能给一个at24c256的C语言驱动代码吗？

当然可以，以下是一个基于I2C总线的AT24C256 EEPROM的C语言驱动代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>

#define I2C_BUS "/dev/i2c-1"
#define EEPROM_ADDR 0x50

int i2c_fd;

void i2c_init() {
    i2c_fd = open(I2C_BUS, O_RDWR);
    if (i2c_fd < 0) {
        perror("open i2c bus failed");
        exit(EXIT_FAILURE);
    }
}

void i2c_deinit() {
    close(i2c_fd);
}

int i2c_write(unsigned char *buf, int len) {
    if (write(i2c_fd, buf, len) != len) {
        perror("write i2c bus failed");
        return -1;
    }
    return 0;
}

int i2c_read(unsigned char *buf, int len) {
    if (read(i2c_fd, buf, len) != len) {
        perror("read i2c bus failed");
        return -1;
    }
    return 0;
}

void eeprom_write(unsigned short addr, unsigned char *buf, int len) {
    unsigned char write_buf[256];
    int i;
    write_buf[0] = addr >> 8;
    write_buf[1] = addr & 0xFF;
    for (i = 0; i < len; i++) {
        write_buf[i + 2] = buf[i];
    }
    i2c_write(write_buf, len + 2);
    usleep(10000); // 10ms delay
}

void eeprom_read(unsigned short addr, unsigned char *buf, int len) {
    unsigned char write_buf[2];
    write_buf[0] = addr >> 8;
    write_buf[1] = addr & 0xFF;
    i2c_write(write_buf, 2);
    i2c_read(buf, len);
}

int main() {
    unsigned char buf[256];
    unsigned short addr = 0x0000;
    int i;

    i2c_init();

    // write data to eeprom
    for (i = 0; i < 256; i++) {
        buf[i] = i;
    }
    eeprom_write(addr, buf, 256);

    // read data from eeprom
    for (i = 0; i < 256; i++) {
        buf[i] = 0;
    }
    eeprom_read(addr, buf, 256);
    for (i = 0; i < 256; i++) {
        printf("%02X ", buf[i]);
        if ((i + 1) % 16 == 0) {
            printf("\n");
        }
    }

    i2c_deinit();
    return 0;
}

这是一个基本的驱动程序框架，你可以根据具体的应用场景进行修改和优化。