laelaps::LaeI2C Class Reference

#include <laeI2C.h>

Public Member Functions
	LaeI2C ()
	Default constructor.
virtual	~LaeI2C ()
	Destructor.
virtual int	open (const std::string &strDevName)
	Open I2C bus device. More...
virtual int	close ()
	Close I2C bus device. More...
virtual bool	check (uint_t addr)
	Check if an I2C slave endpoint exists. More...
virtual int	read (uint_t addr, byte_t buf[], size_t len)
	Read from a I2C slave endpoint device. More...
virtual int	write (uint_t addr, const byte_t buf[], size_t len)
	Write to an I2C slave endpoint device. More...
virtual int	transfer (uint_t addr, const byte_t wbuf[], size_t wlen, byte_t rbuf[], size_t rlen)
	Perform a write/read transfer to/from an I2C slave endpoint device. More...
virtual int	write_read (uint_t addr, const byte_t wbuf[], size_t wlen, byte_t rbuf[], size_t rlen, long usec=0)
	Perform a write/read transaction to/from an I2C slave endpoint device. More...
std::string	getDevName ()
	Get associated I2C device name. More...
bool	isOpen ()
	Check if device is open. More...

Protected Member Functions
void	lock ()
	Lock the I2C bus. More...
void	unlock ()
	Unlock the I2C bus. More...

Protected Attributes
std::string	m_strDevName
	I2C device name.
i2c_t	m_i2c
	I2C bus instance.
pthread_mutex_t	m_mutex
	mutual exclusion

Detailed Description

I2C class.

Definition at line 76 of file laeI2C.h.

Member Function Documentation

bool LaeI2C::check ( uint_t  addr )

virtual

Check if an I²C slave endpoint exists.

Parameters

addr	Endpoint I2C device's 7/10-bit address.

Returns

Returns true or false.

Definition at line 162 of file laeI2C.cxx.

References m_i2c.

Referenced by laelaps::i2cTryOpen().

{
  return i2c_exists(&m_i2c, (i2c_addr_t)addr) == 1;
}

int LaeI2C::close ( )

virtual

Close I²C bus device.

Returns

On success, OK(0) is returned.
On error, RC_ERROR(-1) is returned.

Definition at line 144 of file laeI2C.cxx.

References I2CBusNone, laelaps::LAE_OK, lock(), m_i2c, m_strDevName, and unlock().

Referenced by Laelaps.WatchDog.WatchDog::attach(), laelaps::LaeRobot::disconnect(), laelaps::i2cTryOpen(), main(), Laelaps.WatchDog.WatchDog::open(), and ~LaeI2C().

{
  lock();

  if( m_i2c.fd >= 0 )
  {
    i2c_close(&m_i2c);
    LOGDIAG3("I2C device %s closed.", m_strDevName.c_str());
  }

  m_strDevName.clear();
  m_i2c = I2CBusNone;

  unlock();

  return LAE_OK;
}

std::string laelaps::LaeI2C::getDevName ( )

inline

Get associated I²C device name.

Returns

Returns device name string. Empty if no device.

Definition at line 193 of file laeI2C.h.

References m_strDevName.

Referenced by laelaps::LaeI2CMux::getDevName().

    {
      return m_strDevName;
    }

bool laelaps::LaeI2C::isOpen ( )

inline

Check if device is open.

Returns

Returns true or false.

Definition at line 203 of file laeI2C.h.

References m_i2c.

Referenced by Laelaps.WatchDog.WatchDog::cmdConfigDPin(), Laelaps.WatchDog.WatchDog::cmdEnableAuxPort5V(), Laelaps.WatchDog.WatchDog::cmdEnableAuxPortBatt(), Laelaps.WatchDog.WatchDog::cmdEnableMotorCtlrs(), Laelaps.WatchDog.WatchDog::cmdGetFwVersion(), Laelaps.WatchDog.WatchDog::cmdPetTheDog(), Laelaps.WatchDog.WatchDog::cmdReadAPin(), Laelaps.WatchDog.WatchDog::cmdReadDPin(), Laelaps.WatchDog.WatchDog::cmdReadEnables(), Laelaps.WatchDog.WatchDog::cmdReadVoltages(), Laelaps.WatchDog.WatchDog::cmdResetRgbLed(), Laelaps.WatchDog.WatchDog::cmdSetAlarms(), Laelaps.WatchDog.WatchDog::cmdSetBatterySoC(), Laelaps.WatchDog.WatchDog::cmdSetRgbLed(), Laelaps.WatchDog.WatchDog::cmdWriteDPin(), and laelaps::LaeI2CMux::isOpen().

    {
      return m_i2c.fd >= 0? true: false;
    }

void laelaps::LaeI2C::lock ( )

inlineprotected

Lock the I²C bus.

The lock()/unlock() primitives provide safe multi-threading access.

Context:

Any.

Definition at line 221 of file laeI2C.h.

Referenced by close(), open(), read(), transfer(), write(), and write_read().

    {
      pthread_mutex_lock(&m_mutex);
    }

int LaeI2C::open ( const std::string &  strDevName )

virtual

Open I²C bus device.

Parameters

strDevName

I2C device name.

Returns

On success, OK(0) is returned.
On error, RC_ERROR(-1) is returned.

Definition at line 114 of file laeI2C.cxx.

References laelaps::getRealDeviceName(), laelaps::LAE_ECODE_NO_DEV, laelaps::LAE_OK, lock(), m_i2c, m_strDevName, and unlock().

Referenced by laelaps::i2cTryOpen().

{
  string  strDevNameReal;
  int     rc;

  lock();

  // Get the real device name, not any symbolic links.
  strDevNameReal  = getRealDeviceName(strDevName);

  if( i2c_open(&m_i2c, strDevNameReal.c_str()) < 0 )
  {
    LOGSYSERROR("%s.", strDevNameReal.c_str());
    rc = -LAE_ECODE_NO_DEV;
  }

  else
  {
    m_strDevName = strDevNameReal;

    LOGDIAG2("I2C device %s opened.", m_strDevName.c_str());

    rc = LAE_OK;
  }

  unlock();

  return rc;
}

int LaeI2C::read ( uint_t  addr, byte_t  buf[], size_t  len  )

virtual

Read from a I²C slave endpoint device.

Reads data from a device at the given address on the bound I²C bus.

Parameters

	addr	Endpoint I2C device's 7/10-bit address.
[out]	buf	Pointer to the buffer that will receive the data bytes.
	len	Number of bytes to read.

Returns

On success, returns ≥ 0 number of bytes read.
Else returns < 0 error code.

Definition at line 167 of file laeI2C.cxx.

References laelaps::LAE_ECODE_IO, lock(), m_i2c, and unlock().

Referenced by laelaps::LaeI2CMux::read(), and laelaps::LaeI2CMux::readChannelStates().

{
  int   n;

  lock();

  if( (n = i2c_read(&m_i2c, (i2c_addr_t)addr, buf, (uint_t)len)) < 0 )
  {
    // LOGSYSERROR
    LOGDIAG3("I2C: Slave device address 0x%02x: "
          "Failed to read from endpoint device data.",
          addr);
    n = -LAE_ECODE_IO;
  }

  else if( n != (int)len )
  {
    LOGWARN("I2C: Slave device address 0x%02x: "
          "Only %d/%d bytes read from endpoint device.",
          addr, n, (int)len);
  }

  unlock();

  return n;
}

int LaeI2C::transfer ( uint_t  addr, const byte_t  wbuf[], size_t  wlen, byte_t  rbuf[], size_t  rlen  )

virtual

Perform a write/read transfer to/from an I²C slave endpoint device.

An I²C tranfer sends/receives one or more messages before the STOP is issued to terminate the operation. Each message does begin with a START.

Note

Not all slave devices support this fast transfer protocol. If not, then use the write_read() instead.

Parameters

	addr	Endpoint I2C device's 7/10-bit address.
[in]	wbuf	Pointer to the buffer that contains the data to be written.
	wlen	Number of bytes to write.
[out]	rbuf	Pointer to the buffer that will receive the data.
	rlen	Number of bytes to read.

Returns

On success, OK(0) is returned.
On error, RC_ERROR(-1) is returned.

Definition at line 221 of file laeI2C.cxx.

References laelaps::LAE_ECODE_IO, laelaps::LAE_OK, lock(), m_i2c, and unlock().

{
  int   rc;

  lock();

  rc = i2c_transfer(&m_i2c, (i2c_addr_t)addr, wbuf, (uint_t)wlen,
                                              rbuf, (uint_t)rlen);

  if( rc < 0 )
  {
    LOGSYSERROR("I2C: Slave device address 0x%02x: "
          "Failed to perform write/read transaction.",
          addr);
    rc = -LAE_ECODE_IO;
  }

  else
  {
    rc = LAE_OK;
  }

  unlock();

  return rc;
}

void laelaps::LaeI2C::unlock ( )

inlineprotected

Unlock the I²C bus.

The lock()/unlock() primitives provide safe multi-threading access.

Context:

Any.

Definition at line 235 of file laeI2C.h.

References laelaps::i2cTryOpen().

Referenced by close(), open(), read(), transfer(), write(), and write_read().

    {
      pthread_mutex_unlock(&m_mutex);
    }

int LaeI2C::write ( uint_t  addr, const byte_t  buf[], size_t  len  )

virtual

Write to an I²C slave endpoint device.

Writes data to a device at the given address on the bound I²C bus.

Parameters

	addr	Endpoint I2C device's 7/10-bit address.
[in]	buf	Pointer to the buffer that will be written.
	len	Number of bytes to write.

Returns

On success, returns ≥ 0 number of bytes written.
Else returns < 0 error code.

Definition at line 194 of file laeI2C.cxx.

References laelaps::LAE_ECODE_IO, lock(), m_i2c, and unlock().

Referenced by laelaps::LaeWd::cmdConfigDPin(), laelaps::LaeWd::cmdConfigOperation(), laelaps::LaeWd::cmdEnableAuxPort5V(), laelaps::LaeWd::cmdEnableAuxPortBatt(), laelaps::LaeWd::cmdPetTheDog(), laelaps::LaeWd::cmdResetRgbLed(), laelaps::LaeWd::cmdSetAlarms(), laelaps::LaeWd::cmdSetBatterySoC(), laelaps::LaeWd::cmdSetRgbLed(), laelaps::LaeWd::cmdWriteAPin(), laelaps::LaeWd::cmdWriteDPin(), laelaps::LaeI2CMux::setChannel(), and laelaps::LaeI2CMux::write().

{
  int   n;

  lock();

  if( (n = i2c_write(&m_i2c, (i2c_addr_t)addr, buf, (uint_t)len)) < 0 )
  {
    // LOGSYSERROR
    LOGDIAG3("I2C: Slave device address 0x%02x: "
          "Failed to write to device data.",
          addr);
    n = -LAE_ECODE_IO;
  }

  else if( n != (int)len )
  {
    LOGWARN("I2C: Slave device address 0x%02x: "
          "Only %d/%d bytes written to endpoint device.",
          addr, n, (int)len);
  }

  unlock();

  return n;
}

int LaeI2C::write_read ( uint_t  addr, const byte_t  wbuf[], size_t  wlen, byte_t  rbuf[], size_t  rlen, long  usec = 0  )

virtual

Perform a write/read transaction to/from an I²C slave endpoint device.

Before each message a START is issued. After each message, a STOP is issued.

Parameters

	addr	Endpoint I2C device's 7/10-bit address.
[in]	wbuf	Pointer to the buffer that contains the data to be written.
	wlen	Number of bytes to write.
[out]	rbuf	Pointer to the buffer that will receive the data.
	rlen	Number of bytes to read.
	usec	Delay between write and read operations (usecs).

Returns

On success, OK(0) is returned.
On error, RC_ERROR(-1) is returned.

Definition at line 249 of file laeI2C.cxx.

References laelaps::LAE_ECODE_IO, laelaps::LAE_OK, lock(), m_i2c, and unlock().

Referenced by laelaps::LaeWd::cmdEnableMotorCtlrs(), sensor::vl6180::LaeRangeMuxSubproc::cmdGetAmbientLight(), laelaps::LaeWd::cmdGetFwVersion(), sensor::vl6180::LaeRangeMuxSubproc::cmdGetFwVersion(), sensor::vl6180::LaeRangeMuxSubproc::cmdGetIdent(), sensor::vl6180::LaeRangeMuxSubproc::cmdGetRanges(), sensor::vl6180::LaeRangeMuxSubproc::cmdGetTunes(), laelaps::LaeWd::cmdPetTheDog(), laelaps::LaeWd::cmdReadAPin(), laelaps::LaeWd::cmdReadDPin(), laelaps::LaeWd::cmdReadEnables(), laelaps::LaeWd::cmdReadVoltages(), laelaps::LaeWd::cmdTest(), sensor::vl6180::LaeRangeMuxSubproc::cmdTuneAls(), sensor::vl6180::LaeRangeMuxSubproc::cmdTuneToFSensor(), and laelaps::LaeI2CMux::transact().

{
  int   n;
  int   rc = LAE_OK;

  lock();

  //
  // Write.
  //
  if( wlen > 0 )
  {
    if( (n = i2c_write(&m_i2c, (i2c_addr_t)addr, wbuf, (uint_t)wlen)) < 0 )
    {
      // LOGSYSERROR
      LOGDIAG3("I2C: Slave device address 0x%02x: "
          "Failed to write to device data.",
          addr);
      rc = -LAE_ECODE_IO;
    }

    else if( n != (int)wlen )
    {
      LOGERROR("I2C: Slave device address 0x%02x: "
          "Only %d/%d bytes written to endpoint device.",
          addr, n, (int)wlen);
      rc = -LAE_ECODE_IO;
    }
  }

  //
  // Read.
  //
  if( (rlen > 0) && (rc == LAE_OK) )
  {
    // delay
    if( usec > 0 )
    {
      usleep(usec);
    }

    if( (n = i2c_read(&m_i2c, (i2c_addr_t)addr, rbuf, (uint_t)rlen)) < 0 )
    {
      // LOGSYSERROR
      LOGDIAG3("I2C: Slave device address 0x%02x: "
          "Failed to read from endpoint device data.",
          addr);
      rc = -LAE_ECODE_IO;
    }

    else if( n != (int)rlen )
    {
      LOGERROR("I2C: Slave device address 0x%02x: "
          "Only %d/%d bytes read from endpoint device.",
          addr, n, (int)rlen);
      rc = -LAE_ECODE_IO;
    }
  }

  unlock();

  return rc;
}

---

The documentation for this class was generated from the following files:

• include/Laelaps/laeI2C.h
• sw/liblaelaps/laeI2C.cxx