dt-bindings: Add device-tree bindings for Watchdog driver

%YAML 1.2

---

$id: http://devicetree.org/schemas/bindings/arm/msm/msm_watchdog.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: QTI MSM Watchdog

maintainers:

  - Prakruthi Deepak Heragu <pheragu@quicinc.com>

description: |+

  Watchdog timer is configured with a bark and a bite time.

  If the watchdog is not "pet" at regular intervals, the system

  is assumed to have become non responsive and needs to be reset.

  A warning in the form of a bark timeout leads to a bark interrupt

  and a kernel panic. If the watchdog timer is still not reset,

  a bite timeout occurs, which is an interrupt in the secure mode,

  which leads to a reset of the SOC via the secure watchdog. The

  driver needs the petting time, and the bark timeout to be programmed

  into the watchdog, as well as the bark and bite irqs.

  The device tree parameters for the watchdog are:

properties:

  compatible:

    Usage: required

    Value type: <string>

    Definition: Must be "qcom,msm-watchdog"

  reg:

    Usage: required

    Value type: <prop-encoded-array>

    Definition: offset and length of the register set for the watchdog block.

  reg-names:

    Usage: required

    Value type: <string>

    Definition: names corresponding to each reg property value (base required).

          "wdt-base" - physical base address of watchdog timer registers

          "wdt-absent-base" - physical base address of watchdog absent register

  interrupts:

     Usage: required

     Value type: <prop-encoded-array>

     Definition: should contain bark and bite irq numbers

  qcom,pet-time:

     Usage: required

     Value type: <u32>

     Definition: Non zero time interval at which watchdog should be pet in ms.

  qcom,bark-time:

     Usage: required

     Value type: <u32>

     Definition: Non zero timeout value for a watchdog bark in ms.

  qcom,userspace-watchdog:

     Usage: optional

     Value type: <boolean>

     Definition: Allow enabling the userspace-watchdog feature. This feature

          requires userspace to pet the watchdog every qcom,pet-time interval

          in addition to the existing kernel-level checks.

          This feature is supported through device sysfs files.

  qcom,ipi-ping:

     Usage: optional

     Value type: <boolean>

     Definition: send keep alive ping to other cpus if present

  qcom,wakeup-enable:

     Usage: optional

     Value type: <boolean>

     Definition: enable non secure watchdog to freeze / unfreeze

          automatically across suspend / resume path.

example:

  - |

    wdog: qcom,wdt@17c10000{

	compatible = "qcom,msm-watchdog";

	reg = <0x17c10000 0x1000>;

	reg-names = "wdt-base";

	interrupts = <0 0 IRQ_TYPE_LEVEL_HIGH>,

                <0 1 IRQ_TYPE_LEVEL_HIGH>;

	qcom,bark-time = <11000>;

	qcom,pet-time = <9360>;

	qcom,ipi-ping;

	qcom,wakeup-enable;

    };

...