regulator: adapt fixed regulator driver to dt

The fixed regulator driver uses of_get_fixed_voltage_config()
to extract fixed_voltage_config structure contents from device tree.

Also add documenation for additional bindings for fixed
regulators that can be passed through dt.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/Documentation/devicetree/bindings/regulator/fixed-regulator.txt b/Documentation/devicetree/bindings/regulator/fixed-regulator.txt
new file mode 100644
index 0000000..9cf57fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/fixed-regulator.txt
@@ -0,0 +1,29 @@
+Fixed Voltage regulators
+
+Required properties:
+- compatible: Must be "regulator-fixed";
+
+Optional properties:
+- gpio: gpio to use for enable control
+- startup-delay-us: startup time in microseconds
+- enable-active-high: Polarity of GPIO is Active high
+If this property is missing, the default assumed is Active low.
+
+Any property defined as part of the core regulator
+binding, defined in regulator.txt, can also be used.
+However a fixed voltage regulator is expected to have the
+regulator-min-microvolt and regulator-max-microvolt
+to be the same.
+
+Example:
+
+	abc: fixedregulator@0 {
+		compatible = "regulator-fixed";
+		regulator-name = "fixed-supply";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		gpio = <&gpio1 16 0>;
+		startup-delay-us = <70000>;
+		enable-active-high;
+		regulator-boot-on
+	};