xref: /freebsd/sys/contrib/device-tree/Bindings/clock/exynos4-clock.txt (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)

* Samsung Exynos4 Clock Controller

The Exynos4 clock controller generates and supplies clock to various controllers
within the Exynos4 SoC. The clock binding described here is applicable to all
SoC's in the Exynos4 family.

Required Properties:

- compatible: should be one of the following.
  - "samsung,exynos4210-clock" - controller compatible with Exynos4210 SoC.
  - "samsung,exynos4412-clock" - controller compatible with Exynos4412 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.

All available clocks are defined as preprocessor macros in
dt-bindings/clock/exynos4.h header and can be used in device
tree sources.

Example 1: An example of a clock controller node is listed below.

	clock: clock-controller@10030000 {
		compatible = "samsung,exynos4210-clock";
		reg = <0x10030000 0x20000>;
		#clock-cells = <1>;
	};

Example 2: 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' property.

	serial@13820000 {
		compatible = "samsung,exynos4210-uart";
		reg = <0x13820000 0x100>;
		interrupts = <0 54 0>;
		clocks = <&clock CLK_UART2>, <&clock CLK_SCLK_UART2>;
		clock-names = "uart", "clk_uart_baud0";
	};

Exynos4412 SoC contains some additional clocks for FIMC-ISP (Camera ISP)
subsystem. Registers for those clocks are located in the ISP power domain.
Because those registers are also located in a different memory region than
the main clock controller, a separate clock controller has to be defined for
handling them.

Required Properties:

- compatible: should be "samsung,exynos4412-isp-clock".

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

- #clock-cells: should be 1.

- clocks: list of the clock controller input clock identifiers,
  from common clock bindings, should point to CLK_ACLK200 and
  CLK_ACLK400_MCUISP clocks from the main clock controller.

- clock-names: list of the clock controller input clock names,
  as described in clock-bindings.txt, should be "aclk200" and
  "aclk400_mcuisp".

- power-domains: a phandle to ISP power domain node as described by
  generic PM domain bindings.

Example 3: The clock controllers bindings for Exynos4412 SoCs.

	clock: clock-controller@10030000 {
		compatible = "samsung,exynos4412-clock";
		reg = <0x10030000 0x18000>;
		#clock-cells = <1>;
	};

	isp_clock: clock-controller@10048000 {
		compatible = "samsung,exynos4412-isp-clock";
		reg = <0x10048000 0x1000>;
		#clock-cells = <1>;
		power-domains = <&pd_isp>;
		clocks = <&clock CLK_ACLK200>, <&clock CLK_ACLK400_MCUISP>;
		clock-names = "aclk200", "aclk400_mcuisp";
	};