213 lines
6.6 KiB
Plaintext
213 lines
6.6 KiB
Plaintext
* Clock Block on Freescale QorIQ Platforms
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Freescale QorIQ chips take primary clocking input from the external
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SYSCLK signal. The SYSCLK input (frequency) is multiplied using
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multiple phase locked loops (PLL) to create a variety of frequencies
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which can then be passed to a variety of internal logic, including
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cores and peripheral IP blocks.
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Please refer to the Reference Manual for details.
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All references to "1.0" and "2.0" refer to the QorIQ chassis version to
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which the chip complies.
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Chassis Version Example Chips
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--------------- -------------
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1.0 p4080, p5020, p5040
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2.0 t4240, b4860
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1. Clock Block Binding
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Required properties:
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- compatible: Should contain a chip-specific clock block compatible
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string and (if applicable) may contain a chassis-version clock
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compatible string.
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Chip-specific strings are of the form "fsl,<chip>-clockgen", such as:
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* "fsl,p2041-clockgen"
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* "fsl,p3041-clockgen"
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* "fsl,p4080-clockgen"
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* "fsl,p5020-clockgen"
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* "fsl,p5040-clockgen"
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* "fsl,t1023-clockgen"
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* "fsl,t1024-clockgen"
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* "fsl,t1040-clockgen"
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* "fsl,t1042-clockgen"
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* "fsl,t2080-clockgen"
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* "fsl,t2081-clockgen"
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* "fsl,t4240-clockgen"
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* "fsl,b4420-clockgen"
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* "fsl,b4860-clockgen"
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* "fsl,ls1012a-clockgen"
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* "fsl,ls1021a-clockgen"
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* "fsl,ls1028a-clockgen"
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* "fsl,ls1043a-clockgen"
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* "fsl,ls1046a-clockgen"
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* "fsl,ls1088a-clockgen"
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* "fsl,ls2080a-clockgen"
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* "fsl,lx2160a-clockgen"
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Chassis-version clock strings include:
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* "fsl,qoriq-clockgen-1.0": for chassis 1.0 clocks
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* "fsl,qoriq-clockgen-2.0": for chassis 2.0 clocks
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- reg: Describes the address of the device's resources within the
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address space defined by its parent bus, and resource zero
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represents the clock register set
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Optional properties:
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- ranges: Allows valid translation between child's address space and
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parent's. Must be present if the device has sub-nodes.
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- #address-cells: Specifies the number of cells used to represent
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physical base addresses. Must be present if the device has
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sub-nodes and set to 1 if present
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- #size-cells: Specifies the number of cells used to represent
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the size of an address. Must be present if the device has
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sub-nodes and set to 1 if present
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- clock-frequency: Input system clock frequency (SYSCLK)
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- clocks: If clock-frequency is not specified, sysclk may be provided
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as an input clock. Either clock-frequency or clocks must be
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provided.
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A second input clock, called "coreclk", may be provided if
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core PLLs are based on a different input clock from the
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platform PLL.
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- clock-names: Required if a coreclk is present. Valid names are
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"sysclk" and "coreclk".
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2. Clock Provider
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The clockgen node should act as a clock provider, though in older device
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trees the children of the clockgen node are the clock providers.
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When the clockgen node is a clock provider, #clock-cells = <2>.
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The first cell of the clock specifier is the clock type, and the
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second cell is the clock index for the specified type.
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Type# Name Index Cell
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0 sysclk must be 0
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1 cmux index (n in CLKCnCSR)
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2 hwaccel index (n in CLKCGnHWACSR)
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3 fman 0 for fm1, 1 for fm2
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4 platform pll n=pll/(n+1). For example, when n=1,
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that means output_freq=PLL_freq/2.
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5 coreclk must be 0
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3. Example
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clockgen: global-utilities@e1000 {
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compatible = "fsl,p5020-clockgen", "fsl,qoriq-clockgen-1.0";
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clock-frequency = <133333333>;
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reg = <0xe1000 0x1000>;
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#clock-cells = <2>;
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};
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fman@400000 {
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...
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clocks = <&clockgen 3 0>;
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...
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};
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}
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4. Legacy Child Nodes
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NOTE: These nodes are deprecated. Kernels should continue to support
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device trees with these nodes, but new device trees should not use them.
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Most of the bindings are from the common clock binding[1].
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[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
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Required properties:
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- compatible : Should include one of the following:
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* "fsl,qoriq-core-pll-1.0" for core PLL clocks (v1.0)
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* "fsl,qoriq-core-pll-2.0" for core PLL clocks (v2.0)
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* "fsl,qoriq-core-mux-1.0" for core mux clocks (v1.0)
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* "fsl,qoriq-core-mux-2.0" for core mux clocks (v2.0)
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* "fsl,qoriq-sysclk-1.0": for input system clock (v1.0).
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It takes parent's clock-frequency as its clock.
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* "fsl,qoriq-sysclk-2.0": for input system clock (v2.0).
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It takes parent's clock-frequency as its clock.
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* "fsl,qoriq-platform-pll-1.0" for the platform PLL clock (v1.0)
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* "fsl,qoriq-platform-pll-2.0" for the platform PLL clock (v2.0)
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- #clock-cells: From common clock binding. The number of cells in a
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clock-specifier. Should be <0> for "fsl,qoriq-sysclk-[1,2].0"
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clocks, or <1> for "fsl,qoriq-core-pll-[1,2].0" clocks.
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For "fsl,qoriq-core-pll-[1,2].0" clocks, the single
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clock-specifier cell may take the following values:
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* 0 - equal to the PLL frequency
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* 1 - equal to the PLL frequency divided by 2
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* 2 - equal to the PLL frequency divided by 4
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Recommended properties:
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- clocks: Should be the phandle of input parent clock
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- clock-names: From common clock binding, indicates the clock name
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- clock-output-names: From common clock binding, indicates the names of
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output clocks
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- reg: Should be the offset and length of clock block base address.
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The length should be 4.
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Legacy Example:
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/ {
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clockgen: global-utilities@e1000 {
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compatible = "fsl,p5020-clockgen", "fsl,qoriq-clockgen-1.0";
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ranges = <0x0 0xe1000 0x1000>;
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clock-frequency = <133333333>;
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reg = <0xe1000 0x1000>;
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#address-cells = <1>;
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#size-cells = <1>;
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sysclk: sysclk {
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#clock-cells = <0>;
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compatible = "fsl,qoriq-sysclk-1.0";
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clock-output-names = "sysclk";
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};
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pll0: pll0@800 {
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#clock-cells = <1>;
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reg = <0x800 0x4>;
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compatible = "fsl,qoriq-core-pll-1.0";
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clocks = <&sysclk>;
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clock-output-names = "pll0", "pll0-div2";
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};
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pll1: pll1@820 {
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#clock-cells = <1>;
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reg = <0x820 0x4>;
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compatible = "fsl,qoriq-core-pll-1.0";
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clocks = <&sysclk>;
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clock-output-names = "pll1", "pll1-div2";
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};
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mux0: mux0@0 {
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#clock-cells = <0>;
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reg = <0x0 0x4>;
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compatible = "fsl,qoriq-core-mux-1.0";
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clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
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clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
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clock-output-names = "cmux0";
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};
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mux1: mux1@20 {
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#clock-cells = <0>;
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reg = <0x20 0x4>;
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compatible = "fsl,qoriq-core-mux-1.0";
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clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
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clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
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clock-output-names = "cmux1";
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};
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platform-pll: platform-pll@c00 {
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#clock-cells = <1>;
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reg = <0xc00 0x4>;
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compatible = "fsl,qoriq-platform-pll-1.0";
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clocks = <&sysclk>;
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clock-output-names = "platform-pll", "platform-pll-div2";
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};
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};
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};
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Example for legacy clock consumer:
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/ {
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cpu0: PowerPC,e5500@0 {
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...
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clocks = <&mux0>;
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...
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};
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};
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