dt-bindings: qcom_spmi: Document SAW support

Document the DT bindings for the SAW regulators.

The saw-leader is the only property that is configurable in DT.

The saw-slave property allows ganging (grouping) of
several regulators so that their outputs can be combined.

Signed-off-by: Ilia Lin <ilialin@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/qcom,spmi-regulator.txt

@@ -110,6 +110,11 @@ Qualcomm SPMI Regulators
 	Definition: Reference to regulator supplying the input pin, as
 		    described in the data sheet.
 
+- qcom,saw-reg:
+	Usage: optional
+	Value type: <phandle>
+	Description: Reference to syscon node defining the SAW registers.
+
 
 The regulator node houses sub-nodes for each regulator within the device. Each
 sub-node is identified using the node's name, with valid values listed for each
@@ -201,6 +206,17 @@ see regulator.txt - with additional custom properties described below:
 			2 = 0.55 uA
 			3 = 0.75 uA
 
+- qcom,saw-slave:
+	Usage: optional
+	Value type: <boo>
+	Description: SAW controlled gang slave. Will not be configured.
+
+- qcom,saw-leader:
+	Usage: optional
+	Value type: <boo>
+	Description: SAW controlled gang leader. Will be configured as
+		     SAW regulator.
+
 Example:
 
 	regulators {
@@ -221,3 +237,32 @@ Example:
 
 		....
 	};
+
+Example 2:
+
+	saw3: syscon@9A10000 {
+		compatible = "syscon";
+		reg = <0x9A10000 0x1000>;
+	};
+
+	...
+
+	spm-regulators {
+		compatible = "qcom,pm8994-regulators";
+		qcom,saw-reg = <&saw3>;
+		s8 {
+			qcom,saw-slave;
+		};
+		s9 {
+			qcom,saw-slave;
+		};
+		s10 {
+			qcom,saw-slave;
+		};
+		pm8994_s11_saw: s11 {
+			qcom,saw-leader;
+			regulator-always-on;
+			regulator-min-microvolt = <900000>;
+			regulator-max-microvolt = <1140000>;
+		};
+	};