diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index ff9e5f2..2437dbc 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -6,6 +6,7 @@ TARGETS += exec
 TARGETS += firmware
 TARGETS += ftrace
 TARGETS += futex
+TARGETS += gpio
 TARGETS += ipc
 TARGETS += kcmp
 TARGETS += lib
diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile
new file mode 100644
index 0000000..e1144ba
--- /dev/null
+++ b/tools/testing/selftests/gpio/Makefile
@@ -0,0 +1,23 @@
+
+TEST_PROGS := gpio-mockup.sh
+TEST_FILES := gpio-mockup-sysfs.sh $(BINARIES)
+BINARIES := gpio-mockup-chardev
+
+include ../lib.mk
+
+all: $(BINARIES)
+
+clean:
+	$(RM) $(BINARIES)
+
+CFLAGS += -O2 -g -std=gnu99 -Wall -I../../../../usr/include/
+LDLIBS += -lmount -I/usr/include/libmount
+
+$(BINARIES): ../../../gpio/gpio-utils.o ../../../../usr/include/linux/gpio.h
+
+../../../gpio/gpio-utils.o:
+	make ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) -C ../../../gpio
+
+../../../../usr/include/linux/gpio.h:
+	make -C ../../../.. headers_install
+
diff --git a/tools/testing/selftests/gpio/gpio-mockup-chardev.c b/tools/testing/selftests/gpio/gpio-mockup-chardev.c
new file mode 100644
index 0000000..1868db6
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup-chardev.c
@@ -0,0 +1,321 @@
+/*
+ * GPIO chardev test helper
+ *
+ * Copyright (C) 2016 Bamvor Jian Zhang
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <libmount.h>
+#include <err.h>
+#include <dirent.h>
+#include <linux/gpio.h>
+#include "../../../gpio/gpio-utils.h"
+
+#define CONSUMER	"gpio-selftest"
+#define	GC_NUM		10
+enum direction {
+	OUT,
+	IN
+};
+
+static int get_debugfs(char **path)
+{
+	struct libmnt_context *cxt;
+	struct libmnt_table *tb;
+	struct libmnt_iter *itr = NULL;
+	struct libmnt_fs *fs;
+	int found = 0;
+
+	cxt = mnt_new_context();
+	if (!cxt)
+		err(EXIT_FAILURE, "libmount context allocation failed");
+
+	itr = mnt_new_iter(MNT_ITER_FORWARD);
+	if (!itr)
+		err(EXIT_FAILURE, "failed to initialize libmount iterator");
+
+	if (mnt_context_get_mtab(cxt, &tb))
+		err(EXIT_FAILURE, "failed to read mtab");
+
+	while (mnt_table_next_fs(tb, itr, &fs) == 0) {
+		const char *type = mnt_fs_get_fstype(fs);
+
+		if (!strcmp(type, "debugfs")) {
+			found = 1;
+			break;
+		}
+	}
+	if (found)
+		asprintf(path, "%s/gpio", mnt_fs_get_target(fs));
+
+	mnt_free_iter(itr);
+	mnt_free_context(cxt);
+
+	if (!found)
+		return -1;
+
+	return 0;
+}
+
+static int gpio_debugfs_get(const char *consumer, int *dir, int *value)
+{
+	char *debugfs;
+	FILE *f;
+	char *line = NULL;
+	size_t len = 0;
+	char *cur;
+	int found = 0;
+
+	if (get_debugfs(&debugfs) != 0)
+		err(EXIT_FAILURE, "debugfs is not mounted");
+
+	f = fopen(debugfs, "r");
+	if (!f)
+		err(EXIT_FAILURE, "read from gpio debugfs failed");
+
+	/*
+	 * gpio-2   (                    |gpio-selftest               ) in  lo
+	 */
+	while (getline(&line, &len, f) != -1) {
+		cur = strstr(line, consumer);
+		if (cur == NULL)
+			continue;
+
+		cur = strchr(line, ')');
+		if (!cur)
+			continue;
+
+		cur += 2;
+		if (!strncmp(cur, "out", 3)) {
+			*dir = OUT;
+			cur += 4;
+		} else if (!strncmp(cur, "in", 2)) {
+			*dir = IN;
+			cur += 4;
+		}
+
+		if (!strncmp(cur, "hi", 2))
+			*value = 1;
+		else if (!strncmp(cur, "lo", 2))
+			*value = 0;
+
+		found = 1;
+		break;
+	}
+	free(debugfs);
+	fclose(f);
+	free(line);
+
+	if (!found)
+		return -1;
+
+	return 0;
+}
+
+static struct gpiochip_info *list_gpiochip(const char *gpiochip_name, int *ret)
+{
+	struct gpiochip_info *cinfo;
+	struct gpiochip_info *current;
+	const struct dirent *ent;
+	DIR *dp;
+	char *chrdev_name;
+	int fd;
+	int i = 0;
+
+	cinfo = calloc(sizeof(struct gpiochip_info) * 4, GC_NUM + 1);
+	if (!cinfo)
+		err(EXIT_FAILURE, "gpiochip_info allocation failed");
+
+	current = cinfo;
+	dp = opendir("/dev");
+	if (!dp) {
+		*ret = -errno;
+		goto error_out;
+	}
+
+	while (ent = readdir(dp), ent) {
+		if (check_prefix(ent->d_name, "gpiochip")) {
+			*ret = asprintf(&chrdev_name, "/dev/%s", ent->d_name);
+			if (*ret < 0)
+				goto error_out;
+
+			fd = open(chrdev_name, 0);
+			if (fd == -1) {
+				*ret = -errno;
+				fprintf(stderr, "Failed to open %s\n",
+					chrdev_name);
+				goto error_close_dir;
+			}
+			*ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, current);
+			if (*ret == -1) {
+				perror("Failed to issue CHIPINFO IOCTL\n");
+				goto error_close_dir;
+			}
+			close(fd);
+			if (strcmp(current->label, gpiochip_name) == 0
+			    || check_prefix(current->label, gpiochip_name)) {
+				*ret = 0;
+				current++;
+				i++;
+			}
+		}
+	}
+
+	if ((!*ret && i == 0) || *ret < 0) {
+		free(cinfo);
+		cinfo = NULL;
+	}
+	if (!*ret && i > 0) {
+		cinfo = realloc(cinfo, sizeof(struct gpiochip_info) * 4 * i);
+		*ret = i;
+	}
+
+error_close_dir:
+	closedir(dp);
+error_out:
+	if (*ret < 0)
+		err(EXIT_FAILURE, "list gpiochip failed: %s", strerror(*ret));
+
+	return cinfo;
+}
+
+int gpio_pin_test(struct gpiochip_info *cinfo, int line, int flag, int value)
+{
+	struct gpiohandle_data data;
+	unsigned int lines[] = { line };
+	int fd;
+	int debugfs_dir;
+	int debugfs_value;
+	int ret;
+
+	data.values[0] = value;
+	ret = gpio_request(cinfo->name, lines, 1, flag, &data, CONSUMER);
+	if (ret < 0)
+		goto fail_out;
+	else
+		fd = ret;
+
+	ret = gpio_debugfs_get(CONSUMER, &debugfs_dir, &debugfs_value);
+	if (ret) {
+		ret = -EINVAL;
+		goto fail_out;
+	}
+	if (flag & GPIOHANDLE_REQUEST_INPUT) {
+		if (debugfs_dir != IN) {
+			errno = -EINVAL;
+			ret = -errno;
+		}
+	} else if (flag & GPIOHANDLE_REQUEST_OUTPUT) {
+		if (flag & GPIOHANDLE_REQUEST_ACTIVE_LOW)
+			debugfs_value = !debugfs_value;
+
+		if (!(debugfs_dir == OUT && value == debugfs_value))
+			errno = -EINVAL;
+		ret = -errno;
+
+	}
+
+	gpio_release(fd);
+fail_out:
+	if (ret)
+		err(EXIT_FAILURE, "gpio<%s> line<%d> test flag<0x%x> value<%d>",
+		    cinfo->name, line, flag, value);
+
+	return ret;
+}
+
+void gpio_pin_tests(struct gpiochip_info *cinfo, unsigned int line)
+{
+	printf("line<%d>", line);
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_OUTPUT, 0);
+	printf(".");
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_OUTPUT, 1);
+	printf(".");
+	gpio_pin_test(cinfo, line,
+		      GPIOHANDLE_REQUEST_OUTPUT | GPIOHANDLE_REQUEST_ACTIVE_LOW,
+		      0);
+	printf(".");
+	gpio_pin_test(cinfo, line,
+		      GPIOHANDLE_REQUEST_OUTPUT | GPIOHANDLE_REQUEST_ACTIVE_LOW,
+		      1);
+	printf(".");
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_INPUT, 0);
+	printf(".");
+}
+
+/*
+ * ./gpio-mockup-chardev gpio_chip_name_prefix is_valid_gpio_chip
+ * Return 0 if successful or exit with EXIT_FAILURE if test failed.
+ * gpio_chip_name_prefix: The prefix of gpiochip you want to test. E.g.
+ *			  gpio-mockup
+ * is_valid_gpio_chip:	  Whether the gpio_chip is valid. 1 means valid,
+ *			  0 means invalid which could not be found by
+ *			  list_gpiochip.
+ */
+int main(int argc, char *argv[])
+{
+	char *prefix;
+	int valid;
+	struct gpiochip_info *cinfo;
+	struct gpiochip_info *current;
+	int i;
+	int ret;
+
+	if (argc < 3) {
+		printf("Usage: %s prefix is_valid", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	prefix = argv[1];
+	valid = strcmp(argv[2], "true") == 0 ? 1 : 0;
+
+	printf("Test gpiochip %s: ", prefix);
+	cinfo = list_gpiochip(prefix, &ret);
+	if (!cinfo) {
+		if (!valid && ret == 0) {
+			printf("Invalid test successful\n");
+			ret = 0;
+			goto out;
+		} else {
+			ret = -EINVAL;
+			goto out;
+		}
+	} else if (cinfo && !valid) {
+		ret = -EINVAL;
+		goto out;
+	}
+	current = cinfo;
+	for (i = 0; i < ret; i++) {
+		gpio_pin_tests(current, 0);
+		gpio_pin_tests(current, current->lines - 1);
+		gpio_pin_tests(current, random() % current->lines);
+		current++;
+	}
+	ret = 0;
+	printf("successful\n");
+
+out:
+	if (ret)
+		fprintf(stderr, "gpio<%s> test failed\n", prefix);
+
+	if (cinfo)
+		free(cinfo);
+
+	if (ret)
+		exit(EXIT_FAILURE);
+
+	return ret;
+}
diff --git a/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh b/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh
new file mode 100755
index 0000000..085d7a3
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh
@@ -0,0 +1,134 @@
+
+is_consistent()
+{
+	val=
+
+	active_low_sysfs=`cat $GPIO_SYSFS/gpio$nr/active_low`
+	val_sysfs=`cat $GPIO_SYSFS/gpio$nr/value`
+	dir_sysfs=`cat $GPIO_SYSFS/gpio$nr/direction`
+
+	gpio_this_debugfs=`cat $GPIO_DEBUGFS |grep "gpio-$nr" | sed "s/(.*)//g"`
+	dir_debugfs=`echo $gpio_this_debugfs | awk '{print $2}'`
+	val_debugfs=`echo $gpio_this_debugfs | awk '{print $3}'`
+	if [ $val_debugfs = "lo" ]; then
+		val=0
+	elif [ $val_debugfs = "hi" ]; then
+		val=1
+	fi
+
+	if [ $active_low_sysfs = "1" ]; then
+		if [ $val = "0" ]; then
+			val="1"
+		else
+			val="0"
+		fi
+	fi
+
+	if [ $val_sysfs = $val ] && [ $dir_sysfs = $dir_debugfs ]; then
+		echo -n "."
+	else
+		echo "test fail, exit"
+		die
+	fi
+}
+
+test_pin_logic()
+{
+	nr=$1
+	direction=$2
+	active_low=$3
+	value=$4
+
+	echo $direction > $GPIO_SYSFS/gpio$nr/direction
+	echo $active_low > $GPIO_SYSFS/gpio$nr/active_low
+	if [ $direction = "out" ]; then
+		echo $value > $GPIO_SYSFS/gpio$nr/value
+	fi
+	is_consistent $nr
+}
+
+test_one_pin()
+{
+	nr=$1
+
+	echo -n "test pin<$nr>"
+
+	echo $nr > $GPIO_SYSFS/export 2>/dev/null
+
+	if [ X$? != X0 ]; then
+		echo "test GPIO pin $nr failed"
+		die
+	fi
+
+	#"Checking if the sysfs is consistent with debugfs: "
+	is_consistent $nr
+
+	#"Checking the logic of active_low: "
+	test_pin_logic $nr out 1 1
+	test_pin_logic $nr out 1 0
+	test_pin_logic $nr out 0 1
+	test_pin_logic $nr out 0 0
+
+	#"Checking the logic of direction: "
+	test_pin_logic $nr in 1 1
+	test_pin_logic $nr out 1 0
+	test_pin_logic $nr low 0 1
+	test_pin_logic $nr high 0 0
+
+	echo $nr > $GPIO_SYSFS/unexport
+
+	echo "successful"
+}
+
+test_one_pin_fail()
+{
+	nr=$1
+
+	echo $nr > $GPIO_SYSFS/export 2>/dev/null
+
+	if [ X$? != X0 ]; then
+		echo "test invalid pin $nr successful"
+	else
+		echo "test invalid pin $nr failed"
+		echo $nr > $GPIO_SYSFS/unexport 2>/dev/null
+		die
+	fi
+}
+
+list_chip()
+{
+	echo `ls -d $GPIO_DRV_SYSFS/gpiochip* 2>/dev/null`
+}
+
+test_chip()
+{
+	chip=$1
+	name=`basename $chip`
+	base=`cat $chip/base`
+	ngpio=`cat $chip/ngpio`
+	printf "%-10s %-5s %-5s\n" $name $base $ngpio
+	if [ $ngpio = "0" ]; then
+		echo "number of gpio is zero is not allowed".
+	fi
+	test_one_pin $base
+	test_one_pin $(($base + $ngpio - 1))
+	test_one_pin $((( RANDOM % $ngpio )  + $base ))
+}
+
+test_chips_sysfs()
+{
+       gpiochip=`list_chip $module`
+       if [ X"$gpiochip" = X ]; then
+               if [ X"$valid" = Xfalse ]; then
+                       echo "successful"
+               else
+                       echo "fail"
+                       die
+               fi
+       else
+               for chip in $gpiochip; do
+                       test_chip $chip
+               done
+       fi
+}
+
diff --git a/tools/testing/selftests/gpio/gpio-mockup.sh b/tools/testing/selftests/gpio/gpio-mockup.sh
new file mode 100755
index 0000000..256b094
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup.sh
@@ -0,0 +1,200 @@
+#!/bin/bash
+
+#exit status
+#1: run as non-root user
+#2: sysfs/debugfs not mount
+#3: insert module fail when gpio-mockup is a module.
+#4: other reason.
+
+SYSFS=
+GPIO_SYSFS=
+GPIO_DRV_SYSFS=
+DEBUGFS=
+GPIO_DEBUGFS=
+dev_type=
+module=
+
+usage()
+{
+	echo "Usage:"
+	echo "$0 [-f] [-m name] [-t type]"
+	echo "-f:  full test. It maybe conflict with existence gpio device."
+	echo "-m:  module name, default name is gpio-mockup. It could also test"
+	echo "     other gpio device."
+	echo "-t:  interface type: sysfs or chardev(char device). The latter"
+	echo "     one is default"
+	echo ""
+	echo "$0 -h"
+	echo "This usage"
+}
+
+prerequisite()
+{
+	msg="skip all tests:"
+	if [ $UID != 0 ]; then
+		echo $msg must be run as root >&2
+		exit 1
+	fi
+	SYSFS=`mount -t sysfs | head -1 | awk '{ print $3 }'`
+	if [ ! -d "$SYSFS" ]; then
+		echo $msg sysfs is not mounted >&2
+		exit 2
+	fi
+	GPIO_SYSFS=`echo $SYSFS/class/gpio`
+	GPIO_DRV_SYSFS=`echo $SYSFS/devices/platform/$module/gpio`
+	DEBUGFS=`mount -t debugfs | head -1 | awk '{ print $3 }'`
+	if [ ! -d "$DEBUGFS" ]; then
+		echo $msg debugfs is not mounted >&2
+		exit 2
+	fi
+	GPIO_DEBUGFS=`echo $DEBUGFS/gpio`
+	source gpio-mockup-sysfs.sh
+}
+
+try_insert_module()
+{
+	if [ -d "$GPIO_DRV_SYSFS" ]; then
+		echo "$GPIO_DRV_SYSFS exist. Skip insert module"
+	else
+		modprobe -q $module $1
+		if [ X$? != X0 ]; then
+			echo $msg insmod $module failed >&2
+			exit 3
+		fi
+	fi
+}
+
+remove_module()
+{
+	modprobe -r -q $module
+}
+
+die()
+{
+	remove_module
+	exit 4
+}
+
+test_chips()
+{
+	if [ X$dev_type = Xsysfs ]; then
+		test_chips_sysfs $*
+	else
+		$BASE/gpio-mockup-chardev $*
+	fi
+}
+
+gpio_test()
+{
+	param=$1
+	valid=$2
+
+	if [ X"$param" = X ]; then
+		die
+	fi
+	try_insert_module "gpio_mockup_ranges=$param"
+	echo -n "GPIO $module test with ranges: <"
+	echo "$param>: "
+	printf "%-10s %s\n" $param
+	test_chips $module $valid
+	remove_module
+}
+
+BASE=`dirname $0`
+
+dev_type=
+TEMP=`getopt -o fhm:t: -n '$0' -- "$@"`
+
+if [ "$?" != "0" ]; then
+        echo "Parameter process failed, Terminating..." >&2
+        exit 1
+fi
+
+# Note the quotes around `$TEMP': they are essential!
+eval set -- "$TEMP"
+
+while true; do
+	case $1 in
+	-f)
+		full_test=true
+		shift
+		;;
+	-h)
+		usage
+		exit
+		;;
+	-m)
+		module=$2
+		shift 2
+		;;
+	-t)
+		dev_type=$2
+		shift 2
+		;;
+	--)
+		shift
+		break
+		;;
+	*)
+		echo "Internal error!"
+		exit 1
+		;;
+	esac
+done
+
+if [ X"$module" = X ]; then
+	module="gpio-mockup"
+fi
+
+if [ X$dev_type != Xsysfs ]; then
+	dev_type="chardev"
+fi
+
+prerequisite
+
+echo "1.  Test dynamic allocation of gpio successful means insert gpiochip and"
+echo "    manipulate gpio pin successful"
+gpio_test "-1,32" true
+gpio_test "-1,32,-1,32" true
+gpio_test "-1,32,-1,32,-1,32" true
+if [ X$full_test = Xtrue ]; then
+	gpio_test "-1,32,32,64" true
+	gpio_test "-1,32,40,64,-1,5" true
+	gpio_test "-1,32,32,64,-1,32" true
+	gpio_test "0,32,32,64,-1,32,-1,32" true
+	gpio_test "-1,32,-1,32,0,32,32,64" true
+	echo "2.  Do basic test: successful means insert gpiochip and"
+	echo "    manipulate gpio pin successful"
+	gpio_test "0,32" true
+	gpio_test "0,32,32,64" true
+	gpio_test "0,32,40,64,64,96" true
+fi
+echo "3.  Error test: successful means insert gpiochip failed"
+echo "3.1 Test number of gpio overflow"
+#Currently: The max number of gpio(1024) is defined in arm architecture.
+gpio_test "-1,32,-1,1024" false
+if [ X$full_test = Xtrue ]; then
+	echo "3.2 Test zero line of gpio"
+	gpio_test "0,0" false
+	echo "3.3 Test range overlap"
+	echo "3.3.1 Test corner case"
+	gpio_test "0,32,0,1" false
+	gpio_test "0,32,32,64,32,40" false
+	gpio_test "0,32,35,64,35,45" false
+	gpio_test "0,32,31,32" false
+	gpio_test "0,32,32,64,36,37" false
+	gpio_test "0,32,35,64,34,36" false
+	echo "3.3.2 Test inserting invalid second gpiochip"
+	gpio_test "0,32,30,35" false
+	gpio_test "0,32,1,5" false
+	gpio_test "10,32,9,14" false
+	gpio_test "10,32,30,35" false
+	echo "3.3.3 Test others"
+	gpio_test "0,32,40,56,39,45" false
+	gpio_test "0,32,40,56,30,33" false
+	gpio_test "0,32,40,56,30,41" false
+	gpio_test "0,32,40,56,20,21" false
+fi
+
+echo GPIO test PASS
+
