regulator_get_optional — obtain optional access to a regulator.
|struct device * dev,|
|const char * id|
Returns a struct regulator corresponding to the regulator producer,
IS_ERR condition containing errno.
This is intended for use by consumers for devices which can have
some supplies unconnected in normal use, such as some MMC devices.
It can allow the regulator core to provide stub supplies for other
supplies requested using normal
regulator_get calls without
disrupting the operation of drivers that can handle absent
Use of supply names configured via
strongly encouraged. It is recommended that the supply name used
should match the name used for the supply and/or the relevant
device pins in the datasheet.