dt-binding: clk: npcm750: Add binding for Nuvoton NPCM7XX Clock

* Nuvoton NPCM7XX Clock Controller

Nuvoton Poleg BMC NPCM7XX contains an integrated clock controller, which
generates and supplies clocks to all modules within the BMC.

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/clock/nuvoton,npcm750-clk.txt b/Documentation/devicetree/bindings/clock/nuvoton,npcm750-clk.txt
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index 000000000000..f82064546d11
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+++ b/Documentation/devicetree/bindings/clock/nuvoton,npcm750-clk.txt
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+* Nuvoton NPCM7XX Clock Controller
+
+Nuvoton Poleg BMC NPCM7XX contains an integrated clock controller, which
+generates and supplies clocks to all modules within the BMC.
+
+External clocks:
+
+There are six fixed clocks that are generated outside the BMC. All clocks are of
+a known fixed value that cannot be changed. clk_refclk, clk_mcbypck and
+clk_sysbypck are inputs to the clock controller.
+clk_rg1refck, clk_rg2refck and clk_xin are external clocks suppling the
+network. They are set on the device tree, but not used by the clock module. The
+network devices use them directly.
+Example can be found below.
+
+All available clocks are defined as preprocessor macros in:
+dt-bindings/clock/nuvoton,npcm7xx-clock.h
+and can be reused as DT sources.
+
+Required Properties of clock controller:
+
+	- compatible: "nuvoton,npcm750-clk" : for clock controller of Nuvoton
+		  Poleg BMC NPCM750
+
+	- reg: physical base address of the clock controller and length of
+		memory mapped region.
+
+	- #clock-cells: should be 1.
+
+Example: Clock controller node:
+
+	clk: clock-controller@f0801000 {
+		compatible = "nuvoton,npcm750-clk";
+		#clock-cells = <1>;
+		reg = <0xf0801000 0x1000>;
+		clock-names = "refclk", "sysbypck", "mcbypck";
+		clocks = <&clk_refclk>, <&clk_sysbypck>, <&clk_mcbypck>;
+	};
+
+Example: Required external clocks for network:
+
+	/* external reference clock */
+	clk_refclk: clk-refclk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <25000000>;
+		clock-output-names = "refclk";
+	};
+
+	/* external reference clock for cpu. float in normal operation */
+	clk_sysbypck: clk-sysbypck {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <800000000>;
+		clock-output-names = "sysbypck";
+	};
+
+	/* external reference clock for MC. float in normal operation */
+	clk_mcbypck: clk-mcbypck {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <800000000>;
+		clock-output-names = "mcbypck";
+	};
+
+	 /* external clock signal rg1refck, supplied by the phy */
+	clk_rg1refck: clk-rg1refck {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <125000000>;
+		clock-output-names = "clk_rg1refck";
+	};
+
+	 /* external clock signal rg2refck, supplied by the phy */
+	clk_rg2refck: clk-rg2refck {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <125000000>;
+		clock-output-names = "clk_rg2refck";
+	};
+
+	clk_xin: clk-xin {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <50000000>;
+		clock-output-names = "clk_xin";
+	};
+
+
+Example: GMAC controller node that consumes two clocks: a generated clk by the
+clock controller and a fixed clock from DT (clk_rg1refck).
+
+	ethernet0: ethernet@f0802000 {
+		compatible = "snps,dwmac";
+		reg = <0xf0802000 0x2000>;
+		interrupts = <0 14 4>;
+		interrupt-names = "macirq";
+		clocks	= <&clk_rg1refck>, <&clk NPCM7XX_CLK_AHB>;
+		clock-names = "stmmaceth", "clk_gmac";
+	};