How to add bluetooth reset gpio control to rfkill?

Try to use a DTS file to add  bluetooth reset gpio control to rfkill, but `rfkill list` doesn't show "sunxi-bt".

/dts-v1/;
/plugin/;

/ {
    compatible = "allwinner,sun8i-h3";

    fragment@0 {
        target = <&pio>;
        __overlay__ {
            bt_pwr_pin: bt_pwr_pin@0 {
                pins = "PG13";
                function = "gpio_out";
            };
        };
    };

    fragment@1 {
        target-path = "/";
        __overlay__ {
            rfkill_bt {
                compatible = "rfkill-gpio";
                pinctrl-names = "default";
                pinctrl-0 = <&bt_pwr_pin>;
                reset-gpios = <&pio 6 13 1>;
                clocks = <&osc32k>;
                clock-frequency = <32768>;
                rfkill-name = "sunxi-bt";
                rfkill-type = "bluetooth";
            };
        };
    };
};

Background:

Try to enable bluetooth on Nanopi Neo Air. After a lot of search, get bluetooth work finally. A few details are:

1. enable UART3 and its CTS & DTS. In /boot/armbianEnv.txt, add something like:

param_uart3_rtscts=1
overlays=uart3

2. control bluetooth reset pin PG13

3. enable RTC LOSC output

I use a script to test:

#!/bin/sh

# sudo apt install sunxi-tools devmem2

echo 'Enable 32K RTC LOSC output'
devmem2 0x1f00060 b 1 
echo 'reset bt'
sunxi-pio -m PG13=0 
sleep 1
sunxi-pio -m PG13=1
sleep 1
echo 'attach'
hciattach /dev/ttyS3 bcm43xx 1500000 flow bdaddr 11:22:33:44:55:66
echo 'config'
#hciconfig hci0 up

To setup RTC LOSC and PG13, we can also use the above DTS file.