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#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <linux/types.h>
#include <i2c-api.h>
#define I2C_MAX_BUS 8
static i2c_bus_t ds[I2C_MAX_BUS];
static int i2c_bus_cnt = 0;
int i2c_get_major_i2c( int *major )
{
FILE *fp;
char linebuff[128];
char device_name[32];
int tmp_major;
fp = fopen("/proc/devices", "r");
if(fp == NULL) return I2C_NOT_FIND_MAJOR;
while(1)
{
if( fgets(linebuff, sizeof( linebuff) , fp ) == NULL ) break;
if (sscanf(linebuff, "%d %s", &tmp_major, device_name) == 2)
{
if (strcmp("i2c", device_name) == 0)
{
*major = tmp_major;
fclose( fp );
return I2C_NO_ERROR;
}
}
}
fclose( fp );
return I2C_NOT_FIND_MAJOR;
}
int i2c_make_bus_node( int major, int bn )
{
sprintf(ds[bn].node_fname, "/dev/i2cbus%d-%d", getpid(), bn );
mknod(ds[bn].node_fname, (S_IRWXU|S_IRWXG|S_IFCHR), (major<<8) + bn );
ds[bn].fd = open(ds[bn].node_fname, O_RDWR );
", ds[bn].node_fname, bn, ds[bn].fd );
unlink(ds[bn].node_fname);
return ds[bn].fd;
}
//------------------------------------------------------------------------------
// 설명 : I2C API 를 초기화 한다.
//------------------------------------------------------------------------------
int i2c_init( void )
{
int major;
int ret;
int lp;
ret = i2c_get_major_i2c( &major );
if( I2C_NOT_FIND_MAJOR == ret )
{
printf( "can't find nodfile
" );
return -1;
}
//printf( "I2C Major Numner = %d
", major );
i2c_bus_cnt = 0;
for( lp = 0; lp < I2C_MAX_BUS; lp++ )
{
if( i2c_make_bus_node( major, lp ) >= 0 )
{
i2c_bus_cnt++;
}
else
{
ds[lp].fd = -1;
}
}
return 0;
}
//------------------------------------------------------------------------------
// 설명 : 현재 존재하는 I2C BUS 수를 얻는다.
// 반환 : 소켓 수
//------------------------------------------------------------------------------
int i2c_get_bus_count( void )
{
return i2c_bus_cnt;
}
//------------------------------------------------------------------------------
// 설명 : I2C 버스에서 읽는다.
//------------------------------------------------------------------------------
int i2c_read_data( access_data_t * access_data )
{
if( ds[access_data->bus].fd < 0 ) return I2C_NOT_FIND_BUS;
if( access_data->size > sizeof( access_data->data ) ) access_data->size = sizeof( access_data->data );
ioctl( ds[access_data->bus].fd, I2C_SLAVE, access_data->addr );
access_data->size = read( ds[access_data->bus].fd, access_data->data, access_data->size );
if( access_data->size < 0 ) return I2C_READ_DEVICE;
return I2C_NO_ERROR;
}
//------------------------------------------------------------------------------
// 설명 : I2C 버스에 데이터를 써 넣는다.
//------------------------------------------------------------------------------
int i2c_write_data( access_data_t * access_data )
{
if( ds[access_data->bus].fd < 0 ) return I2C_NOT_FIND_BUS;
if( access_data->size > sizeof( access_data->data ) ) access_data->size = sizeof( access_data->data );
ioctl( ds[access_data->bus].fd, I2C_SLAVE, access_data->addr );
access_data->size = write( ds[access_data->bus].fd, access_data->data, access_data->size );
if( access_data->size < 0 ) return I2C_WRITE_DEVICE;
return I2C_NO_ERROR;
}
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