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authorSascha Hauer <s.hauer@pengutronix.de>2016-02-03 10:25:36 +0100
committerSascha Hauer <s.hauer@pengutronix.de>2016-02-04 08:40:36 +0100
commit0ff58575c9d66f660886387c2e68d8c5c724e87b (patch)
tree4a889d1478da83ae46db96f5c049872cdb90eeb6 /dts/Bindings/clock/arm-syscon-icst.txt
parenta0da52f83c36a81984e0fca4b75d522b955df267 (diff)
downloadbarebox-0ff58575c9d66f660886387c2e68d8c5c724e87b.tar.gz
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dts: update to v4.5-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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+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 serialize and initialize
+an ICST clock request after a write to the 32 bit register at an offset
+into the system controller. Furthermore, 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>;
+ };
+ (...)
+};