Values such as max_brightness should be set before backlights are
registered, but the current API doesn't allow that. Add a parameter to
backlight_device_register and update drivers to ensure that they
set this correctly.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NRichard Purdie <rpurdie@linux.intel.com>

Signed-off-by: NEmese Revfy <re.emese@gmail.com>
Signed-off-by: NRichard Purdie <rpurdie@linux.intel.com>

The WM831x series of PMICs provide DC-DC boost convertors and current
sinks which can be used together to drive LEDs for use as backlights.
Expose this functionality via the backlight API.

Since when used in this configuration the current sink and boost
convertor are very tightly coupled with a multi-stage startup for
the current sink which overlaps with the boost convertor startup
this driver bypasses the regulator API. Machine inititialisation
is responsible for ensuring that the regulators are not accessed
via both APIs.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NRichard Purdie <rpurdie@linux.intel.com>