mfd: dt-bindings: Add RK805 device tree bindings document

Add device tree bindings documentation for Rockchip's RK805 PMIC.

Signed-off-by: Elaine Zhang <[e-mail]>
Signed-off-by: Joseph Chen <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Heiko Stuebner <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

Documentation/devicetree/bindings/mfd/rk808.txt

···
 RK8XX Power Management Integrated Circuit
 
 The rk8xx family current members:
+rk805
 rk808
 rk818
 
 Required properties:
-- compatible: "rockchip,rk808", "rockchip,rk818"
+- compatible: "rockchip,rk805"
+- compatible: "rockchip,rk808"
+- compatible: "rockchip,rk818"
 - reg: I2C slave address
 - interrupt-parent: The parent interrupt controller.
 - interrupts: the interrupt outputs of the controller.
···
   default output clock name
 - rockchip,system-power-controller: Telling whether or not this pmic is controlling
   the system power.
+
+Optional RK805 properties:
+- vcc1-supply:  The input supply for DCDC_REG1
+- vcc2-supply:  The input supply for DCDC_REG2
+- vcc3-supply:  The input supply for DCDC_REG3
+- vcc4-supply:  The input supply for DCDC_REG4
+- vcc5-supply:  The input supply for LDO_REG1 and LDO_REG2
+- vcc6-supply:  The input supply for LDO_REG3
 
 Optional RK808 properties:
 - vcc1-supply:  The input supply for DCDC_REG1
···
 	regulator-name {
 		/* standard regulator bindings here */
 	};
+
+Following regulators of the RK805 PMIC regulators are supported. Note that
+the 'n' in regulator name, as in DCDC_REGn or LDOn, represents the DCDC or LDO
+number as described in RK805 datasheet.
+
+	- DCDC_REGn
+		- valid values for n are 1 to 4.
+	- LDO_REGn
+		- valid values for n are 1 to 3
 
 Following regulators of the RK808 PMIC block are supported. Note that
 the 'n' in regulator name, as in DCDC_REGn or LDOn, represents the DCDC or LDO