Define gpio in device tree - linux-kernel

Question

I have a Ti's AM335x custom board. I want to define some pins as gpios and be able to set them as input and output in its Linux userspace.
I defined pins in am33xx_pinmux and then referenced it with the bone-pinmux-helper. The problem is I can set it with these commands on the terminal but it doesn't work.
echo 4 > /sys/class/gpios/export
echo out > /sys/class/gpios/gpio4/direction
echo 1 > /sys/class/gpios/value
here is a brief of my code for just two pins gpio0_4 gpio0_5, each pin must become available to set as input or output in userspace.
#include "am33xx.dtsi"
#include <dt-bindings/interrupt-controller/irq.h>
&am33xx_pinmux {
pinctrl-names = "default";
DATA_OUT_A00:DATA_OUT_A00 {
pinctrl-single,pins = <0x158 (PIN_OUTPUT_PULLDOWN | MUX_MODE7) >; /*gpio0_4*/
};
DATA_OUT_A01:DATA_OUT_A01 {
pinctrl-single,pins = <0x15C (PIN_OUTPUT_PULLDOWN | MUX_MODE7) >; /*gpio0_5*/
};
...
}
...
&ocp {
test_helper: helper {
compatible = "bone-pinmux-helper";
status = "okay";
pinctrl-names = "DATA_OUT_A00", "DATA_OUT_A01";
pinctrl-0 = <&DATA_OUT_A00>;
pinctrl-1 = <&DATA_OUT_A01>;
}
}
EDIT:-------------------
I'm using main Ti kernel 4.9 version. If I want to define these two pins as output this DTS works fine but ONLY for output mode. I can export pins as input but when I read its value it always returns zero.
#include "am33xx.dtsi"
#include <dt-bindings/interrupt-controller/irq.h>
/ {
model = "My Custom board C335x";
compatible = "ti,am33xx";
cpus {
cpu#0 {
cpu0-supply = <&vdd_core>;
};
};
...
gpio-leds {
compatible = "gpio-leds";
pinctrl-names = "default";
pinctrl-0 = <&led_pins>;
// the following two blocks make the pins available in /sys/class/leds
// if removed can be accessd with /sys/class/gpios
test_led1 {
label = "test";
gpios = <&gpio0 4 GPIO_ACTIVE_HIGH>;
default-state = "off";
};
test_led2 {
label = "test";
gpios = <&gpio0 4 GPIO_ACTIVE_HIGH>;
default-state = "off";
};
};
}
&am33xx_pinmux {
pinctrl-names = "default";
led_pins: pinmux_led_pins {
pinctrl-single,pins = <
0x158 (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /*gpio0_4*/
0x15C (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /*gpio0_5*/
>;
};
...
}
If I leave these pins in the DTS file, I still can export them but I can't get any input or set a value as output to them.