i2ccom.h File Reference

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Data Structures
struct	i2c_t
Typedefs
typedef unsigned int	i2c_dev_t
Functions
int	i2c_open (i2c_t *i2c, const char *device)
void	i2c_close (i2c_t *i2c)
int	i2c_llread (i2c_t *i2c, i2c_dev_t dev, char *buf, unsigned int len)
int	i2c_llwrite (i2c_t *i2c, i2c_dev_t dev, const char *buf, unsigned int len)
int	i2c_lltransfer (i2c_t *i2c, i2c_dev_t dev, const char *write_buf, unsigned int write_len, char *read_buf, unsigned int read_len)
int	i2c_exists (i2c_t *i2c, i2c_dev_t dev)
int	i2c_scan (i2c_t *i2c, int(*callback)(i2c_t *i2c, i2c_dev_t dev, void *context), void *context)

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Detailed Description

I²C Low-Level Communication Layer

Definition in file i2ccom.h.

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Typedef Documentation

typedef unsigned int i2c_dev_t

I²C Device Address Definition

Definition at line 20 of file i2ccom.h.

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Function Documentation

void i2c_close

(

i2c_t *

i2c

)

This procedure closes an I²C Bus.

Parameters:

i2c

I²C Bus Handle

Definition at line 87 of file i2ccom.c.

References i2c_t::fd.

Referenced by knet_i2c_exit(), and knet_i2c_init().

int i2c_exists	(	i2c_t *	i2c,
		i2c_dev_t	dev
	)

This function verifies the existance of a given device on a given I²C Bus.

Parameters:

	i2c	I²C Bus Handle.
	dev	I²C Device Address. This value contains only the I²C address bits (7-bit or 10-bit).

Returns:

A value indicating if a device is present or not:

• 1 device present
• 0 no device present

Definition at line 243 of file i2ccom.c.

References i2c_t::fd.

Referenced by knet_i2c_open().

int i2c_llread	(	i2c_t *	i2c,
		i2c_dev_t	dev,
		char *	buf,
		unsigned int	len
	)

This function is the primitive to read data from a given device on a given I²C Bus.

Parameters:

	i2c	I²C Bus Handle
	dev	I²C Device Address. This value contains only the I²C address bits (7-bit or 10-bit).
	buf	Pointer to the buffer that will receive the data bytes.
	len	Size of the buffer in bytes.

Returns:

an error code:

• <0 standard error number. See errno.h
• >=0 number of bytes read

Definition at line 138 of file i2ccom.c.

References i2c_t::fd, and i2c_priv_select_device().

Referenced by knet_i2c_read().

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int i2c_lltransfer	(	i2c_t *	i2c,
		i2c_dev_t	dev,
		const char *	write_buf,
		unsigned int	write_len,
		char *	read_buf,
		unsigned int	read_len
	)

This function is the primitive to write data to and then read data from a given device on a given I²C Bus.

Parameters:

	i2c	I²C Bus Handle.
	dev	I²C Device Address. This value contains only the I²C address bits (7-bit or 10-bit).
	write_buf	Pointer to the buffer that contains the data to be written.
	write_len	Number of bytes to write. The data are in the write buffer.
	read_buf	Pointer to the buffer that will receive the data.
	read_len	Size of the read buffer in bytes.

Returns:

an error code:

• <0 standard error code. See errno.h
• >=0 on success

Definition at line 202 of file i2ccom.c.

References i2c_t::fd.

Referenced by knet_i2c_transfer().

int i2c_llwrite	(	i2c_t *	i2c,
		i2c_dev_t	dev,
		const char *	buf,
		unsigned int	len
	)

This function is the primitive to write data to a given device on a given I²C Bus.

Parameters:

	i2c	I²C Bus Handle
	dev	I²C Device Address. This value contains only the I²C address bits (7-bit or 10-bit).
	buf	Pointer to the buffer that will be written.
	len	Number of bytes to write

Returns:

an error code:

• <0 standard error number. See errno.h
• >=0 number of bytes written

Definition at line 166 of file i2ccom.c.

References i2c_t::fd, and i2c_priv_select_device().

Referenced by knet_i2c_write().

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int i2c_open	(	i2c_t *	i2c,
		char const *	device
	)

This function opens an I²C Bus.

Parameters:

	i2c	Pointer to I²C Bus Descriptor. This descriptor must be allocated by the caller.
	device	A string representing the device name. A NULL should be used for default I²C Bus. (e.g. /dev/i2c/0)

Returns:

an error code

• <0 standard error number. See errno.h
• 0 if I²C Bus Device has been opened

Definition at line 66 of file i2ccom.c.

References i2c_t::dev, and i2c_t::fd.

Referenced by knet_i2c_init().

int i2c_scan	(	i2c_t *	i2c,
		int(*)(i2c_t *i2c, i2c_dev_t dev, void *context)	callback,
		void *	context
	)

This function scans a given I²C Bus to find devices

Parameters:

	i2c	I²C Bus Handle.
	callback	A callback function called when a device is found. If this callback function returns a value <0 the bus scan stops immedialety and the value is used as return value by i2c_scan.
	context	A value or a pointer passed to the callback function.

Returns:

an error code:

• <0 standard error code (See errno.h) or a user error code.
• >=0 Number of devices found on the I²C bus.

Definition at line 280 of file i2ccom.c.

References i2c_t::fd.

Referenced by knet_i2c_init().