[PATCH v3] ARM: OMAP3: PM: fix I/O wakeup and I/O chain clock control detection

Paul Walmsley [off-list ref] writes:

The way that we detect which OMAP3 chips support I/O wakeup and
software I/O chain clock control is broken.

Currently, I/O wakeup is marked as present for all OMAP3 SoCs other
than the AM3505/3517.  The TI81xx family of SoCs are at present
considered to be OMAP3 SoCs, but don't support I/O wakeup.  To resolve
this, convert the existing blacklist approach to an explicit,
whitelist support, in which only SoCs which are known to support I/O
wakeup are listed.  (At present, this only includes OMAP34xx,
OMAP3503, OMAP3515, OMAP3525, OMAP3530, and OMAP36xx.)

Also, the current code incorrectly detects the presence of a
software-controllable I/O chain clock on several chips that don't
support it.  This results in writes to reserved bitfields, unnecessary
delays, and console messages on kernels running on those chips:

    http://www.spinics.net/lists/linux-omap/msg58735.html

Convert this test to a feature test with a chip-by-chip whitelist.

Thanks to Dave Hylands [off-list ref] for reporting this problem
and doing some testing to help isolate the cause.  Thanks to Steve
Sakoman [off-list ref] for catching a bug in the first version of
this patch.

Based on the comments from Russell, I made a couple minor changes.
Here's the updated version (also in my for_3.1/pm-fixes-3 branch.)

Other than that, it looks like a good cleanup, queueing for v3.2 and
will submit to stable as well.

Tony, do you think we can still queue this as a fix for v3.1?

Kevin