dump I2C EEPROM memory from Linux device ioctl

dump_i2c_eeprom.c

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>

#include <linux/i2c-dev.h>


#define READ_SIZE	(256)
#define NB_PAGES	(256)


/* UTILS **********************************************************************/
void hexprint(const uint8_t *input, const int input_length)
{
	int i = 0;

	for (i = 0; i < input_length; i++) {
		if (i%16 == 0) {
			printf("\n");
		}
		printf("%02x ", input[i]);
	}
	printf("\n");
}

void dump_to_file(const char *output_file_path,
		  const uint8_t *buffer, const int buffer_length)
{
	int output_file = open(output_file_path, O_RDWR|O_APPEND|O_CREAT);
	if (output_file < 0) {
		printf("Failed opening output file %s\n", output_file_path);
		return;
	}

	write(output_file, buffer, buffer_length);
}


/* MAIN ***********************************************************************/
int main(int argc, char *argv[])
{
	/* got these values from i2cdetect */
	const char *i2c_device = "/dev/i2c-2";
	const int device_address = 0x50;

	/* open the i2c device file */
	int file = open(i2c_device, O_RDWR);
	if (file < 0) {
		printf("Failed opening %s\n", i2c_device);
		return 1;
	}

	if (ioctl(file, I2C_SLAVE, device_address) < 0) {
		printf("Failed addressing device at %02X\n", device_address);
		close(file);
		return 1;
	}

	int i = 0;
	for (i = 0; i < NB_PAGES; i++) {
		char buf[READ_SIZE] = {0};

		if (read(file, buf, READ_SIZE) != READ_SIZE) {
			printf("Failed reading\n");
			close(file);
			return 1;
		}

		//hexprint(buf, READ_SIZE);
		dump_to_file(argv[1], buf, READ_SIZE);
	}

	close(file);

	return 0;
}

here is the full backup and restore program which now includes also the "aknowledge polling" (before I had just an ugly usleep function).

https://gist.github.com/Zibri/cf8ac0b311301aeeaa8910c7da824bff