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.

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";

	};

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Nuvoton NPCM7xx Clock Generator binding

 * clock binding number for all clocks supportted by nuvoton,npcm7xx-clk

 *

 * Copyright (C) 2018 Nuvoton Technologies tali.perry@nuvoton.com

 *

 */

#ifndef __DT_BINDINGS_CLOCK_NPCM7XX_H

#define __DT_BINDINGS_CLOCK_NPCM7XX_H

#define NPCM7XX_CLK_CPU 0

#define NPCM7XX_CLK_GFX_PIXEL 1

#define NPCM7XX_CLK_MC 2

#define NPCM7XX_CLK_ADC 3

#define NPCM7XX_CLK_AHB 4

#define NPCM7XX_CLK_TIMER 5

#define NPCM7XX_CLK_UART 6

#define NPCM7XX_CLK_MMC  7

#define NPCM7XX_CLK_SPI3 8

#define NPCM7XX_CLK_PCI  9

#define NPCM7XX_CLK_AXI 10

#define NPCM7XX_CLK_APB4 11

#define NPCM7XX_CLK_APB3 12

#define NPCM7XX_CLK_APB2 13

#define NPCM7XX_CLK_APB1 14

#define NPCM7XX_CLK_APB5 15

#define NPCM7XX_CLK_CLKOUT 16

#define NPCM7XX_CLK_GFX  17

#define NPCM7XX_CLK_SU   18

#define NPCM7XX_CLK_SU48 19

#define NPCM7XX_CLK_SDHC 20

#define NPCM7XX_CLK_SPI0 21

#define NPCM7XX_CLK_SPIX 22

#define NPCM7XX_CLK_REFCLK 23

#define NPCM7XX_CLK_SYSBYPCK 24

#define NPCM7XX_CLK_MCBYPCK 25

#define NPCM7XX_NUM_CLOCKS	 (NPCM7XX_CLK_MCBYPCK+1)

#endif