[1] https://www.humblebazooka.com/2020/11/11/how-to-use-my-raspberry-pi-safe-shutdown-board/
[2] https://github.com/raspberrypi/firmware/blob/f145afcfdc76157622588d5c58b95da24acea1e8/boot/overlays/README#L1232
[3] https://github.com/raspberrypi/firmware/blob/f145afcfdc76157622588d5c58b95da24acea1e8/boot/overlays/README#L1199
[4] https://github.com/raspberrypi/linux/blob/rpi-5.10.y/arch/arm/boot/dts/overlays/gpio-shutdown-overlay.dts
[5] https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt
[6] https://github.com/raspberrypi/linux/blob/rpi-5.10.y/arch/arm/boot/dts/overlays/gpio-poweroff-overlay.dts
[7] https://github.com/EmuELEC/EmuELEC/blob/de6fdef7a78a79917018c73665494cb58cd09f61/projects/Amlogic-ce/devices/Amlogic-ng/bootloader/Radxa_Zero_boot.ini#L30
[8] https://github.com/home-assistant/operating-system/issues/1161
[9] https://github.com/home-assistant/operating-system/blob/2c3c066ea0264281b60295fca160b6ea8eda4ef1/buildroot-external/board/hardkernel/patches/linux/0008-arm64-dts-meson-g12b-add-power-button-support.patch
[10] https://github.com/EmuELEC/EmuELEC/blob/7d51b8e7105c9bad63c8866554071e16b72b08c0/projects/Amlogic/patches/u-boot/u-boot-0006-FROMGIT-ARM-meson-Sync-Amlogic-DT-from-Linux-5.14.patch#L491
[11] https://github.com/EmuELEC/EmuELEC/blob/7d51b8e7105c9bad63c8866554071e16b72b08c0/projects/Amlogic/devices/AMLGX/patches/linux/amlogic-0012-FROMGIT-arm64-dts-amlogic-add-support-for-Radxa-Zero.patch
[12] https://github.com/radxa/kernel/blob/linux-5.10.y-radxa-zero/arch/arm64/boot/dts/amlogic/meson-g12a-radxa-zero.dts
[13] https://github.com/radxa/kernel/blob/57a25a2f2f476f98a9a98115853b29f10b086f77/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts#L36