regulator: axp20x: add drivevbus support for axp803

Like axp221, axp223, axp813 the axp803 is also supporting external
regulator to drive the  OTG VBus through N_VBUSEN PMIC pin.

Add support for it.
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/mfd/axp20x.txt

@@ -43,7 +43,7 @@ Optional properties:
 			  regulator to drive the OTG VBus, rather then
 			  as an input pin which signals whether the
 			  board is driving OTG VBus or not.
-			  (axp221 / axp223 / axp813 only)
+			  (axp221 / axp223 / axp803/ axp813 only)
 
 - x-powers,master-mode: Boolean (axp806 only). Set this when the PMIC is
 			wired for master mode. The default is slave mode.
@@ -132,6 +132,7 @@ FLDO2		: LDO		: fldoin-supply		: shared supply
 LDO_IO0		: LDO		: ips-supply		: GPIO 0
 LDO_IO1		: LDO		: ips-supply		: GPIO 1
 RTC_LDO		: LDO		: ips-supply		: always on
+DRIVEVBUS	: Enable output	: drivevbus-supply	: external regulator
 
 AXP806 regulators, type, and corresponding input supply names:
 

drivers/regulator/axp20x-regulator.c

@@ -721,6 +721,8 @@ static int axp20x_regulator_probe(struct platform_device *pdev)
 	case AXP803_ID:
 		regulators = axp803_regulators;
 		nregulators = AXP803_REG_ID_MAX;
+		drivevbus = of_property_read_bool(pdev->dev.parent->of_node,
+						  "x-powers,drive-vbus-en");
 		break;
 	case AXP806_ID:
 		regulators = axp806_regulators;