regulator: helper routine to extract regulator_init_data

The helper routine is meant to be used by the regulator drivers
to extract the regulator_init_data structure from the data
that is passed from device tree.
'consumer_supplies' which is part of regulator_init_data is not extracted
as the regulator consumer mappings are passed through DT differently,
implemented in subsequent patches.
Similarly the regulator<-->parent/supply mapping is handled in
subsequent patches.

Also add documentation for regulator bindings to be used to pass
regulator_init_data struct information from device tree.

Some of the regulator properties which are linux and board specific,
are left out since its not clear if they can
be in someway embedded into the kernel or passed in from DT.
They will be revisited later.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt
new file mode 100644
index 00000000000..82bef20d4c4
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/regulator.txt
@@ -0,0 +1,54 @@
+Voltage/Current Regulators
+
+Optional properties:
+- regulator-name: A string used as a descriptive name for regulator outputs
+- regulator-min-microvolt: smallest voltage consumers may set
+- regulator-max-microvolt: largest voltage consumers may set
+- regulator-microvolt-offset: Offset applied to voltages to compensate for voltage drops
+- regulator-min-microamp: smallest current consumers may set
+- regulator-max-microamp: largest current consumers may set
+- regulator-always-on: boolean, regulator should never be disabled
+- regulator-boot-on: bootloader/firmware enabled regulator
+- <name>-supply: phandle to the parent supply/regulator node
+
+Example:
+
+        xyzreg: regulator@0 {
+                regulator-min-microvolt = <1000000>;
+                regulator-max-microvolt = <2500000>;
+                regulator-always-on;
+                vin-supply = <&vin>;
+        };
+
+Regulator Consumers:
+Consumer nodes can reference one or more of its supplies/
+regulators using the below bindings.
+
+- <name>-supply: phandle to the regulator node
+
+These are the same bindings that a regulator in the above
+example used to reference its own supply, in which case
+its just seen as a special case of a regulator being a
+consumer itself.
+
+Example of a consumer device node (mmc) referencing two
+regulators (twl-reg1 and twl-reg2),
+
+        twl-reg1: regulator@0 {
+                ...
+                ...
+                ...
+        };
+
+        twl-reg2: regulator@1 {
+                ...
+                ...
+                ...
+        };
+
+        mmc: mmc@0x0 {
+                ...
+                ...
+                vmmc-supply = <&twl-reg1>;
+                vmmcaux-supply = <&twl-reg2>;
+        };