xref: /kernel/linux/linux-5.10/Documentation/devicetree/bindings/clock/samsung,s3c64xx-clock.txt

* Samsung S3C64xx Clock Controller

The S3C64xx clock controller generates and supplies clock to various controllers
within the SoC. The clock binding described here is applicable to all SoCs in
the S3C64xx family.

Required Properties:

- compatible: should be one of the following.
  - "samsung,s3c6400-clock" - controller compatible with S3C6400 SoC.
  - "samsung,s3c6410-clock" - controller compatible with S3C6410 SoC.

- reg: physical base address of the controller and length of memory mapped
  region.

- #clock-cells: should be 1.

Each clock is assigned an identifier and client nodes can use this identifier
to specify the clock which they consume. Some of the clocks are available only
on a particular S3C64xx SoC and this is specified where applicable.

All available clocks are defined as preprocessor macros in
dt-bindings/clock/samsung,s3c64xx-clock.h header and can be used in device
tree sources.

External clocks:

There are several clocks that are generated outside the SoC. It is expected
that they are defined using standard clock bindings with following
clock-output-names:
 - "fin_pll" - PLL input clock (xtal/extclk) - required,
 - "xusbxti" - USB xtal - required,
 - "iiscdclk0" - I2S0 codec clock - optional,
 - "iiscdclk1" - I2S1 codec clock - optional,
 - "iiscdclk2" - I2S2 codec clock - optional,
 - "pcmcdclk0" - PCM0 codec clock - optional,
 - "pcmcdclk1" - PCM1 codec clock - optional, only S3C6410.

Example: Clock controller node:

	clock: clock-controller@7e00f000 {
		compatible = "samsung,s3c6410-clock";
		reg = <0x7e00f000 0x1000>;
		#clock-cells = <1>;
	};

Example: Required external clocks:

	fin_pll: clock-fin-pll {
		compatible = "fixed-clock";
		clock-output-names = "fin_pll";
		clock-frequency = <12000000>;
		#clock-cells = <0>;
	};

	xusbxti: clock-xusbxti {
		compatible = "fixed-clock";
		clock-output-names = "xusbxti";
		clock-frequency = <48000000>;
		#clock-cells = <0>;
	};

Example: UART controller node that consumes the clock generated by the clock
  controller (refer to the standard clock bindings for information about
  "clocks" and "clock-names" properties):

		uart0: serial@7f005000 {
			compatible = "samsung,s3c6400-uart";
			reg = <0x7f005000 0x100>;
			interrupt-parent = <&vic1>;
			interrupts = <5>;
			clock-names = "uart", "clk_uart_baud2",
					"clk_uart_baud3";
			clocks = <&clock PCLK_UART0>, <&clocks PCLK_UART0>,
					<&clock SCLK_UART>;
		};