The document describes the device tree binding for testing the IPCC
(Inter-Processor Communication Controller) driver. The test driver triggers a
self-ping onto itself. The expected behavior would be the driver raising
an interrupt using the mailbox interface onto the IPCC driver, which in turn
raises an interrupt on the IPCC hardware. Since the test driver is configured
as loopback, the interrupt generated should come back and hit the APPS
(Application Processor Subsystem). The IPCC driver would hear this interrupt
and forwards it to the IPCC test driver. Hence, the test exercises the inbound
and outbound paths of the driver.

For details on the IPCC driver, please see qcom,ipcc.txt

- compatible:
  Usage: required
  Value type: <string>
  Definition: Must be "qcom,ipcc-self-ping"

- interrupts-extended:
  Usage: required
  Value type: <prop-encoded-array>
  Definition: One entry specifying the phandle to the IPCC protocol, the APPS'
		client-id, signal-id and IRQ type.

- mboxes:
  Usage: required
  Value type: <prop-encoded-array>
  Definition: One entry specifying the phandle to the IPCC protocol, the APPS'
		client-id and the signal-id (same as interrupts-extended).

Example
-------
	ipcc_self_ping: ipcc-self-ping {
		compatible = "qcom,ipcc-self-ping";
		interrupts-extended = <&ipcc_mproc IPCC_CLIENT_APSS
				IPCC_MPROC_SIGNAL_SMP2P IRQ_TYPE_LEVEL_HIGH>;
		mboxes = <&ipcc_mproc IPCC_CLIENT_APSS IPCC_MPROC_SIGNAL_SMP2P>;
	};

