[PATCH 1/4] devicetree: add a binding for a regulator that constrains its supply

[Alban Bedel <alban.bedel@avionic-design.de>]

Signed-off-by: Alban Bedel <alban.bedel@avionic-design.de>
---
 .../bindings/regulator/constrained-supply.txt      | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/regulator/constrained-supply.txt

diff --git a/Documentation/devicetree/bindings/regulator/constrained-supply.txt b/Documentation/devicetree/bindings/regulator/constrained-supply.txt
new file mode 100644
index 0000000..3c85430
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/constrained-supply.txt
@@ -0,0 +1,29 @@
+Constrained Supply Regulator
+
+This binding allow creating a virtual regulator that constrain its
+supply to provides the requested voltage. This is to allow using
+simple drivers that don't explicitly request a voltage on boards
+that have adjustable hardware regulators.
+
+Required properties:
+- compatible : Must be "regulator-constrained-supply".
+- vin-supply : phandle to the parent supply/regulator node
+
+Optional properties:
+- any property defined in regulator.txt
+
+Example:
+
+  /* Adjustable regulator for extension boards */
+  vdd_ext: regulator@0 {
+  	regulator-min-microvolt = <1000000>;
+  	regulator-max-microvolt = <10000000>;
+  };
+
+  /* An extension board that need 3.3V */
+  vdd_ext_board1: regulator@1 {
+	compatible = "regulator-constrained-supply";
+  	regulator-min-microvolt = <3300000>;
+  	regulator-max-microvolt = <3300000>;
+	vin-supply = <&vdd_ext>;
+  };
-- 
2.1.3