Dockerfile

FROM balenalib/armv7hf-debian:buster AS kernel-builder

RUN apt-get update && apt-get install -y \
    build-essential \
    i2c-tools \
    wget \
    alsa-utils \
    && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

ARG HEADERS_URL="https://files.balena-cloud.com/images/raspberrypi3/2.47.0%2Brev1.prod/kernel_modules_headers.tar.gz"
ARG HEADERS_PATH=/tmp/kernel_modules_headers
ARG MODULE_URL="https://github.com/respeaker/seeed-voicecard/archive/master.tar.gz"
ARG MODULE_PATH="/opt/seeed-voicecard"

RUN mkdir -p $HEADERS_PATH \
    && cd $HEADERS_PATH \
    && wget $HEADERS_URL \
    && tar -xf kernel_modules_headers.tar.gz --strip 1
RUN mkdir -p $MODULE_PATH \
    && cd $MODULE_PATH \
    && wget $MODULE_URL \
    && tar -xf master.tar.gz --strip 1 \
    && make -C $HEADERS_PATH M=$MODULE_PATH modules \
    && mkdir -p /etc/voicecard \
    && cp *.conf /etc/voicecard \
    && cp *.state /etc/voicecard \
    && cp seeed-voicecard /usr/bin

##################################################

FROM balenalib/raspberrypi3-alpine:latest

RUN apk --no-cache add alsa-utils
RUN apk --no-cache --repository http://dl-cdn.alpinelinux.org/alpine/edge/community add i2c-tools mpv

RUN mkdir -p /app/modules \
    && mkdir -p /etc/voicecard

COPY --from=kernel-builder /opt/seeed-voicecard/*.ko /app/modules/
COPY --from=kernel-builder /opt/seeed-voicecard/*.dtbo /etc/voicecard/
COPY --from=kernel-builder /opt/seeed-voicecard/*.dts /etc/voicecard/
COPY --from=kernel-builder /opt/seeed-voicecard/*.conf /etc/voicecard/
COPY --from=kernel-builder /opt/seeed-voicecard/*.state /etc/voicecard/

WORKDIR /app
COPY run.sh .

CMD [ "/app/run.sh" ]

run.sh

#!/bin/bash

#enable i2c interface
modprobe i2c-dev
sleep 1

mod_dir="/app/modules"

modprobe snd-soc-simple-card-utils
insmod $mod_dir/snd-soc-seeed-voicecard.ko
insmod $mod_dir/snd-soc-ac108.ko
insmod $mod_dir/snd-soc-wm8960.ko

sleep 1

hw=$(aplay -l | grep seeed2micvoicec | awk '{print $2}' | sed 's/://')

cp /etc/voicecard/asound_2mic.conf /etc/asound.conf
cp /etc/voicecard/wm8960_asound.state /var/lib/alsa/asound.state

echo "Update ALSA config"
old=$(cat /etc/asound.conf | grep hw: | awk 'NR==1 {print $2}' | sed 's/\"//g')
sed -i -e "s/${old}/hw:${hw},0/g" /etc/asound.conf

alsactl restore

#Fore 3.5mm ('headphone') jack
amixer cset numid=3 1 

while :; do sleep 10; done