bindings: mfd: s2mps11: Add documentation for s2mps15 PMIC

Add dt-binding documentation for s2mps15 PMIC device. The s2mps15 device
is similar to s2mps11/14 PMIC device and has 27 LDO and 10 buck regulators.
This also supports RTC and three 32.768KHz clock outputs.
Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/s2mps11.txt

 
-* Samsung S2MPS11, S2MPS13, S2MPS14 and S2MPU02 Voltage and Current Regulator
+* Samsung S2MPS11/13/14/15 and S2MPU02 Voltage and Current Regulator
 
 The Samsung S2MPS11 is a multi-function device which includes voltage and
 current regulators, RTC, charger controller and other sub-blocks. It is
@@ -7,8 +7,12 @@ interfaced to the host controller using an I2C interface. Each sub-block is
 addressed by the host system using different I2C slave addresses.
 
 Required properties:
-- compatible: Should be "samsung,s2mps11-pmic" or "samsung,s2mps13-pmic"
-	      or "samsung,s2mps14-pmic" or "samsung,s2mpu02-pmic".
+- compatible: Should be one of the following
+	- "samsung,s2mps11-pmic"
+	- "samsung,s2mps13-pmic"
+	- "samsung,s2mps14-pmic"
+	- "samsung,s2mps15-pmic"
+	- "samsung,s2mpu02-pmic".
 - reg: Specifies the I2C slave address of the pmic block. It should be 0x66.
 
 Optional properties:
@@ -20,7 +24,7 @@ Optional properties:
   unwanted buck warm reset (setting buck voltages to default values).
 
 Optional nodes:
-- clocks: s2mps11, s2mps13 and s5m8767 provide three(AP/CP/BT) buffered 32.768
+- clocks: s2mps11, s2mps13, s2mps15 and s5m8767 provide three(AP/CP/BT) buffered 32.768
   KHz outputs, so to register these as clocks with common clock framework
   instantiate a sub-node named "clocks". It uses the common clock binding
   documented in :
@@ -33,12 +37,13 @@ Optional nodes:
     the clock which they consume.
     Clock               ID           Devices
     ----------------------------------------------------------
-    32KhzAP		0            S2MPS11, S2MPS13, S2MPS14, S5M8767
-    32KhzCP		1            S2MPS11, S2MPS13, S5M8767
-    32KhzBT		2            S2MPS11, S2MPS13, S2MPS14, S5M8767
+    32KhzAP		0            S2MPS11, S2MPS13, S2MPS14, S2MPS15, S5M8767
+    32KhzCP		1            S2MPS11, S2MPS13, S2MPS15, S5M8767
+    32KhzBT		2            S2MPS11, S2MPS13, S2MPS14, S2MPS15, S5M8767
 
   - compatible: Should be one of: "samsung,s2mps11-clk", "samsung,s2mps13-clk",
 		"samsung,s2mps14-clk", "samsung,s5m8767-clk"
+    The s2msp15 uses the same compatible as s2mps13, as both provides similar clocks.
 
 - regulators: The regulators of s2mps11 that have to be instantiated should be
 included in a sub-node named 'regulators'. Regulator nodes included in this
@@ -86,6 +91,7 @@ as per the datasheet of s2mps11.
 			- S2MPS11: 1 to 38
 			- S2MPS13: 1 to 40
 			- S2MPS14: 1 to 25
+			- S2MPS15: 1 to 27
 			- S2MPU02: 1 to 28
 		  - Example: LDO1, LDO2, LDO28
 	- BUCKn
@@ -93,6 +99,7 @@ as per the datasheet of s2mps11.
 			- S2MPS11: 1 to 10
 			- S2MPS13: 1 to 10
 			- S2MPS14: 1 to 5
+			- S2MPS15: 1 to 10
 			- S2MPU02: 1 to 7
 		  - Example: BUCK1, BUCK2, BUCK9