distribution/packages/sysutils/system-utils/sources/scripts/headphone_sense

#!/bin/bash

# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2020-present Shanti Gilbert (https://github.com/shantigilbert)

# Source predefined functions and variables
. /etc/profile

# Switch to headphones if we have them already connected at boot
GPIO=$(cat /sys/class/gpio/gpio${DEVICE_JACK}/value)
[[ "$GPIO" == "0" ]] && set_setting "audio.device" "headphone" || set_setting "audio.device" "speakers"

if [ -e "/storage/.config/system/configs/system.cfg" ]; then
/usr/bin/system_utils setaudio $(get_setting "audio.device")
/usr/bin/system_utils vol $(get_setting "audio.volume")
fi

# Headphone sensing 
DEVICE="${DEVICE_HEADPHONE_DEV}"

HP_ON='*(SW_HEADPHONE_INSERT), value 0*'
HP_OFF='*(SW_HEADPHONE_INSERT), value 1*'

evtest "${DEVICE}" | while read line; do
    case $line in
	(${HP_ON})
	amixer -M cset name='Playback Path' HP
	set_setting "audio.device" "headphone"
	;;
	(${HP_OFF})
	amixer -M cset name='Playback Path' SPK
	set_setting "audio.device" "speakers"
	;;
    esac
done