Documentation/devicetree/bindings/arm/msm/msm_pp2s.txt

QTI Femtocell Pulse Per 2 Second (PP2S)

PP2S is a hardware generated pulse that occurs every two seconds and
is used for synchronizing certain system behaviors as they relate to
time.

The PP2S notification driver will be used by applications for two
reasons:

  1) So that they can be informed when PP2S interrupts occur, and

  2) So that the wall clock time registers can be accessed/manipulated
     from within the driver and from user space.

Two device tree nodes have been added.

The first is for the PP2S interrupt. It is made up of the following
required properties:

- compatible: "qcom,pp2s"
- interrupts: The interrupt number
- interrupt-names: the interrupt name

Example:

    qcom,pp2s {
        compatible = "qcom,pp2s";
        interrupts = <0 219 0>;
        interrupt-names = "pp2s_irq";
    };

The second is for mapping the wall clock regisers into usable
memory. It is made up of the required following:

- compatible: "qcom,wallclock"
- reg-names: The names given to the memory bank locations
- reg: The base address and length for each bank

Example:

    qcom,wallclock@fd4aa000 {
        compatible = "qcom,wallclock";
        reg-names = "wallclock_time_bank", "wallclock_cntrl_bank1", "wallclock_cntrl_bank2";
        reg = <0xfd4aa000 0x20>, <0xfd4a9000 0x40>, <0xfd4a3200 0x04>;
    };