regulator: Add mode mapping function to struct regulator_desc

The "regulator-initial-mode" and "regulator-mode" DT properties allows
to configure the regulator operating modes at startup or when a system
enters into a susend state.

But these properties use as valid values the operating modes supported
by each device while the core deals with the standard operating modes.
So a mapping function is needed to translate from the hardware specific
modes to the standard ones.

This mapping is a non-varying configuration for each regulator, so add
a function pointer to struct regulator_desc that will allow drivers to
define their callback to do the modes translation.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/linux/regulator/driver.h

@@ -243,6 +243,8 @@ enum regulator_type {
  *
  * @enable_time: Time taken for initial enable of regulator (in uS).
  * @off_on_delay: guard time (in uS), before re-enabling a regulator
+ *
+ * @of_map_mode: Maps a hardware mode defined in a DeviceTree to a standard mode
  */
 struct regulator_desc {
 	const char *name;
@@ -285,6 +287,8 @@ struct regulator_desc {
 	unsigned int enable_time;
 
 	unsigned int off_on_delay;
+
+	unsigned int (*of_map_mode)(unsigned int mode);
 };
 
 /**