_upress); } /**************************************************************************** * Name: bmp180_getpressure * * Description: * Calculate the Barometric Pressure using the temperature compensated * See Freescale AN3785 and BMP1801 data sheet for details * ****************************************************************************/ static int bmp180_getpressure(FAR struct bmp180_dev_s *priv) { int32_t x1; int32_t x2; int32_t x3; int32_t b3; int32_t b5; int32_t b6; int32_t press; int32_t temp; uint32_t b4; uint32_t b7; uint8_t oss = (CURRENT_OSS >> 6); /* Check if coefficient data were read correctly */ if ((priv->bmp180_cal_ac1 == 0) || (priv->bmp180_cal_ac2 == 0) || (priv->bmp180_cal_ac3 == 0) || (priv->bmp180_cal_ac4 == 0) || (priv->bmp180_cal_ac5 == 0) || (priv->bmp180_cal_ac6 == 0) || (priv->bmp180_cal_b1 == 0) || (priv->bmp180_cal_b2 == 0) || (priv->bmp180_cal_mb == 0) || (priv->bmp180_cal_mc == 0) || (priv->bmp180_cal_md == 0)) { bmp180_updatecaldata(priv); } /* Read temperature and pressure */ bmp180_read_press_temp(priv); /* Feed raw sensor data to entropy pool */ add_sensor_randomness((priv->bmp180_utemp << 16) ^ priv->bmp180_upress); /* Calculate true temperature */ x1 = ((priv->bmp180_utemp - priv->bmp180_cal_ac6) * priv->bmp180_cal_ac5) >> 15; x2 = (priv->bmp180_cal_mc << 11) / (x1 + priv->bmp180_cal_md); b5 = x1 + x2; temp = (b5 + 8) >> 4; sninfo("Compensated temperature = %" PRId32 "\n", temp); UNUSED(temp); /* Calculate true pressure */ b6 = b5 - 4000; x1 = (priv->bmp180_cal_b2 * ((b6 * b6) >> 12)) >> 11; x2 = (priv->bmp180_cal_ac2 * b6) >> 11; x3 = x1 + x2; b3 = (((((int32_t) priv->bmp180_cal_ac1) * 4 + x3) << oss) + 2) >> 2; x1 = (priv->bmp180_cal_ac3 * b6) >> 13; x2 = (priv->bmp180_cal_b1 * ((b6 * b6) >> 12)) >> 16; x3 = ((x1 + x2) + 2) >> 2; b4 = (priv->bmp180_cal_ac4 * (uint32_t) (x3 + 32768)) >> 15; b7 = ((uint32_t) (priv->bmp180_upress - b3) * (50000 >> oss)); if (b7 < 0x80000000) { press = (b7 << 1) / b4; } else { press = (b7 / b4) << 1; } x1 = (press >> 8) * (press >> 8); x1 = (x1 * 3038) >> 16; x2 = (-7357 * press) >> 16; press = press + ((x1 + x2 + 3791) >> 4); sninfo("Compressed pressure = %" PRId32 "\n", press); return press; } /**************************************************************************** * Name: bmp180_read ****************************************************************************/ static ssize_t bmp180_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct bmp180_dev_s *priv = inode->i_private; FAR uint32_t *press = (FAR uint32_t *) buffer; if (!buffer) { snerr("ERROR: Buffer is null\n"); return -1; } if (buflen != 4) { snerr("ERROR: You can't read something " "other than 32 bits (4 bytes)\n"); return -1; } /* Get the pressure compensated */ *press = (int32_t) bmp180_getpressure(priv); /* Return size of uint32_t (4 bytes) */ return 4; } /**************************************************************************** * Name: bmp180_write ****************************************************************************/ static ssize_t bmp180_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: bmp180_register * * Description: * Register the BMP180 character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/press0" * i2c - An instance of the I2C interface to use to communicate with * BMP180 * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int bmp180_register(FAR const char *devpath, FAR struct i2c_master_s *i2c) { FAR struct bmp180_dev_s *priv; int ret; /* Initialize the BMP180 device structure */ priv = (FAR struct bmp180_dev_s *)kmm_malloc(sizeof(struct bmp180_dev_s)); if (!priv) { snerr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->i2c = i2c; priv->addr = BMP180_ADDR; priv->freq = BMP180_FREQ; /* Check Device ID */ ret = bmp180_checkid(priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); return ret; } /* Read the coefficient value */ bmp180_updatecaldata(priv); /* Register the character driver */ ret = register_driver(devpath, &g_bmp180fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } sninfo("BMP180 driver loaded successfully!\n"); return ret; } #endif /* CONFIG_I2C && CONFIG_SENSORS_BMP180 */