On 10/15, Linus Walleij wrote:
> 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
serialize ?
> +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
Furthermore?
> +these frequencies, the system controller must first be unlocked by
> +writing a special token to another offset in the system controller.
Sounds like a great design!
> +
> +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)
Is there any reason why we don't use a reg property for this?
> +- 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>;
lowercase the C?
> + clocks = <&xtal24mhz>;
> + };
> + (...)
> +};
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