101 lines
2.8 KiB
Plaintext
Executable file
101 lines
2.8 KiB
Plaintext
Executable file
* Nuvoton NPCM7XX Clock Controller
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Nuvoton Poleg BMC NPCM7XX contains an integrated clock controller, which
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generates and supplies clocks to all modules within the BMC.
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External clocks:
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There are six fixed clocks that are generated outside the BMC. All clocks are of
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a known fixed value that cannot be changed. clk_refclk, clk_mcbypck and
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clk_sysbypck are inputs to the clock controller.
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clk_rg1refck, clk_rg2refck and clk_xin are external clocks suppling the
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network. They are set on the device tree, but not used by the clock module. The
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network devices use them directly.
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Example can be found below.
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All available clocks are defined as preprocessor macros in:
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dt-bindings/clock/nuvoton,npcm7xx-clock.h
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and can be reused as DT sources.
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Required Properties of clock controller:
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- compatible: "nuvoton,npcm750-clk" : for clock controller of Nuvoton
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Poleg BMC NPCM750
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- reg: physical base address of the clock controller and length of
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memory mapped region.
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- #clock-cells: should be 1.
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Example: Clock controller node:
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clk: clock-controller@f0801000 {
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compatible = "nuvoton,npcm750-clk";
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#clock-cells = <1>;
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reg = <0xf0801000 0x1000>;
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clock-names = "refclk", "sysbypck", "mcbypck";
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clocks = <&clk_refclk>, <&clk_sysbypck>, <&clk_mcbypck>;
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};
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Example: Required external clocks for network:
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/* external reference clock */
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clk_refclk: clk-refclk {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <25000000>;
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clock-output-names = "refclk";
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};
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/* external reference clock for cpu. float in normal operation */
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clk_sysbypck: clk-sysbypck {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <800000000>;
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clock-output-names = "sysbypck";
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};
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/* external reference clock for MC. float in normal operation */
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clk_mcbypck: clk-mcbypck {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <800000000>;
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clock-output-names = "mcbypck";
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};
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/* external clock signal rg1refck, supplied by the phy */
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clk_rg1refck: clk-rg1refck {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <125000000>;
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clock-output-names = "clk_rg1refck";
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};
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/* external clock signal rg2refck, supplied by the phy */
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clk_rg2refck: clk-rg2refck {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <125000000>;
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clock-output-names = "clk_rg2refck";
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};
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clk_xin: clk-xin {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <50000000>;
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clock-output-names = "clk_xin";
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};
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Example: GMAC controller node that consumes two clocks: a generated clk by the
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clock controller and a fixed clock from DT (clk_rg1refck).
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ethernet0: ethernet@f0802000 {
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compatible = "snps,dwmac";
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reg = <0xf0802000 0x2000>;
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interrupts = <0 14 4>;
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interrupt-names = "macirq";
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clocks = <&clk_rg1refck>, <&clk NPCM7XX_CLK_AHB>;
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clock-names = "stmmaceth", "clk_gmac";
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};
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