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/**
* @file ms5611_i2c.cpp
*
* I2C interface for MS5611
*/
/* XXX trim includes */
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <debug.h>
#include <errno.h>
#include <unistd.h>
#include <arch/board/board.h>
#include <drivers/device/i2c.h>
#include "ms5611.h"
#include "board_config.h"
#define MS5611_ADDRESS_1 0x76 /* address select pins pulled high (PX4FMU series v1.6+) */
#define MS5611_ADDRESS_2 0x77 /* address select pins pulled low (PX4FMU prototypes) */
device::Device *MS5611_i2c_interface(ms5611::prom_u &prom_buf);
class MS5611_I2C : public device::I2C
{
public:
MS5611_I2C(uint8_t bus, ms5611::prom_u &prom_buf);
virtual ~MS5611_I2C();
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();
};
device::Device *
MS5611_i2c_interface(ms5611::prom_u &prom_buf, uint8_t busnum)
{
return new MS5611_I2C(busnum, prom_buf);
}
MS5611_I2C::MS5611_I2C(uint8_t bus, ms5611::prom_u &prom) :
I2C("MS5611_I2C", nullptr, bus, 0, 400000),
_prom(prom)
{
}
MS5611_I2C::~MS5611_I2C()
{
}
int
MS5611_I2C::init()
{
/* this will call probe(), and thereby _probe_address */
return I2C::init();
}
int
MS5611_I2C::read(unsigned offset, void *data, unsigned count)
{
union _cvt {
uint8_t b[4];
uint32_t w;
} *cvt = (_cvt *)data;
uint8_t buf[3];
/* read the most recent measurement */
uint8_t cmd = 0;
int ret = transfer(&cmd, 1, &buf[0], 3);
if (ret == OK) {
/* fetch the raw value */
cvt->b[0] = buf[2];
cvt->b[1] = buf[1];
cvt->b[2] = buf[0];
cvt->b[3] = 0;
}
return ret;
}
int
MS5611_I2C::ioctl(unsigned operation, unsigned &arg)
{
int ret;
switch (operation) {
case IOCTL_RESET:
ret = _reset();
break;
case IOCTL_MEASURE:
ret = _measure(arg);
break;
default:
ret = EINVAL;
}
return ret;
}
int
MS5611_I2C::probe()
{
_retries = 10;
if ((OK == _probe_address(MS5611_ADDRESS_1)) ||
(OK == _probe_address(MS5611_ADDRESS_2))) {
/*
* Disable retries; we may enable them selectively in some cases,
* but the device gets confused if we retry some of the commands.
*/
_retries = 0;
return OK;
}
return -EIO;
}
int
MS5611_I2C::_probe_address(uint8_t address)
{
/* select the address we are going to try */
set_address(address);
/* send reset command */
if (OK != _reset())
return -EIO;
/* read PROM */
if (OK != _read_prom())
return -EIO;
return OK;
}
int
MS5611_I2C::_reset()
{
unsigned old_retrycount = _retries;
uint8_t cmd = ADDR_RESET_CMD;
int result;
/* bump the retry count */
_retries = 10;
result = transfer(&cmd, 1, nullptr, 0);
_retries = old_retrycount;
return result;
}
int
MS5611_I2C::_measure(unsigned addr)
{
/*
* Disable retries on this command; we can't know whether failure
* means the device did or did not see the command.
*/
_retries = 0;
uint8_t cmd = addr;
return transfer(&cmd, 1, nullptr, 0);
}
int
MS5611_I2C::_read_prom()
{
uint8_t prom_buf[2];
union {
uint8_t b[2];
uint16_t w;
} cvt;
/*
* 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);
if (OK != transfer(&cmd, 1, &prom_buf[0], 2))
break;
/* assemble 16 bit value and convert from big endian (sensor) to little endian (MCU) */
cvt.b[0] = prom_buf[1];
cvt.b[1] = prom_buf[0];
_prom.c[i] = cvt.w;
}
/* calculate CRC and return success/failure accordingly */
return ms5611::crc4(&_prom.c[0]) ? OK : -EIO;
}
