cambridge audio dac magic 100 and mixer types ( no hardware)

Hello everyone I have a question,
I use hifiberry digi + pro and a dac cambridge audio dac magic 100 but from the volume settings I don’t see the hardware mode among the mixer types but only software or none.
what should I do?
thank you

The Hifiberry Digi+ does not have hardware volume control as I understand it (link).
However, Hifiberry themselves have made a comparison showing that there is no loss in using software volume control. See this article.