On Tue, Jan 15, 2019 at 09:42:09PM +0100, Takashi Iwai wrote:

> The last one has prepare and complete callbacks in addition to the
> other standard PM calls.  And tm2_pm_preapre() stops sysclk and
> complete() starts sysclk.  I don't understand why these are needed in
> prepare and resume.  Can anyone explain?

AFAICT it's just making sure that they're available ASAP so they look
always on to the rest of the system.