clk: corenet: Adds the clock binding

Adds the clock bindings for Freescale PowerPC CoreNet platforms
Signed-off-by: NTang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: NLi Yang <leoli@freescale.com>
[scottwood@freescale.com: fixed clock-frequency in example]
Signed-off-by: NScott Wood <scottwood@freescale.com>

Documentation/devicetree/bindings/clock/corenet-clock.txt

+* Clock Block on Freescale CoreNet Platforms
+
+Freescale CoreNet chips take primary clocking input from the external
+SYSCLK signal. The SYSCLK input (frequency) is multiplied using
+multiple phase locked loops (PLL) to create a variety of frequencies
+which can then be passed to a variety of internal logic, including
+cores and peripheral IP blocks.
+Please refer to the Reference Manual for details.
+
+1. Clock Block Binding
+
+Required properties:
+- compatible: Should contain a specific clock block compatible string
+	and a single chassis clock compatible string.
+	Clock block strings include, but not limited to, one of the:
+	* "fsl,p2041-clockgen"
+	* "fsl,p3041-clockgen"
+	* "fsl,p4080-clockgen"
+	* "fsl,p5020-clockgen"
+	* "fsl,p5040-clockgen"
+	* "fsl,t4240-clockgen"
+	* "fsl,b4420-clockgen"
+	* "fsl,b4860-clockgen"
+	Chassis clock strings include:
+	* "fsl,qoriq-clockgen-1.0": for chassis 1.0 clocks
+	* "fsl,qoriq-clockgen-2.0": for chassis 2.0 clocks
+- reg: Describes the address of the device's resources within the
+	address space defined by its parent bus, and resource zero
+	represents the clock register set
+- clock-frequency: Input system clock frequency
+
+Recommended properties:
+- ranges: Allows valid translation between child's address space and
+	parent's. Must be present if the device has sub-nodes.
+- #address-cells: Specifies the number of cells used to represent
+	physical base addresses.  Must be present if the device has
+	sub-nodes and set to 1 if present
+- #size-cells: Specifies the number of cells used to represent
+	the size of an address. Must be present if the device has
+	sub-nodes and set to 1 if present
+
+2. Clock Provider/Consumer Binding
+
+Most of the bindings are from the common clock binding[1].
+ [1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : Should include one of the following:
+	* "fsl,qoriq-core-pll-1.0" for core PLL clocks (v1.0)
+	* "fsl,qoriq-core-pll-2.0" for core PLL clocks (v2.0)
+	* "fsl,qoriq-core-mux-1.0" for core mux clocks (v1.0)
+	* "fsl,qoriq-core-mux-2.0" for core mux clocks (v2.0)
+	* "fsl,qoriq-sysclk-1.0": for input system clock (v1.0).
+		It takes parent's clock-frequency as its clock.
+	* "fsl,qoriq-sysclk-2.0": for input system clock (v2.0).
+		It takes parent's clock-frequency as its clock.
+- #clock-cells: From common clock binding. The number of cells in a
+	clock-specifier. Should be <0> for "fsl,qoriq-sysclk-[1,2].0"
+	clocks, or <1> for "fsl,qoriq-core-pll-[1,2].0" clocks.
+	For "fsl,qoriq-core-pll-[1,2].0" clocks, the single
+	clock-specifier cell may take the following values:
+	* 0 - equal to the PLL frequency
+	* 1 - equal to the PLL frequency divided by 2
+	* 2 - equal to the PLL frequency divided by 4
+
+Recommended properties:
+- clocks: Should be the phandle of input parent clock
+- clock-names: From common clock binding, indicates the clock name
+- clock-output-names: From common clock binding, indicates the names of
+	output clocks
+- reg: Should be the offset and length of clock block base address.
+	The length should be 4.
+
+Example for clock block and clock provider:
+/ {
+	clockgen: global-utilities@e1000 {
+		compatible = "fsl,p5020-clockgen", "fsl,qoriq-clockgen-1.0";
+		ranges = <0x0 0xe1000 0x1000>;
+		clock-frequency = <133333333>;
+		reg = <0xe1000 0x1000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		sysclk: sysclk {
+			#clock-cells = <0>;
+			compatible = "fsl,qoriq-sysclk-1.0";
+			clock-output-names = "sysclk";
+		}
+
+		pll0: pll0@800 {
+			#clock-cells = <1>;
+			reg = <0x800 0x4>;
+			compatible = "fsl,qoriq-core-pll-1.0";
+			clocks = <&sysclk>;
+			clock-output-names = "pll0", "pll0-div2";
+		};
+
+		pll1: pll1@820 {
+			#clock-cells = <1>;
+			reg = <0x820 0x4>;
+			compatible = "fsl,qoriq-core-pll-1.0";
+			clocks = <&sysclk>;
+			clock-output-names = "pll1", "pll1-div2";
+		};
+
+		mux0: mux0@0 {
+			#clock-cells = <0>;
+			reg = <0x0 0x4>;
+			compatible = "fsl,qoriq-core-mux-1.0";
+			clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
+			clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
+			clock-output-names = "cmux0";
+		};
+
+		mux1: mux1@20 {
+			#clock-cells = <0>;
+			reg = <0x20 0x4>;
+			compatible = "fsl,qoriq-core-mux-1.0";
+			clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
+			clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
+			clock-output-names = "cmux1";
+		};
+	};
+  }
+
+Example for clock consumer:
+
+/ {
+	cpu0: PowerPC,e5500@0 {
+		...
+		clocks = <&mux0>;
+		...
+	};
+  }