[RFC PATCH 4/6] devicetree: bindings: add documentation for voltagedomain

Nishanth Menon
2014-02-18T20:32:21Z

Add documentation for voltage domain binding format. Specific
voltage domains will have bindings corresponding to them.

Signed-off-by: Nishanth Menon <nm@ti.com>
---
.../bindings/power/voltdm/voltage_domain.txt | 65 ++++++++++++++++++++
1 file changed, 65 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/voltdm/voltage_domain.txt

diff --git a/Documentation/devicetree/bindings/power/voltdm/voltage_domain.txt b/Documentation/devicetree/bindings/power/voltdm/voltage_domain.txt
new file mode 100644
index 0000000..da48a19
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/voltdm/voltage_domain.txt
@@ -0,0 +1,65 @@
+Specifying Voltage Domain information for devices
+=================================================
+
+1. Specifying a voltage domain.
+
+SoCs may have multiple voltage domains under which various clocks operate.
+
+Mandatory Properties:
+- #voltdm-cells - indicates if there are specifiers needed to reference the
+ voltage domain
+
+Optional Properties:
+- voltage-tolerance: Specify the voltage tolerance in percentage
+
+2. Voltage domain consumer
+consumer nodes can be reference using the below binding:
+- <name>-voltdm: phandle to the voltage domain node.
+
+Examples:
+
+A. Voltage Domain controlling multiple regulator
+voltage_domain_mpu: voltdm@1 {
+ compatible = "xyz";
+ #voltdm-cells = <0>;
+ vdd-supply = <&vcc>;
+ vbb-supply = <&abb_mpu>;
+ ...
+};
+
+voltage_domain_gpu: voltdm@2 {
+ compatible = "xyz";
+ #voltdm-cells = <0>;
+ vdd-supply = <&dcdc2>;
+ vbb-supply = <&abb_gpu>;
+ ...
+};
+...
+&cpu0 {
+ cpu0-voltdm = <&voltage_domain_mpu>;
+ voltage-tolerance = <1>;
+};
+
+&gpu {
+ gpu-voltdm = <&voltage_domain_gpu>;
+};
+
+B. Indexed voltage domain device
+
+#define SOC_XYZ_VOLTAGE_DOMAIN_MPU 0
+#define SOC_XYZ_VOLTAGE_DOMAIN_GFX 1
+
+voltage_domain_socx: voltdm@1 {
+ compatible = "abc";
+ #voltdm-cells = <1>;
+ ...
+};
+...
+&cpu0 {
+ cpu0-voltdm = <&voltage_domain_socx SOC_XYZ_VOLTAGE_DOMAIN_MPU>;
+ voltage-tolerance = <1>;
+};
+
+&gpu {
+ gpu-voltdm = <&voltage_domain_socx SOC_XYZ_VOLTAGE_DOMAIN_GFX>;
+};
--
1.7.9.5