simple CLI tool to scan i2c devices

Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)

LOCAL_SRC_FILES += i2c_scan.c
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE := i2c_scan

include $(BUILD_EXECUTABLE)

i2c_scan.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#define I2C_RDWR    0x0707

struct i2c_msg {
	unsigned short addr;
	unsigned short flags;
	unsigned short len;
	unsigned char *buf;
};

struct i2c_rdwr_ioctl_data {
	struct i2c_msg *msgs;
	unsigned int nmsgs;
};

static int i2c_scan(int fd)
{
	int rc, adr, found = 0;
	struct i2c_msg msg;
	struct i2c_rdwr_ioctl_data msgset;

	/* scan the whole I²C bus range */
	for (adr = 1; adr < 128; adr++) {
		msg.addr = adr;
		msg.flags = 0;
		msg.buf = 0;
		msg.len = 0;

		msgset.msgs = &msg;
		msgset.nmsgs = 1;

		rc = ioctl(fd, I2C_RDWR, &msgset);
		if (rc == 1) {
			found++;
			printf("Find Device I2C Addr = 0x%02x \n", adr);
		}
	}

	return 0;
}

int main(int argc, char *argv[])
{
	int j;
	int n, i;
	int iret = 0;
	int chip;
	unsigned char value = 0x00;

	if (argc != 2) {
		printf("Usage: %s [i2c_ch_num]\n", argv[0]);
		exit(1);
	}

	char i2c_dev_path[15];
	sprintf(i2c_dev_path, "/dev/i2c-%s", argv[1]);
	printf("Scanning %s...\n", i2c_dev_path);

	int fd = open(i2c_dev_path, O_RDWR);
	if (fd < 0) {
		printf("Open Error...!\n");
		exit(1);
	}

	i2c_scan(fd);
	close(fd);

	return 0;
}

thank you~