[alsa-devel] ASOC and 12 bit volume control

How do I define a volume control that is the bottom 12 bits of a 32 bit register?

#define SOC_SINGLE_VALUE(reg, shift, max, invert) ((reg) | ((shift) << 8) |\ ((shift) << 12) | ((max) << 16) | ((invert) << 24))

This looks like it only support an 8 bit max. Is there another way to do it?