xref: /openbmc/linux/Documentation/devicetree/bindings/clock/qoriq-clock.txt (revision eaf76b21)

* 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.

All references to "1.0" and "2.0" refer to the QorIQ chassis version to
which the chip complies.

Chassis Version		Example Chips
---------------		-------------
1.0			p4080, p5020, p5040
2.0			t4240, b4860, t1040

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>;
		...
	};
  }