Today i tried some other things and found out
$ /usr/sbin/i2cdetect -l
i2c-3 unknown rk3x-i2c N/A
i2c-1 unknown rk3x-i2c N/A
i2c-4 unknown rk3x-i2c N/A
i2c-0 unknown rk3x-i2c N/A
i2c-7 unknown rk3x-i2c N/A
that my i2c bus is not configured. For me it seems that overlay is not configured properly but i am a newbie to that topic.
Anyone an idea?