diff -ruN iotools-1.5~/i2c_rw.c iotools-1.5/i2c_rw.c
--- iotools-1.5~/i2c_rw.c	1969-12-31 16:00:00.000000000 -0800
+++ iotools-1.5/i2c_rw.c	2017-03-16 09:52:49.386028184 -0700
@@ -0,0 +1,166 @@
+/*
+ Copyright 2017 Google Inc.
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include "commands.h"
+#include "linux-i2c-dev.h"
+
+#define I2C_MAX_LEN 32
+
+struct i2c_params {
+	uint8_t i2c_bus;
+	uint8_t address;
+	uint8_t read_len;
+	uint8_t write_len;
+	uint8_t read_data[I2C_MAX_LEN];
+	uint8_t write_data[I2C_MAX_LEN];
+};
+
+static int
+parse_uint8(const char *arg, uint8_t *ret)
+{
+	unsigned long ldata;
+	char *end;
+
+	ldata = strtoul(arg, &end, 0);
+	if (ldata == LONG_MAX || *end != '\0') {
+		return -1;
+	}
+	*ret = (uint8_t)ldata;
+	return 0;
+}
+
+static int
+i2c_params(int argc, const char *argv[], struct i2c_params *params)
+{
+	int len, arg = 1;
+
+	memset(params, 0, sizeof(struct i2c_params));
+
+	if (parse_uint8(argv[arg++], &params->i2c_bus)) {
+		fprintf(stderr, "invalid adapter value\n");
+		return -1;
+	}
+	if (parse_uint8(argv[arg++], &params->address)) {
+		fprintf(stderr, "invalid address value\n");
+		return -1;
+	}
+	if (parse_uint8(argv[arg++], &params->read_len)) {
+		fprintf(stderr, "invalid read length value\n");
+		return -1;
+	}
+	if (params->read_len > I2C_MAX_LEN) {
+		fprintf(stderr, "invalid read length value %d\n",
+			params->read_len);
+		return -1;
+	}
+
+	/* Data to write */
+	for (len = 0; arg < argc; arg++, len++) {
+		if (parse_uint8(argv[arg], &params->write_data[len])) {
+			fprintf(stderr, "error parsing write data %d", len);
+			return -1;
+		}
+	}
+	params->write_len = len;
+
+	return 0;
+}
+
+static int
+i2c_xfer(int argc, const char *argv[], const struct cmd_info *info)
+{
+	int i, ret = 0;
+	struct i2c_params params;
+	struct i2c_rdwr_ioctl_data data;
+	struct i2c_msg msg[2];
+	char devfile[15];
+	int fd;
+
+	if (i2c_params(argc, argv, &params) < 0)
+		return -1;
+
+	memset(msg, 0, sizeof(struct i2c_msg) * 2);
+	memset(&data, 0, sizeof(struct i2c_rdwr_ioctl_data));
+
+	if (params.write_len > 0) {
+		/* Write message */
+		msg[data.nmsgs].addr = params.address;
+		msg[data.nmsgs].flags = 0;
+		msg[data.nmsgs].len = params.write_len;
+		msg[data.nmsgs].buf = params.write_data;
+		data.nmsgs++;
+	}
+
+	if (params.read_len > 0) {
+		/* Read message */
+		msg[data.nmsgs].addr = params.address;
+		msg[data.nmsgs].flags = I2C_M_RD;
+		msg[data.nmsgs].len = params.read_len;
+		msg[data.nmsgs].buf = params.read_data;
+		data.nmsgs++;
+	}
+
+	data.msgs = msg;
+
+	/* Open slave device */
+	sprintf(devfile, "/dev/i2c-%d", params.i2c_bus);
+	fd = open(devfile, O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "Couldn't open i2c device file: %s\n",
+			strerror(errno));
+		return -1;
+	}
+
+	ret = ioctl(fd, I2C_RDWR, &data);
+	close(fd);
+
+	if (ret < 0 || ret != data.nmsgs) {
+		fprintf(stderr, "i2c transfer failed: %s\n",
+			strerror(errno));
+		ret = -1;
+	}
+
+	/* Print out the read data */
+	if (params.read_len > 0) {
+		for (i = 0; i < params.read_len; i++) {
+			printf("0x%02x ", params.read_data[i]);
+		}
+		printf("\n");
+	}
+
+	return ret;
+}
+
+MAKE_PREREQ_PARAMS_VAR_ARGS(i2c_xfer_params, 3, I2C_MAX_LEN + 3,
+	"<adapter> <address> <read_count> [write bytes...]", 0);
+
+static const struct cmd_info i2c_cmds[] = {
+	MAKE_CMD_WITH_PARAMS(i2c_xfer, &i2c_xfer, NULL, &i2c_xfer_params)
+};
+
+MAKE_CMD_GROUP(I2C, "commands to access I2C devices", i2c_cmds);
+REGISTER_CMD_GROUP(I2C);
diff -ruN iotools-1.5~/linux-i2c-dev.h iotools-1.5/linux-i2c-dev.h
--- iotools-1.5~/linux-i2c-dev.h	2013-04-23 10:01:37.000000000 -0700
+++ iotools-1.5/linux-i2c-dev.h	2017-03-16 09:33:43.519882173 -0700
@@ -38,17 +38,17 @@
  */
 struct i2c_msg {
 	__u16 addr;	/* slave address			*/
-	unsigned short flags;		
-#define I2C_M_TEN	0x10	/* we have a ten bit chip address	*/
-#define I2C_M_RD	0x01
-#define I2C_M_NOSTART	0x4000
-#define I2C_M_REV_DIR_ADDR	0x2000
-#define I2C_M_IGNORE_NAK	0x1000
-#define I2C_M_NO_RD_ACK		0x0800
-	short len;		/* msg length				*/
-	char *buf;		/* pointer to msg data			*/
-	int err;
-	short done;
+	__u16 flags;
+#define I2C_M_TEN		0x0010	/* this is a ten bit chip address */
+#define I2C_M_RD		0x0001	/* read data, from slave to master */
+#define I2C_M_STOP		0x8000	/* if I2C_FUNC_PROTOCOL_MANGLING */
+#define I2C_M_NOSTART		0x4000	/* if I2C_FUNC_NOSTART */
+#define I2C_M_REV_DIR_ADDR	0x2000	/* if I2C_FUNC_PROTOCOL_MANGLING */
+#define I2C_M_IGNORE_NAK	0x1000	/* if I2C_FUNC_PROTOCOL_MANGLING */
+#define I2C_M_NO_RD_ACK		0x0800	/* if I2C_FUNC_PROTOCOL_MANGLING */
+#define I2C_M_RECV_LEN		0x0400	/* length will be first received byte */
+	__u16 len;		/* msg length				*/
+	__u8 *buf;		/* pointer to msg data			*/
 };
 
 /* To determine what functionality is present */
@@ -191,7 +191,7 @@
 /* This is the structure as used in the I2C_RDWR ioctl call */
 struct i2c_rdwr_ioctl_data {
 	struct i2c_msg *msgs;	/* pointers to i2c_msgs */
-	int nmsgs;		/* number of i2c_msgs */
+	__u32 nmsgs;		/* number of i2c_msgs */
 };