i2c.c File Reference

I2C general purpose interface code for file system. More...

#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include "include/linux/i2c-dev.h"
#include "bbbandroidHAL.h"

Macros
#define	MAX_PATH   50

Functions
int	i2cOpenAdaptor (const uint8_t adaptorNumber)
int	i2cSetSlave (const int i2cFD, const uint8_t address)
int	i2cSetAddress (const int i2cFD, const uint8_t add)
int	i2cWriteByte (const int i2cFD, const uint8_t add, const uint8_t byte)
int	i2cWriteBytes (const int i2cFD, const uint8_t add, const int length, const uint8_t *bytes)
int	i2cReadByte (const int i2cFD, const uint8_t add)
int	i2cReadBytes (const int i2cFD, const uint8_t add, const int length, uint8_t *buff)
void	i2cClose (const int i2cFD)

Detailed Description

I2C general purpose interface code for file system.

Author

Ankur Yadav (ankur.nosp@m.ayad.nosp@m.av@gm.nosp@m.ail..nosp@m.com)

Macro Definition Documentation

#define MAX_PATH   50

Maximum buffer for creating path using snprintf()

Function Documentation

void i2cClose

(

const int

i2cFD

)

This function is used to close I2C file descriptor.

Parameters

i2cFD

a constant integer argument.

int i2cOpenAdaptor

(

const uint8_t

adaptorNumber

)

This function takes I2C adapter number as input and returns a file descriptor for accessing that I2C adapter.

Parameters

adaptorNumber

a constant uint8_t argument.

Returns

If successful then I2C file descriptor is returned and if it fails then -1 is returned.

int i2cReadByte	(	const int	i2cFD,
		const uint8_t	add
	)

It takes file descriptor and address of register from which data is to be read. It reads a byte from the address provided in input and returns the byte. It internally uses i2cSetAddress() to set pointer to proper address.

Parameters

i2cFD	a constant integer argument.
add	a constant uint8_t argument.

See Also

i2cSetAddress()

Returns

byte on success and -1 if it fails.

int i2cReadBytes	(	const int	i2cFD,
		const uint8_t	add,
		const int	length,
		uint8_t *	buff
	)

It takes file descriptor, starting address of register from which data is to be read, length of data to be read and buffer to store the data as input. It is used to get 'length' number of bytes in 'buff' array from 'add' starting address.

Parameters

i2cFD	a constant integer argument.
add	a constant uint8_t argument.
length	a constant integer argument.
bytes	an uint8_t pointer argument.

Returns

0 on success and -1 if it fails.

int i2cSetAddress	(	const int	i2cFD,
		const uint8_t	add
	)

This is used by some other functions internally for random access of sensor registers. It takes file descriptor and random address as input to which file descriptor should point.

Parameters

i2cFD	a constant integer argument.
add	a constant uint8_t argument.

Returns

0 on success and -1 if it fails.

int i2cSetSlave	(	const int	i2cFD,
		const uint8_t	address
	)

This takes I2C adapter file descriptor and address at which device is attached as input and sets slave for file descriptor using ioctl call.

Parameters

i2cFD	a constant integer argument.
address	a constant uint8_t argument.

Returns

If successful then 0 is returned and if it fails then -1 is returned.

int i2cWriteByte	(	const int	i2cFD,
		const uint8_t	add,
		const uint8_t	byte
	)

This function takes file descriptor, address of register to write and byte to be written as input and writes byte provided in the argument at the address provided.

Parameters

i2cFD	a constant integer argument.
add	a constant uint8_t argument.
byte	a constant uint8_t argument.

Returns

0 on success and -1 if it fails.

int i2cWriteBytes	(	const int	i2cFD,
		const uint8_t	add,
		const int	length,
		const uint8_t *	bytes
	)

It takes i2c file descriptor, start address of registers to be written, length of data and array containing bytes of data as input. This function is used to write bytes provided in argument from the address provided to address+length continuously.

Parameters

i2cFD	a constant integer argument.
add	a constant uint8_t argument.
length	a constant integer argument.
bytes	a constant uint8_t pointer argument.

Returns

0 on success and -1 if it fails.