Hi,

this patch set reworks the mmp-sspa driver to work on a device
tree based MMP2 machines. My motivation is to make sound work on
a MMP2-based OLPC XO-1.75 laptop.

Note that currently the driver is pretty much orphaned -- it is not used by
any boards and nothing in tree provides the necessary clocks. This means
that risks of regressions are effectively zero; even though my test
configuration is not exhaustive and do not possess the datasheet.

I'm actually not convinced it would've worked too well if it was hooked
on (due to what patches 01/11, 02/11 and perhaps 09/11).

I've tested this on a XO-1.75 along with clk-audio driver that was
submitted separately ("MMP2 Audio clock controller driver" [1]),
mmp_tdma driver (with changes queued in linux-next), the rt5631 codec
and audio-graph-card.

[1] https://lore.kernel.org/lkml/20200511195534.1207927-1-lkundrak@v3.sk/ (local)

Thank you,
Lubo