smbus.c File Reference

System Management Bus (SMBus) over I²C communication interface. More...

#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include "rnr/rnrconfig.h"
#include "rnr/i2c-dev.h"
#include "rnr/smbus.h"

Go to the source code of this file.

Functions
int	i2c_smbus_access (int fd, byte_t read_write, byte_t command, int size, i2c_smbus_data_t *data)
	Execute an SMBus IOCTL. More...
int	i2c_smbus_write_quick (int fd, byte_t value)
	Write a quick value to the SMBus. More...
int	i2c_smbus_read_byte (int fd)
	Read an immediate byte from the SMBus. More...
int	i2c_smbus_write_byte (int fd, byte_t value)
	Write an immediate byte to the SMBus. More...
int	i2c_smbus_read_byte_data (int fd, byte_t command)
	Read a data byte from the SMBus. More...
int	i2c_smbus_write_byte_data (int fd, byte_t command, byte_t value)
	Write a data byte to the SMBus. More...
int	i2c_smbus_read_word_data (int fd, byte_t command)
	Read a data 2-byte word from the SMBus. More...
int	i2c_smbus_write_word_data (int fd, byte_t command, ushort_t value)
	Write a data 2-byte word to the SMBus. More...
int	i2c_smbus_process_call (int fd, byte_t command, ushort_t value)
	Issue a 2-byte word process call (write/read) to the SMBus. More...
int	i2c_smbus_read_block_data (int fd, byte_t command, byte_t *values)
	Read a block of data from the SMBus. More...
int	i2c_smbus_write_block_data (int fd, byte_t command, byte_t length, const byte_t *values)
	Write a data block to the SMBus. More...
int	i2c_smbus_read_i2c_block_data (int fd, byte_t command, byte_t *values)
	Read a block of data from the SMBus via low-level I2C. More...
int	i2c_smbus_write_i2c_block_data (int fd, byte_t command, byte_t length, const byte_t *values)
	Write a block of data to the SMBus via low-level I2C. More...
int	i2c_smbus_block_process_call (int fd, byte_t command, byte_t length, byte_t *values)
	Issue a block process call (write/read) to the SMBus. More...

Detailed Description

System Management Bus (SMBus) over I²C communication interface.

LastChangedDate

2009-09-09 09:44:12 -0600 (Wed, 09 Sep 2009)

Rev

130

Author

Robin Knight (robin.nosp@m..kni.nosp@m.ght@r.nosp@m.oadn.nosp@m.arrow.nosp@m.s.co.nosp@m.m)

Copyright

© 2009-2017. RoadNarrows LLC.
http://www.roadnarrows.com
All Rights Reserved

---

Original Source and Copyright:

See i2c-dev.h.

---

Definition in file smbus.c.

Function Documentation

int i2c_smbus_access	(	int	fd,
		byte_t	read_write,
		byte_t	command,
		int	size,
		i2c_smbus_data_t *	data
	)

Execute an SMBus IOCTL.

Parameters

	fd	File descriptor to opened SMBus device.
	read_write	Operation access type.
	command	Operation command or immediate data.
	size	Data size.
[in,out]	data	Read/write/control data

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 81 of file smbus.c.

References i2c_smbus_ioctl_data_struct::command, i2c_smbus_ioctl_data_struct::data, I2C_SMBUS, i2c_smbus_ioctl_data_struct::read_write, and i2c_smbus_ioctl_data_struct::size.

Referenced by i2c_smbus_block_process_call(), i2c_smbus_process_call(), i2c_smbus_read_block_data(), i2c_smbus_read_byte(), i2c_smbus_read_byte_data(), i2c_smbus_read_i2c_block_data(), i2c_smbus_read_word_data(), i2c_smbus_write_block_data(), i2c_smbus_write_byte(), i2c_smbus_write_byte_data(), i2c_smbus_write_i2c_block_data(), i2c_smbus_write_quick(), and i2c_smbus_write_word_data().

{
  i2c_smbus_ioctl_data_t  args;

  args.read_write = read_write;
  args.command    = command;
  args.size       = size;
  args.data       = data;

  return ioctl(fd, I2C_SMBUS, &args);
}

int i2c_smbus_block_process_call	(	int	fd,
		byte_t	command,
		byte_t	length,
		byte_t *	values
	)

Issue a block process call (write/read) to the SMBus.

Parameters

	fd	File descriptor to opened SMBus device.
	command	Command to SMBus device.
	length	Length of buffer (bytes) to write.
[in,out]	values	Buffer of data to write and to hold the block of read byte values. Must be large enough to receive the data.

Returns

On success, returns ≥ 0 the number of bytes read, excluding any header fields. Else errno is set appropriately and -1 is returned.

Definition at line 396 of file smbus.c.

References i2c_smbus_data_union::block, i2c_smbus_access(), I2C_SMBUS_BLOCK_MAX, I2C_SMBUS_BLOCK_PROC_CALL, and I2C_SMBUS_WRITE.

{
  i2c_smbus_data_t  data;
  int               i;
  int               rc;

  if( length > I2C_SMBUS_BLOCK_MAX )
  {
    length = I2C_SMBUS_BLOCK_MAX;
  }

  for(i=1; i<=length; i++)
  {
    data.block[i] = values[i-1];
  }
  data.block[0] = length;

  rc = i2c_smbus_access(fd, I2C_SMBUS_WRITE, command, I2C_SMBUS_BLOCK_PROC_CALL,
                          &data);

  if( rc >= 0 )
  {
    for(i=1; i<=data.block[0]; i++)
    {
      values[i-1] = data.block[i];
    }
    rc = data.block[0];
  }

  return rc;
}

int i2c_smbus_process_call	(	int	fd,
		byte_t	command,
		ushort_t	value
	)

Issue a 2-byte word process call (write/read) to the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
command	Command to SMBus device.
value	Word value to write.

Returns

Returns read 2-byte word on on success. Else errno is set appropriately and -1 is returned.

Definition at line 238 of file smbus.c.

References i2c_smbus_access(), I2C_SMBUS_PROC_CALL, I2C_SMBUS_WRITE, and i2c_smbus_data_union::word.

{
  i2c_smbus_data_t  data;
  int               rc;

  data.word = value;

  rc = i2c_smbus_access(fd, I2C_SMBUS_WRITE, command, I2C_SMBUS_PROC_CALL,
                        &data);

  return rc>=0? 0x0FFFF & data.word: -1;
}

int i2c_smbus_read_block_data	(	int	fd,
		byte_t	command,
		byte_t *	values
	)

Read a block of data from the SMBus.

Parameters

	fd	File descriptor to opened SMBus device.
	command	Command to SMBus device.
[out]	values	Buffer to hold the block of read byte values. Must be large enough to receive the data.

Returns

On success, returns ≥ 0 the number of bytes read, excluding any header fields. Else errno is set appropriately and -1 is returned.

Definition at line 264 of file smbus.c.

References i2c_smbus_data_union::block, i2c_smbus_access(), I2C_SMBUS_BLOCK_DATA, and I2C_SMBUS_READ.

{
  i2c_smbus_data_t  data;
  int               i;
  int               rc;

  rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_BLOCK_DATA,
                          &data);

  if( rc >= 0 )
  {
    for(i=1; i<=data.block[0]; ++i)
    {
      values[i-1] = data.block[i];
    }
    rc = data.block[0];
  }

  return rc;
}

int i2c_smbus_read_byte

(

int

fd

)

Read an immediate byte from the SMBus.

Parameters

fd	File descriptor to opened SMBus device.

Returns

Returns read byte on on success. Else errno is set appropriately and -1 is returned.

Definition at line 118 of file smbus.c.

References i2c_smbus_data_union::byte, I2C_NOCMD, i2c_smbus_access(), I2C_SMBUS_BYTE, and I2C_SMBUS_READ.

{
  i2c_smbus_data_t  data;
  int               rc;

  rc = i2c_smbus_access(fd, I2C_SMBUS_READ, I2C_NOCMD, I2C_SMBUS_BYTE, &data);

  return rc>=0? 0x0FF & data.byte: -1;
}

int i2c_smbus_read_byte_data	(	int	fd,
		byte_t	command
	)

Read a data byte from the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
command	Command to SMBus device.

Returns

Returns read byte on on success. Else errno is set appropriately and -1 is returned.

Definition at line 153 of file smbus.c.

References i2c_smbus_data_union::byte, i2c_smbus_access(), I2C_SMBUS_BYTE_DATA, and I2C_SMBUS_READ.

{
  i2c_smbus_data_t  data;
  int               rc;

  rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_BYTE_DATA,
                              &data);

  return rc>=0? 0x0FF & data.byte: -1;
}

int i2c_smbus_read_i2c_block_data	(	int	fd,
		byte_t	command,
		byte_t *	values
	)

Read a block of data from the SMBus via low-level I²C.

Parameters

	fd	File descriptor to opened SMBus device.
	command	Command to SMBus device.
[out]	values	Buffer to hold the block of read byte values. Must be large enough to receive the data.

Returns

On success, returns ≥ 0 the number of bytes read, excluding any header fields. Else errno is set appropriately and -1 is returned.

Definition at line 330 of file smbus.c.

References i2c_smbus_data_union::block, i2c_smbus_access(), I2C_SMBUS_I2C_BLOCK_DATA, and I2C_SMBUS_READ.

{
  i2c_smbus_data_t  data;
  int               i;
  int               rc;

  rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_I2C_BLOCK_DATA,
                        &data);
  if( rc >= 0 )
  {
    for(i=1; i<=data.block[0]; i++)
    {
      values[i-1] = data.block[i];
    }
    rc = data.block[0];
  }
  return rc;
}

int i2c_smbus_read_word_data	(	int	fd,
		byte_t	command
	)

Read a data 2-byte word from the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
command	Command to SMBus device.

Returns

Returns read 2-byte word on on success. Else errno is set appropriately and -1 is returned.

Definition at line 195 of file smbus.c.

References i2c_smbus_access(), I2C_SMBUS_READ, I2C_SMBUS_WORD_DATA, and i2c_smbus_data_union::word.

{
  i2c_smbus_data_t  data;
  int               rc;

  rc = i2c_smbus_access(fd, I2C_SMBUS_READ, command, I2C_SMBUS_WORD_DATA,
                          &data);

  return rc>=0? 0x0FFFF & data.word: -1;
}

int i2c_smbus_write_block_data	(	int	fd,
		byte_t	command,
		byte_t	length,
		const byte_t *	values
	)

Write a data block to the SMBus.

Parameters

	fd	File descriptor to opened SMBus device.
	command	Command to SMBus device.
	length	Length of buffer (bytes) to write.
[in]	values	Buffer of data to write.

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 297 of file smbus.c.

References i2c_smbus_data_union::block, i2c_smbus_access(), I2C_SMBUS_BLOCK_DATA, I2C_SMBUS_BLOCK_MAX, and I2C_SMBUS_WRITE.

{
  i2c_smbus_data_t  data;
  int               i;

  if( length > I2C_SMBUS_BLOCK_MAX )
  {
    length = I2C_SMBUS_BLOCK_MAX;
  }

  for(i=1; i<=length; i++)
  {
    data.block[i] = values[i-1];
  }
  data.block[0] = length;

  return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_BLOCK_DATA, &data);
}

int i2c_smbus_write_byte	(	int	fd,
		byte_t	value
	)

Write an immediate byte to the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
value	Byte value to write.

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 138 of file smbus.c.

References i2c_smbus_access(), I2C_SMBUS_BYTE, and I2C_SMBUS_WRITE.

{
  return i2c_smbus_access(fd, I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
}

int i2c_smbus_write_byte_data	(	int	fd,
		byte_t	command,
		byte_t	value
	)

Write a data byte to the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
command	Command to SMBus device.
value	Byte value to write.

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 175 of file smbus.c.

References i2c_smbus_data_union::byte, i2c_smbus_access(), I2C_SMBUS_BYTE_DATA, and I2C_SMBUS_WRITE.

{
  i2c_smbus_data_t  data;

  data.byte = value;

  return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_BYTE_DATA, &data);
}

int i2c_smbus_write_i2c_block_data	(	int	fd,
		byte_t	command,
		byte_t	length,
		const byte_t *	values
	)

Write a block of data to the SMBus via low-level I²C.

Parameters

	fd	File descriptor to opened SMBus device.
	command	Command to SMBus device.
	length	Length of buffer (bytes) to write.
[in]	values	Buffer of data to write.

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 361 of file smbus.c.

References i2c_smbus_data_union::block, i2c_smbus_access(), I2C_SMBUS_I2C_BLOCK_DATA, I2C_SMBUS_I2C_BLOCK_MAX, and I2C_SMBUS_WRITE.

{
  i2c_smbus_data_t  data;
  int               i;

  if( length > I2C_SMBUS_I2C_BLOCK_MAX )
  {
    length = I2C_SMBUS_I2C_BLOCK_MAX;
  }

  for(i=1; i<=length; i++)
  {
    data.block[i] = values[i-1];
  }
  data.block[0] = length;

  return i2c_smbus_access(fd, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_I2C_BLOCK_DATA, &data);
}

int i2c_smbus_write_quick	(	int	fd,
		byte_t	value
	)

Write a quick value to the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
value	Value to write

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 104 of file smbus.c.

References I2C_NOCMD, i2c_smbus_access(), and I2C_SMBUS_QUICK.

{
  return i2c_smbus_access(fd, value, I2C_NOCMD, I2C_SMBUS_QUICK, NULL);
}

int i2c_smbus_write_word_data	(	int	fd,
		byte_t	command,
		ushort_t	value
	)

Write a data 2-byte word to the SMBus.

Parameters

fd	File descriptor to opened SMBus device.
command	Command to SMBus device.
value	Word value to write.

Returns

Returns ≥ 0 on success. Else errno is set appropriately and -1 is returned.

Definition at line 217 of file smbus.c.

References i2c_smbus_access(), I2C_SMBUS_WORD_DATA, I2C_SMBUS_WRITE, and i2c_smbus_data_union::word.

{
  i2c_smbus_data_t  data;

  data.word = value;

  return i2c_smbus_access(fd, I2C_SMBUS_WRITE,  command,
                          I2C_SMBUS_WORD_DATA, &data);
}