diff options
Diffstat (limited to 'src/drivers/ms5611/ms5611_spi.cpp')
| -rw-r--r-- | src/drivers/ms5611/ms5611_spi.cpp | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/src/drivers/ms5611/ms5611_spi.cpp b/src/drivers/ms5611/ms5611_spi.cpp new file mode 100644 index 000000000..eed8e1697 --- /dev/null +++ b/src/drivers/ms5611/ms5611_spi.cpp @@ -0,0 +1,228 @@ +/**************************************************************************** + * + * Copyright (c) 2013 PX4 Development Team. All rights reserved. + * + * 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 PX4 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. + * + ****************************************************************************/ + + /** + * @file ms5611_spi.cpp + * + * SPI interface for MS5611 + */ + + +/* SPI protocol address bits */ +#define DIR_READ (1<<7) +#define DIR_WRITE (0<<7) +#define ADDR_INCREMENT (1<<6) + +device::Device *MS5611_spi_interface(); + +class MS5611_SPI : device::SPI +{ +public: + MS5611_SPI(int bus, spi_dev_e device); + virtual ~MS5611_SPI(); + + virtual int init(); + virtual int read(unsigned offset, void *data, unsigned count); + virtual int ioctl(unsigned operation, unsigned &arg); + +protected: + virtual int probe(); + +private: + ms5611::prom_u *_prom + + int _probe_address(uint8_t address); + + /** + * Send a reset command to the MS5611. + * + * This is required after any bus reset. + */ + int _reset(); + + /** + * Send a measure command to the MS5611. + * + * @param addr Which address to use for the measure operation. + */ + int _measure(unsigned addr); + + /** + * Read the MS5611 PROM + * + * @return OK if the PROM reads successfully. + */ + int _read_prom(); + + /** + * Read a 16-bit register value. + * + * @param reg The register to read. + */ + uint16_t _reg16(unsigned reg); +}; + +device::Device * +MS5611_spi_interface() +{ +#ifdef PX4_SPIDEV_BARO + return new MS5611_SPI(1 /* XXX MAGIC NUMBER */, (spi_dev_e)PX4_SPIDEV_BARO); +#endif + return nullptr; +} + +int +MS5611_SPI::init() +{ + int ret; + + ret = SPI::init(); + if (ret != OK) + goto out; + + /* send reset command */ + ret = _reset(); + if (ret != OK) + goto out; + + /* read PROM */ + ret = _read_prom(); + if (ret != OK) + goto out; + +out: + return ret; +} + +int +MS5611_SPI::read(unsigned offset, void *data, unsigned count) +{ + union _cvt { + uint8_t b[4]; + uint32_t w; + } *cvt = (_cvt *)data; + uint8_t buf[4]; + + /* read the most recent measurement */ + buf[0] = 0 | DIR_WRITE; + int ret = transfer(&buf[0], &buf[0], sizeof(buf)); + + if (ret == OK) { + /* fetch the raw value */ + cvt->b[0] = data[3]; + cvt->b[1] = data[2]; + cvt->b[2] = data[1]; + cvt->b[3] = 0; + + ret = count; + } + + return ret; +} + +int +MS5611_SPI::ioctl(unsigned operation, unsigned &arg) +{ + int ret; + + switch (operation) { + case IOCTL_SET_PROMBUFFER: + _prom = reinterpret_cast<ms5611_prom_u *>(arg); + return OK; + + case IOCTL_RESET: + ret = _reset(); + break; + + case IOCTL_MEASURE: + ret = _measure(arg); + break; + + default: + ret = EINVAL; + } + + if (ret != OK) { + errno = ret; + return -1; + } + return 0; +} + +int +MS5611_SPI::_reset() +{ + uint8_t cmd = ADDR_RESET_CMD | DIR_WRITE; + + return transfer(&cmd, nullptr, 1); +} + +int +MS5611_SPI::_measure(unsigned addr) +{ + uint8_t cmd = addr | DIR_WRITE; + + return transfer(&cmd, nullptr, 1); +} + + +int +MS5611_SPI::_read_prom() +{ + /* + * Wait for PROM contents to be in the device (2.8 ms) in the case we are + * called immediately after reset. + */ + usleep(3000); + + /* read and convert PROM words */ + for (int i = 0; i < 8; i++) { + uint8_t cmd = (ADDR_PROM_SETUP + (i * 2)); + _prom.c[i] = _reg16(cmd); + } + + /* calculate CRC and return success/failure accordingly */ + return ms5611::crc4(&_prom.c[0]) ? OK : -EIO; +} + +uint16_t +MS5611_SPI::_reg16(unsigned reg) +{ + uint8_t cmd[3]; + + cmd[0] = reg | DIR_READ; + + transfer(cmd, cmd, sizeof(cmd)); + + return (uint16_t)(cmd[1] << 8) | cmd[2]; +} |