regulator: Add REGULATOR_STATUS_UNDEFINED.

REGULATOR_STATUS_UNDEFINED is to be returned by regulator, if any other state
doesn't really apply.

Signed-off-by: Krystian Garbaciak <krystian.garbaciak@diasemi.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 4b136f8..01a67c5 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -393,6 +393,9 @@
 	case REGULATOR_STATUS_STANDBY:
 		label = "standby";
 		break;
+	case REGULATOR_STATUS_UNDEFINED:
+		label = "undefined";
+		break;
 	default:
 		return -ERANGE;
 	}
@@ -2897,7 +2900,7 @@
 	case REGULATOR_MODE_STANDBY:
 		return REGULATOR_STATUS_STANDBY;
 	default:
-		return 0;
+		return REGULATOR_STATUS_UNDEFINED;
 	}
 }
 EXPORT_SYMBOL_GPL(regulator_mode_to_status);
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 8022638..2513a54 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -32,6 +32,8 @@
 	REGULATOR_STATUS_NORMAL,
 	REGULATOR_STATUS_IDLE,
 	REGULATOR_STATUS_STANDBY,
+	/* in case that any other status doesn't apply */
+	REGULATOR_STATUS_UNDEFINED,
 };
 
 /**