dt-bindings: Introduce interconnect binding

This binding is intended to represent the relations between interconnect
controllers (providers) and consumer device nodes. It will allow creating
links between consumers and interconnect paths (exposed by interconnect
providers).

Reviewed-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/interconnect/interconnect.txt b/Documentation/devicetree/bindings/interconnect/interconnect.txt
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+Interconnect Provider Device Tree Bindings
+=========================================
+
+The purpose of this document is to define a common set of generic interconnect
+providers/consumers properties.
+
+
+= interconnect providers =
+
+The interconnect provider binding is intended to represent the interconnect
+controllers in the system. Each provider registers a set of interconnect
+nodes, which expose the interconnect related capabilities of the interconnect
+to consumer drivers. These capabilities can be throughput, latency, priority
+etc. The consumer drivers set constraints on interconnect path (or endpoints)
+depending on the use case. Interconnect providers can also be interconnect
+consumers, such as in the case where two network-on-chip fabrics interface
+directly.
+
+Required properties:
+- compatible : contains the interconnect provider compatible string
+- #interconnect-cells : number of cells in a interconnect specifier needed to
+                       encode the interconnect node id
+
+Example:
+
+               snoc: interconnect@580000 {
+                       compatible = "qcom,msm8916-snoc";
+                       #interconnect-cells = <1>;
+                       reg = <0x580000 0x14000>;
+                       clock-names = "bus_clk", "bus_a_clk";
+                       clocks = <&rpmcc RPM_SMD_SNOC_CLK>,
+                                <&rpmcc RPM_SMD_SNOC_A_CLK>;
+               };
+
+
+= interconnect consumers =
+
+The interconnect consumers are device nodes which dynamically express their
+bandwidth requirements along interconnect paths they are connected to. There
+can be multiple interconnect providers on a SoC and the consumer may consume
+multiple paths from different providers depending on use case and the
+components it has to interact with.
+
+Required properties:
+interconnects : Pairs of phandles and interconnect provider specifier to denote
+               the edge source and destination ports of the interconnect path.
+
+Optional properties:
+interconnect-names : List of interconnect path name strings sorted in the same
+                    order as the interconnects property. Consumers drivers will use
+                    interconnect-names to match interconnect paths with interconnect
+                    specifier pairs.
+
+Example:
+
+       sdhci@7864000 {
+               ...
+               interconnects = <&pnoc MASTER_SDCC_1 &bimc SLAVE_EBI_CH0>;
+               interconnect-names = "sdhc-mem";
+       };