sunxi-a20 cubieboard drm fails to load with backlight node

[sayyed mohsen Zahraee]

i dont know what happen. if i enable backlight with following settings on cubieboard2

sun4i-drm  will fail to load  so if i remove enable-gpios from backlight and palace it in panel properties it will be okay

i think it is odd thing and should be possible BUG!

/ {

    panel: panel {
        compatible = "panel-lvds";
        pinctrl-names = "default";
        pinctrl-0 = <&lcd_lvds0_pins>;
        
        backlight = <&backlight>;
        power-supply = <&reg_vcc3v3>;
        #address-cells = <1>;
        #size-cells = <0>;

        port {
            lvds_panel_in: endpoint {
                remote-endpoint = <&display_out_rgb>;
            };
        };
    };

    backlight: backlight {
        compatible = "pwm-backlight";
        pwms = <&pwm 0 50000 0>;
                brightness-levels = <0 10 20 30 40 50 60 70 80 90 100>;
        enable-gpios = <&pio 7 7 GPIO_ACTIVE_HIGH>; /* PH7 */
        power-supply = <&reg_vcc3v3>;
    };

};

&pwm {

    pinctrl-names = "default";
    pinctrl-0 = <&pwm0_pin>;
    status = "okay";
};

&tcon0 {
    ports {
        tcon0_out: port@1 {
            display_out_rgb: endpoint@0 {
                reg = <0>;
                remote-endpoint = <&lvds_panel_in>;
                allwinner,tcon-channel = <0>;
            };
        };
    };
};