This adds the device tree bindings for the ARM Syscon ICST
oscillators, which is a register-level interface to the
Integrated Device Technology (IDT) ICS525 and ICS307
serially programmable oscillators.
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Cc: linux-clk@xxxxxxxxxxxxxxx
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
I'm looking for an ACK from the CLK maintainers to take this
through the ARM SoC tree once the series stabilize.
---
.../devicetree/bindings/clock/arm-syscon-icst.txt | 40 ++++++++++++++++++++++
1 file changed, 40 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/arm-syscon-icst.txt
diff --git a/Documentation/devicetree/bindings/clock/arm-syscon-icst.txt b/Documentation/devicetree/bindings/clock/arm-syscon-icst.txt
new file mode 100644
index 000000000000..19eb3aa765c7
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/arm-syscon-icst.txt
@@ -0,0 +1,40 @@
+ARM System Controller ICST clocks
+
+The ICS525 and ICS307 oscillators are produced by Integrated Devices
+Technology (IDT). ARM integrated these oscillators deeply into their
+reference designs by adding special control registers that manage such
+oscillators to their system controllers.
+
+The ARM system controller contains logic to serialized and initialize
+an ICST clock request after a write to the 32 bit register at an offset
+into the system controller. Further, to even be able to alter one of
+these frequencies, the system controller must first be unlocked by
+writing a special token to another offset in the system controller.
+
+The ICST oscillator must be provided inside a system controller node.
+
+Required properties:
+- lock-offset: the offset address into the system controller where the
+ unlocking register is located
+- vco-offset: the offset address into the system controller where the
+ ICST control register is located (even 32 bit address)
+- compatible: must be one of "arm,syscon-icst525" or "arm,syscon-icst307"
+- #clock-cells: must be <0>
+- clocks: parent clock, since the ICST needs a parent clock to derive its
+ frequency from, this attribute is compulsory.
+
+Example:
+
+syscon: syscon@10000000 {
+ compatible = "syscon";
+ reg = <0x10000000 0x1000>;
+
+ oscclk0: osc0@0c {
+ compatible = "arm,syscon-icst307";
+ #clock-cells = <0>;
+ lock-offset = <0x20>;
+ vco-offset = <0x0C>;
+ clocks = <&xtal24mhz>;
+ };
+ (...)
+};
--
2.4.3
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