How to operate at24c32 by smbus in linux? - linux-kernel

Question

What if the EEPROM used is greater than 32K, such as at24c32, and the register address is 16bit? It seems that smbus only supports 8bit registers?
I can read 0xff, but the written content will return - 5, which fails.
I want to know whether the kernel only supports 8-bit registers, but not 16 bit registers?
This is my code:
#include <fcntl.h>
#include <stdio.h>
#include <linux/i2c-dev.h>
#include <errno.h>
#include <stddef.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <stdint.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <errno.h>
#include <signal.h>
#define AT24C32_ADDR 0x53
__s32 i2c_smbus_access(int file, char read_write, __u8 command,
int size, union i2c_smbus_data* data)
{
struct i2c_smbus_ioctl_data args;
__s32 err;
args.read_write = read_write;
args.command = command;
args.size = size;
args.data = data;
err = ioctl(file, I2C_SMBUS, &args);
if (err == -1)
err = -errno;
return err;
}
__s32 i2c_smbus_write_byte_data(int file, __u8 command, __u8 value)
{
union i2c_smbus_data data;
data.byte = value;
return i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
I2C_SMBUS_BYTE_DATA, &data);
}
__s32 i2c_smbus_read_byte_data(int file, __u8 command)
{
union i2c_smbus_data data;
int err;
err = i2c_smbus_access(file, I2C_SMBUS_READ, command,
I2C_SMBUS_BYTE_DATA, &data);
if (err < 0)
return err;
return 0x0FF & data.byte;
}
static int32_t i2c_smbus_write_word_data(int file, uint8_t cmd, uint16_t value)
{
union i2c_smbus_data data;
data.word = value;
return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
I2C_SMBUS_WORD_DATA, &data);
}
static int32_t i2c_smbus_read_word_data(int fd, uint8_t cmd)
{
union i2c_smbus_data data;
int err;
err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
I2C_SMBUS_WORD_DATA, &data);
if (err < 0)
return err;
return data.word;
}
int set_slave_addr(int file, int address, int force)
{
/* With force, let the user read from/write to the registers
even when a driver is also running */
if (ioctl(file, force ? I2C_SLAVE_FORCE : I2C_SLAVE, address) < 0) {
fprintf(stderr,
"Error: Could not set address to 0x%02x: %s\n",
address, strerror(errno));
return -errno;
}
return 0;
}