Re: [PATCH 08/13] clk: add ARM syscon ICST device tree bindings
On 10/23, Linus Walleij wrote: > On Thu, Oct 15, 2015 at 9:23 PM, Stephen Boyd wrote: > > On 10/15, Linus Walleij wrote: > > >> +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? > > Usually reg = <> is used with two (or more) tokens: > > reg = ; > > The exception being things like I2C addresses which > are just one token. > > Since in this case, there is a "mother" reg property in the > syscon-compatible node, which we are indexing into, > it is confusing to use the same name for subnodes. > > Also there is a bunch of precedents doing it like this > for sybdevices to system controllers, just > git grep offset Documentation/devicetree/bindings > will give you a bunch of them. > Ok. I'm no DT expert, but it seems odd to have subnodes without a reg property. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 08/13] clk: add ARM syscon ICST device tree bindings
On Thu, Oct 15, 2015 at 9:23 PM, Stephen Boyd wrote: > On 10/15, Linus Walleij wrote: >> +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? Usually reg = <> is used with two (or more) tokens: reg = ; The exception being things like I2C addresses which are just one token. Since in this case, there is a "mother" reg property in the syscon-compatible node, which we are indexing into, it is confusing to use the same name for subnodes. Also there is a bunch of precedents doing it like this for sybdevices to system controllers, just git grep offset Documentation/devicetree/bindings will give you a bunch of them. (Fixing the spelling comments.) Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 08/13] clk: add ARM syscon ICST device tree bindings
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 ..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@1000 {
> + compatible = "syscon";
> + reg = <0x1000 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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[PATCH 08/13] clk: add ARM syscon ICST device tree bindings
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@vger.kernel.org
Cc: Michael Turquette
Cc: Stephen Boyd
Cc: linux-...@vger.kernel.org
Signed-off-by: Linus Walleij
---
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 ..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@1000 {
+ compatible = "syscon";
+ reg = <0x1000 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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