m2mb_i2c.h File Reference

I2C library implementation. More...

Go to the source code of this file.

Data Structures
struct	M2MB_I2C_MSG
struct	M2MB_I2C_RDWR_IOCTL_DATA
struct	M2MB_I2C_CFG_T

Macros
#define	NULL   0
#define	I2C_M_WR   0x0000 /* write data, from master to slave */
#define	I2C_M_RD   0x0001 /* read data, from slave to master */

Enumerations
enum	M2MB_I2C_IOCTL_REQUEST { M2MB_I2C_IOCTL_SET_CFG, M2MB_I2C_IOCTL_GET_CFG, M2MB_I2C_IOCTL_RDWR }

Functions
INT32	m2mb_i2c_open (const CHAR *path, INT32 flags,...)
	open an I2C device More...
INT32	m2mb_i2c_close (INT32 fd)
	close an I2C device More...
INT32	m2mb_i2c_ioctl (INT32 fd, INT32 request,...)
	configure, read from and/or write to an I2C device More...
SSIZE_T	m2mb_i2c_read (INT32 fd, void *buf, SIZE_T nbyte)
	read from an I2C device More...
SSIZE_T	m2mb_i2c_write (INT32 fd, const void *buf, SIZE_T nbyte)
	write to an I2C device More...

Detailed Description

I2C library implementation.

m2m/m2m_generic/common/m2mb_inc/m2mb_i2c.h

The following functions are implemented: m2mb_i2c_ioctl m2mb_i2c_open m2mb_i2c_read m2mb_i2c_write m2mb_i2c_close

@notes Dependencies: m2m/m2m_generic/common/m2mb_inc/m2mb_types.h

Author

Morgan Deidda

@changes Enrico Perini

Date

31/08/2017

Function Documentation

m2mb_i2c_close()

INT32 m2mb_i2c_close

(

INT32

fd

)

close an I2C device

This function closes a I2C device (from 1 to 10)

Parameters

[in]

fd

file descriptor returned by m2mb_i2c_open

Returns

0 on SUCCESS negative number on FAILURE Example

ret = m2mb_i2c_close( fd );

m2mb_i2c_ioctl()

INT32 m2mb_i2c_ioctl	(	INT32	fd,
		INT32	request,
			...
	)

configure, read from and/or write to an I2C device

Depending on request parameter, this function can configure an I2C device, or can send and/or receive data through I2C combined format

Parameters

[in]	fd	file descriptor returned by m2mb_i2c_open
[in]	request	required operation (see M2MB_I2C_IOCTL_REQUEST)
[in]	cfg	pointer to the configuration struct M2MB_I2C_CFG_T casted to void* The parameters depend on request code: if request == M2MB_I2C_IOCTL_SET_CFG: SDA and SCL pins are mapped on GPIOs, and the register of the device from which reading or to which writing is set; in struct M2MB_I2C_CFG_T, sdaPin, sclPin and registerId are mandatory if request == M2MB_I2C_IOCTL_RDWR: reading and writing through I2C combined format; in struct M2MB_I2C_CFG_T, rw_param is mandatory if request == M2MB_I2C_IOCTL_GET_CFG: a pointer to the structure M2MB_I2C_CFG_T previously set is got

Returns

0 on SUCCESS if request == M2MB_I2C_IOCTL_SET_CFG or request == M2MB_I2C_IOCTL_GET_CFG number of written Bytes on SUCCESS if request == M2MB_I2C_IOCTL_RDWR and the function is used only for writing number of read Bytes on SUCCESS if request == M2MB_I2C_IOCTL_RDWR and the function is used only for reading or both for writing and reading -1 on FAILURE

Example

M2MB_I2C_CFG_T i2c_data;
i2c_data.sdaPin = 2; //SDA pin on GPIO_02
i2c_data.sclPin = 3; //SCL pin on GPIO_03
i2c_data.registerId = 4; //register to write to or to read from: 0x04
i2c_data.rw_param = (M2MB_I2C_RDWR_IOCTL_DATA*) m2mb_os_malloc( sizeof(M2MB_I2C_RDWR_IOCTL_DATA) );
 
Ret = m2mb_i2c_ioctl( fd, M2MB_I2C_IOCTL_SET_CFG, (void *)&i2c_data );
if ( Ret )
{
  m2mb_trace_printf(M2MB_TC_M2M_USER, M2MB_TL_ERROR, " m2mb_i2c_ioctl() - I2C FAIL" );
  testErrs = 1;
}

//write 2 bytes starting from register 0x04
M2MB_I2C_CFG_T i2c_data;
i2c_data.registerId = 0x4;
memset( iicbuf_wr, 0x00, 256 );
memset( iicbuf_rd, 0x00, 256 );
iicbuf_wr[0] = i2c_data.registerId;  //first send register id
iicbuf_wr[1] = 0xaa;  //data to write in register 0x04
iicbuf_wr[2] = 0xbb;  //data to write to register 0x05
msgs[0].buf = iicbuf_wr;
msgs[0].flags = I2C_M_WR;
msgs[0].len = 3; //send 1 data to external device
msgs[1].flags = I2C_M_RD;
msgs[1].len = 0; //read 10 bytes starting fom 0x4 register
msgs[1].buf = iicbuf_rd;
i2c_data.rw_param->msgs = &msgs[0];
i2c_data.rw_param->nmsgs = 1; //both writing and reading
IICres =  m2mb_i2c_ioctl(fd, M2MB_I2C_IOCTL_RDWR, (void *)&i2c_data);

//read 2 bytes starting fom 0x4 register
M2MB_I2C_CFG_T i2c_data;
i2c_data.registerId = 0x4;
memset( iicbuf_wr, 0x00, 256 );
memset( iicbuf_rd, 0x00, 256 );
iicbuf_wr[0] = i2c_data.registerId;  //first send register id
msgs[0].buf = iicbuf_wr;
msgs[0].flags = I2C_M_WR;
msgs[0].len = 1; //send 1 data to external device
msgs[1].flags = I2C_M_RD;
msgs[1].len = 2;
msgs[1].buf = iicbuf_rd;
i2c_data.rw_param->msgs = &msgs[0];
i2c_data.rw_param->nmsgs = 2; //both writing and reading
IICres =  m2mb_i2c_ioctl(fd, M2MB_I2C_IOCTL_RDWR, (void *)&i2c_data);

m2mb_i2c_open()

INT32 m2mb_i2c_open	(	const CHAR *	path,
		INT32	flags,
			...
	)

open an I2C device

This function opens a I2C device (from 1 to 10)

Parameters

[in]	path	the path has a string of this type: /dev/I2C-# where # is in decimal format I2C address is in 8 bit format, where last bit is the R/W flag
[in]	flags	currently unused

Returns

file descriptor on SUCCESS -1 on FAILURE

Example

fd = m2mb_i2c_open( "/dev/I2C-212", 0 ); // device address 0xD4 (8 bit format)

m2mb_i2c_read()

SSIZE_T m2mb_i2c_read	(	INT32	fd,
		void *	buf,
		SIZE_T	nbyte
	)

read from an I2C device

This function reads nbyte Bytes from a I2C device into the array pointed to by buf

Parameters

[in]	fd	file descriptor returned by m2mb_i2c_open
[in]	buf	destination buffer, previously allocated
[in]	nbyte	length of destination buffer in Bytes

Returns

number of read Bytes on SUCCESS -1 on FAILURE

Example

IICres = m2mb_i2c_read(fd, iicbuf, 32);
if ( IICres == -1 ) m2mb_trace_printf(M2MB_TC_M2M_USER, M2MB_TL_ERROR, "I2C read FAIL" );
else
{
  if ( IICres != 32 )
    m2mb_trace_printf(M2MB_TC_M2M_USER, M2MB_TL_ERROR, "I2C read FAIL" );
}

m2mb_i2c_write()

SSIZE_T m2mb_i2c_write	(	INT32	fd,
		const void *	buf,
		SIZE_T	nbyte
	)

write to an I2C device

This function writes nbyte Bytes from the array pointed to by buf to a I2C device

Parameters

[in]	fd	file descriptor returned by m2mb_i2c_open
[in]	buf	source buffer, previously allocated
[in]	nbyte	length of source buffer in Bytes

Returns

number of written Bytes on SUCCESS -1 on FAILURE

Example

//writes 2 bites from register set with m2mb_i2c_ioctl
memset( iicbuf_wr, 0x00, 256 );
iicbuf_wr[0] = 0;
iicbuf_wr[1] = 16;
IICres = m2mb_i2c_write(fd, iicbuf_wr, 2);