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)
# Copyright (C) 2021-present Fewtarius

# 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"

### Set the default audio path, needed for some devices
if [ -z "${DEVICE_PLAYBACK_PATH}" ]
then
  DEVICE_PLAYBACK_PATH="Playback Path"
fi

STARTUP_DEVICE=$(get_setting "audio.device")
case "${2}" in
    "headphone")
        amixer -c 0 -M cset name=${DEVICE_PLAYBACK_PATH} ${DEVICE_PLAYBACK_PATH_HP}
    ;;
    "auto"|"speakers"|*)
        amixer -c 0 -M cset name=${DEVICE_PLAYBACK_PATH} ${DEVICE_PLAYBACK_PATH_SPK}
    ;;
esac

/usr/bin/volume $(get_setting "audio.volume")

# 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 -c 0 cset name=${DEVICE_PLAYBACK_PATH} ${DEVICE_PLAYBACK_PATH_HP}
	set_setting "audio.device" "headphone"
	;;
	(${HP_OFF})
	amixer -c 0 cset name=${DEVICE_PLAYBACK_PATH} ${DEVICE_PLAYBACK_PATH_SPK}
	set_setting "audio.device" "speakers"
	;;
    esac
done