Phat beat pivumeter with mpd issue

Hi, i am using the phat beat with pi zero w and mpd as user pi. Everything works well except pivumeter.
I installed the suggested asound.conf from git repository.
Audio output in mpd.conf is as follows:
audio_output {
type "alsa"
name "Pivumeter Audio"
device "pivumeter"
mixer_type "software"
Sound output is ok. Vu meter doesn’t work.
At tests with omxplayer and shairport-sync sound and vu-meter are working without any changes to asound.conf.
Looking at the mpd log-file i found the following lines:
Using device: phat-beat
gpio: Must be root to run. Program should be suid root. This is an error.
gpio: Must be root to run. Program should be suid root. This is an error.
I added mpd to the groups audio and gpio but nothing changes.
Changing mpd to user root doesn’t help.
The lines in mpd log-file change to:
Using device: phat-beat
gpio: Unable to open GPIO export interface: Read-only file system
gpio: Unable to open GPIO export interface: Read-only file system
and vu meter is still not working.
Does anybody know what’s wrong with mpd and pivumeter?