Support logical units

[azat-io]

What do you think about adding support for logical units?

Physical Unit	Logical Unit
cqh	cqb
cqw	cqi
dvh	dvb
dvw	dvi
lvh	lvb
lvw	lvi
svh	svb
svw	svi
vh	vb
vw	vi

[romainmenke]

PR's are welcome!