bindings: spmi: add QTI Glink SPMI debug controller binding documentation

Qualcomm Technologies, Inc. Glink SPMI Debug Controller

The Qualcomm Technologies, Inc. Glink SPMI debug controller device provides an

interface to read and write PMIC registers over PMIC Glink using a remote

subsytem (e.g. DSP).  This allows for debugging PMIC peripherals that would

typically only be accessible to the charger and fuel gauging firmware running

on the remote subsystem.

Refer to Documentation/devicetree/bindings/soc/qcom/qcom,pmic-glink.txt for

information on "qcom,pmic_glink_log" device which is used in the example below.

See spmi.txt for the generic SPMI controller binding requirements for grandchild

nodes.

Required device node structure:

The Glink SPMI debug controller node must contain at least one child node.  Each

child node corresponds to an SPMI bus accessible from the remote subsystem.

Top Level Node Supported Properties:

- compatible:

	Usage:      required

	Value type: <stringlist>

	Definition: Must be "qcom,spmi-glink-debug".

Child Node Supported Properties:

- reg

	Usage:      required

	Value type: <u32>

	Definition: Bus ID of this SPMI bus.

Example:

&soc {

	qcom,pmic_glink_log {

		qcom,spmi_glink_debug {

			compatible = "qcom,spmi-glink-debug";

			#address-cells = <1>;

			#size-cells = <0>;

			spmi@0 {

				reg = <0>;

			};

			spmi@1 {

				reg = <1>;

			};

		};

	};

};