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SubjectRe: [RFC PATCH 7/9] dt-bindings: power: avs: Add support for CPR (Core Power Reduction)
On Thu, Apr 04, 2019 at 07:09:28AM +0200, Niklas Cassel wrote:
> Add DT bindings to describe the CPR HW found on certain Qualcomm SoCs.
>
> Co-developed-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
> ---
> .../bindings/power/avs/qcom,cpr.txt | 119 ++++++++++++++++++
> 1 file changed, 119 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/power/avs/qcom,cpr.txt
>
> diff --git a/Documentation/devicetree/bindings/power/avs/qcom,cpr.txt b/Documentation/devicetree/bindings/power/avs/qcom,cpr.txt
> new file mode 100644
> index 000000000000..541c9b31cd3b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/avs/qcom,cpr.txt
> @@ -0,0 +1,119 @@
> +QCOM CPR (Core Power Reduction)
> +
> +CPR (Core Power Reduction) is a technology to reduce core power on a CPU
> +or other device. Each OPP of a device corresponds to a "corner" that has
> +a range of valid voltages for a particular frequency. While the device is
> +running at a particular frequency, CPR monitors dynamic factors such as
> +temperature, etc. and suggests adjustments to the voltage to save power
> +and meet silicon characteristic requirements.
> +
> +- compatible:
> + Usage: required
> + Value type: <string>
> + Definition: must be "qcom,cpr"

Needs to be SoC specific.

> +
> +- reg:
> + Usage: required
> + Value type: <prop-encoded-array>
> + Definition: base address and size of the rbcpr register region
> +
> +- interrupts:
> + Usage: required
> + Value type: <prop-encoded-array>
> + Definition: list of three interrupts in order of irq0, irq1, irq2

Does each irq have some defined meaning/function?

> +
> +- acc-syscon:
> + Usage: optional
> + Value type: <phandle>
> + Definition: phandle to syscon for writing ACC settings
> +
> +- nvmem:
> + Usage: required
> + Value type: <phandle>
> + Definition: phandle to nvmem provider containing efuse settings
> +
> +- nvmem-names:
> + Usage: required
> + Value type: <string>
> + Definition: must be "qfprom"
> +
> +vdd-mx-supply = <&pm8916_l3>;
> +
> +- qcom,cpr-ref-clk:
> + Usage: required
> + Value type: <u32>
> + Definition: rate of reference clock in kHz

Can't you use the clock binding for this?

> +
> +- qcom,cpr-timer-delay-us:
> + Usage: required
> + Value type: <u32>
> + Definition: delay in uS for the timer interval
> +
> +- qcom,cpr-timer-cons-up:
> + Usage: required
> + Value type: <u32>
> + Definition: Consecutive number of timer intervals, or units of
> + qcom,cpr-timer-delay-us, that occur before issuing an up
> + interrupt
> +
> +- qcom,cpr-timer-cons-down:
> + Usage: required
> + Value type: <u32>
> + Definition: Consecutive number of timer intervals, or units of
> + qcom,cpr-timer-delay-us, that occur before issuing a down
> + interrupt
> +
> +- qcom,cpr-up-threshold:
> + Usage: optional
> + Value type: <u32>
> + Definition: The threshold for CPR to issue interrupt when error_steps
> + is greater than it when stepping up
> +
> +- qcom,cpr-down-threshold:
> + Usage: optional
> + Value type: <u32>
> + Definition: The threshold for CPR to issue interrdownt when error_steps

typo

> + is greater than it when stepping down
> +
> +- qcom,cpr-down-threshold:
> + Usage: optional
> + Value type: <u32>
> + Definition: Idle clock cycles ring oscillator can be in
> +
> +- qcom,cpr-gcnt-us:
> + Usage: required
> + Value type: <u32>
> + Definition: The time for gate count in uS
> +
> +- qcom,vdd-apc-step-up-limit:
> + Usage: required
> + Value type: <u32>
> + Definition: Limit of vdd-apc-supply steps for scaling up

# of steps or a voltage?

> +
> +- qcom,vdd-apc-step-down-limit:
> + Usage: required
> + Value type: <u32>
> + Definition: Limit of vdd-apc-supply steps for scaling down
> +
> +Example:
> +
> + avs@b018000 {
> + compatible = "qcom,cpr";
> + reg = <0xb018000 0x1000>;
> + interrupts = <0 15 1>, <0 16 1>, <0 17 1>;
> + vdd-mx-supply = <&pm8916_l3>;
> + acc-syscon = <&tcsr>;
> + nvmem = <&qfprom>;
> + nvmem-names = "qfprom";
> +
> + qcom,cpr-ref-clk = <19200>;
> + qcom,cpr-timer-delay-us = <5000>;
> + qcom,cpr-timer-cons-up = <0>;
> + qcom,cpr-timer-cons-down = <2>;
> + qcom,cpr-up-threshold = <0>;
> + qcom,cpr-down-threshold = <2>;
> + qcom,cpr-idle-clocks = <15>;
> + qcom,cpr-gcnt-us = <1>;
> + qcom,vdd-apc-step-up-limit = <1>;
> + qcom,vdd-apc-step-down-limit = <1>;
> + };
> --
> 2.20.1
>

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