dt-bindings: clock: convert rockchip,rk3288-cru.txt to YAML

* Rockchip RK3288 Clock and Reset Unit

The RK3288 clock controller generates and supplies clock to various

controllers within the SoC and also implements a reset controller for SoC

peripherals.

A revision of this SoC is available: rk3288w. The clock tree is a bit

different so another dt-compatible is available. Noticed that it is only

setting the difference but there is no automatic revision detection. This

should be performed by bootloaders.

Required Properties:

- compatible: should be "rockchip,rk3288-cru" or "rockchip,rk3288w-cru" in

  case of this revision of Rockchip rk3288.

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

  region.

- #clock-cells: should be 1.

- #reset-cells: should be 1.

Optional Properties:

- rockchip,grf: phandle to the syscon managing the "general register files"

  If missing pll rates are not changeable, due to the missing pll lock status.

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 the dt-bindings/clock/rk3288-cru.h headers and can be

used in device tree sources. Similar macros exist for the reset sources in

these files.

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:

 - "xin24m" - crystal input - required,

 - "xin32k" - rtc clock - optional,

 - "ext_i2s" - external I2S clock - optional,

 - "ext_hsadc" - external HSADC clock - optional,

 - "ext_edp_24m" - external display port clock - optional,

 - "ext_vip" - external VIP clock - optional,

 - "ext_isp" - external ISP clock - optional,

 - "ext_jtag" - external JTAG clock - optional

Example: Clock controller node:

	cru: cru@20000000 {

		compatible = "rockchip,rk3188-cru";

		reg = <0x20000000 0x1000>;

		rockchip,grf = <&grf>;

		#clock-cells = <1>;

		#reset-cells = <1>;

	};

Example: UART controller node that consumes the clock generated by the clock

  controller:

	uart0: serial@10124000 {

		compatible = "snps,dw-apb-uart";

		reg = <0x10124000 0x400>;

		interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;

		reg-shift = <2>;

		reg-io-width = <1>;

		clocks = <&cru SCLK_UART0>;

	};

# SPDX-License-Identifier: GPL-2.0

%YAML 1.2

---

$id: http://devicetree.org/schemas/clock/rockchip,rk3288-cru.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Rockchip RK3288 Clock and Reset Unit (CRU)

maintainers:

  - Elaine Zhang <zhangqing@rock-chips.com>

  - Heiko Stuebner <heiko@sntech.de>

description: |

  The RK3288 clock controller generates and supplies clocks to various

  controllers within the SoC and also implements a reset controller for SoC

  peripherals.

  A revision of this SoC is available: rk3288w. The clock tree is a bit

  different so another dt-compatible is available. Noticed that it is only

  setting the difference but there is no automatic revision detection. This

  should be performed by boot loaders.

  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 the dt-bindings/clock/rk3288-cru.h headers and can be

  used in device tree sources. Similar macros exist for the reset sources in

  these files.

  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:

    - "xin24m"      - crystal input               - required,

    - "xin32k"      - rtc clock                   - optional,

    - "ext_i2s"     - external I2S clock          - optional,

    - "ext_hsadc"   - external HSADC clock        - optional,

    - "ext_edp_24m" - external display port clock - optional,

    - "ext_vip"     - external VIP clock          - optional,

    - "ext_isp"     - external ISP clock          - optional,

    - "ext_jtag"    - external JTAG clock         - optional

properties:

  compatible:

    enum:

      - rockchip,rk3288-cru

      - rockchip,rk3288w-cru

  reg:

    maxItems: 1

  "#clock-cells":

    const: 1

  "#reset-cells":

    const: 1

  clocks:

    maxItems: 1

  clock-names:

    const: xin24m

  rockchip,grf:

    $ref: /schemas/types.yaml#/definitions/phandle

    description:

      Phandle to the syscon managing the "general register files" (GRF),

      if missing pll rates are not changeable, due to the missing pll

      lock status.

required:

  - compatible

  - reg

  - "#clock-cells"

  - "#reset-cells"

additionalProperties: false

examples:

  - |

    cru: clock-controller@ff760000 {

      compatible = "rockchip,rk3288-cru";

      reg = <0xff760000 0x1000>;

      rockchip,grf = <&grf>;

      #clock-cells = <1>;

      #reset-cells = <1>;

    };