I'm using the Linux library. The only changes I made was to change the read and write calls to rawwrite and rawread. And then add ifdefs to i2c.h as follows:
#pragma once
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#ifdef USE_ESP32
#include <driver/i2c.h>
#define MAX_I2C_TX_BUFFER_LENGTH 0
#define MAX_I2C_RX_BUFFER_LENGTH 0
#define CONFIG_I2C_SLAVE_SCL 22
#define CONFIG_I2C_SLAVE_SDA 23
#define CONFIG_I2C_MASTER_FREQUENCY 400000
#define TICKS_TO_WAIT 1000 / portTICK_RATE_MS //TODO from example, how many ticks to wait??
#define ACK_CHECK_EN i2c_ack_type_t(0x1) /*!< I2C master will check ack from slave*/
#define ACK_CHECK_DIS i2c_ack_type_t(0x0) /*!< I2C master will not check ack from slave */
#define ACK_VAL i2c_ack_type_t(0x0) /*!< I2C ack value */
#define NACK_VAL i2c_ack_type_t( 0x1) /*!< I2C nack value */
#else
#include <linux/i2c-dev.h>
// heuristic to guess what version of i2c-dev.h we have:
// the one installed with `apt-get install libi2c-dev`
// would conflict with linux/i2c.h, while the stock
// one requires linus/i2c.h
#ifndef I2C_SMBUS_BLOCK_MAX
// If this is not defined, we have the "stock" i2c-dev.h
// so we include linux/i2c.h
#include <linux/i2c.h>
typedef unsigned char i2c_char_t;
#else
typedef char i2c_char_t;
#endif
#endif
#include <sys/ioctl.h>
#define MAX_BUF_NAME 64
class I2c
{
protected:
int i2C_bus;
int i2C_address;
int i2C_file;
public:
int initI2C_RW(int bus, int address, int file);
virtual int readI2C();
int rawread(uint8_t* buf, size_t length);
int rawwrite(char* buf, uint8_t length);
int closeI2C();
virtual ~I2c();
};
inline int I2c::rawread(uint8_t* buf, size_t length)
{
#ifdef USE_ESP32
int ret;
// return i2c_master_write_buffer(i2C_bus, buf, length, TICKS_TO_WAIT);
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
if((ret = i2c_master_start(cmd)))
{
printf("read i2c_master_start error %d\n", ret);
}
ret = i2c_master_write_byte(cmd, (i2C_address << 1) | I2C_MASTER_READ, ACK_CHECK_EN);
if(ret)
{
printf("read i2c_master_write_byte address error %d\n", ret);
}
if (length > 1) {
i2c_master_read(cmd, buf, length - 1, ACK_VAL);
}
ret = i2c_master_read_byte(cmd, buf + length - 1, NACK_VAL);
if(ret)
{
printf("read i2c_master_read_byte data error %d\n", ret);
}
i2c_master_stop(cmd);
ret = i2c_master_cmd_begin(i2C_bus, cmd, 1000 / portTICK_RATE_MS);
if(ret)
{
printf("rawread i2c_master_cmd_begin error %d\n", ret);
}
i2c_cmd_link_delete(cmd);
return ret ? ret : length;
#else
return ::read(i2C_file, buf, length);
#endif
}
inline int I2c::rawwrite(char* buf, uint8_t length)
{
#ifdef USE_ESP32
// return i2c_master_read_byte(i2C_bus, (uint8_t*)buf, length, TICKS_TO_WAIT);
int ret;
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
if((ret = i2c_master_start(cmd)))
{
printf("write i2c_master_start error %d\n", ret);
}
ret = i2c_master_write_byte(cmd, (i2C_address << 1) | I2C_MASTER_WRITE, ACK_CHECK_EN);
if(ret)
{
printf("write i2c_master_read_byte address error %d\n", ret);
}
ret = i2c_master_write(cmd, (uint8_t*)buf, length, ACK_CHECK_EN);
if(ret)
{
printf("write i2c_master_read_byte data error %d\n", ret);
}
if((ret = i2c_master_stop(cmd)))
{
printf("i2c_master_stop error %d\n", ret);
}
ret = i2c_master_cmd_begin(i2C_bus, cmd, 1000 / portTICK_RATE_MS);
if(ret)
{
printf("rawwrite error %d\n", ret);
}
i2c_cmd_link_delete(cmd);
return ret ? ret : length;
#else
return ::write(i2C_file, buf, length);
#endif
}
inline int I2c::initI2C_RW(int bus, int address, int fileHnd)
{
i2C_bus = bus;
i2C_address = address;
i2C_file = fileHnd;
#ifdef USE_ESP32
i2c_config_t conf;
conf.sda_io_num = CONFIG_I2C_SLAVE_SDA;
conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
conf.scl_io_num = CONFIG_I2C_SLAVE_SCL;
conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
conf.mode = I2C_MODE_MASTER;
//conf.slave.slave_addr = i2C_address;
conf.master.clk_speed = CONFIG_I2C_MASTER_FREQUENCY;
int ret;
ret = i2c_driver_install(i2C_bus, conf.mode, MAX_I2C_RX_BUFFER_LENGTH, MAX_I2C_TX_BUFFER_LENGTH, 0);
if(ret)
{
printf("Install failed %d\n", ret);
}
ret = i2c_param_config(i2C_bus, &conf);
if(ret)
{
printf("config failed %d\n", ret);
}
return ret;
#else
open I2C device as a file
char namebuf[MAX_BUF_NAME];
snprintf(namebuf, sizeof(namebuf), "/dev/i2c-%d", i2C_bus);
if ((i2C_file = open(namebuf, O_RDWR)) < 0)
{
fprintf(stderr, "Failed to open %s I2C Bus\n", namebuf);
return(1);
}
// target device as slave
if (ioctl(i2C_file, I2C_SLAVE, i2C_address) < 0){
fprintf(stderr, "I2C_SLAVE address %#x failed...", i2C_address);
return(2);
}
return 0;
#endif
}
inline int I2c::closeI2C()
{
#ifdef USE_ESP32
return i2c_driver_delete(i2C_bus);
#else
if(close(i2C_file)>0)
{
fprintf(stderr, "Failed to close file %d\n", i2C_file);
return 1;
}
return 0;
#endif
}
inline I2c::~I2c(){}
