regulator: twl4030 regulators

regulator: twl4030 regulators

Support most of the LDO regulators in the twl4030 family chips.
In the case of LDOs supporting MMC/SD, the voltage controls are
used; but in most other cases, the regulator framework is only
used to enable/disable a supplies, conserving power when a given
voltage rail is not needed.

The drivers/mfd/twl4030-core.c code already sets up the various
regulators according to board-specific configuration, and knows
that some chips don't provide the full set of voltage rails.

The omitted regulators are intended to be under hardware control,
such as during the hardware-mediated system powerup, powerdown,
and suspend states.  Unless/until software hooks are known to
be safe, they won't be exported here.

These regulators implement the new get_status() operation, but
can't realistically implement get_mode(); the status output is
effectively the result of a vote, with the relevant hardware
inputs not exposed.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>