|
@@ -0,0 +1,47 @@
|
|
|
+* Actions S900 Clock Management Unit (CMU)
|
|
|
+
|
|
|
+The Actions S900 clock management unit generates and supplies clock to various
|
|
|
+controllers within the SoC. The clock binding described here is applicable to
|
|
|
+S900 SoC.
|
|
|
+
|
|
|
+Required Properties:
|
|
|
+
|
|
|
+- compatible: should be "actions,s900-cmu"
|
|
|
+- reg: physical base address of the controller and length of memory mapped
|
|
|
+ region.
|
|
|
+- clocks: Reference to the parent clocks ("hosc", "losc")
|
|
|
+- #clock-cells: should be 1.
|
|
|
+
|
|
|
+Each clock is assigned an identifier, and client nodes can use this identifier
|
|
|
+to specify the clock which they consume.
|
|
|
+
|
|
|
+All available clocks are defined as preprocessor macros in
|
|
|
+dt-bindings/clock/actions,s900-cmu.h header and can be used in device
|
|
|
+tree sources.
|
|
|
+
|
|
|
+External clocks:
|
|
|
+
|
|
|
+The hosc clock used as input for the plls is generated outside the SoC. It is
|
|
|
+expected that it is defined using standard clock bindings as "hosc".
|
|
|
+
|
|
|
+Actions S900 CMU also requires one more clock:
|
|
|
+ - "losc" - internal low frequency oscillator
|
|
|
+
|
|
|
+Example: Clock Management Unit node:
|
|
|
+
|
|
|
+ cmu: clock-controller@e0160000 {
|
|
|
+ compatible = "actions,s900-cmu";
|
|
|
+ reg = <0x0 0xe0160000 0x0 0x1000>;
|
|
|
+ clocks = <&hosc>, <&losc>;
|
|
|
+ #clock-cells = <1>;
|
|
|
+ };
|
|
|
+
|
|
|
+Example: UART controller node that consumes clock generated by the clock
|
|
|
+management unit:
|
|
|
+
|
|
|
+ uart: serial@e012a000 {
|
|
|
+ compatible = "actions,s900-uart", "actions,owl-uart";
|
|
|
+ reg = <0x0 0xe012a000 0x0 0x2000>;
|
|
|
+ interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
|
|
|
+ clocks = <&cmu CLK_UART5>;
|
|
|
+ };
|