xref: /linux/Documentation/devicetree/bindings/clock/ti/ti,mux-clock.yaml (revision 9f3a2ba62c7226a6604b8aaeb92b5ff906fa4e6b)

# SPDX-License-Identifier: GPL-2.0-only
%YAML 1.2
---
$id: http://devicetree.org/schemas/clock/ti/ti,mux-clock.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Texas Instruments mux clock

maintainers:
  - Tero Kristo <kristo@kernel.org>

description: |
  This clock assumes a register-mapped multiplexer with multiple inpt clock
  signals or parents, one of which can be selected as output. This clock does
  not gate or adjust the parent rate via a divider or multiplier.

  By default the "clocks" property lists the parents in the same order
  as they are programmed into the register.  E.g:

    clocks = <&foo_clock>, <&bar_clock>, <&baz_clock>;

  Results in programming the register as follows:

  register value   selected parent clock
  0                foo_clock
  1                bar_clock
  2                baz_clock

  Some clock controller IPs do not allow a value of zero to be programmed
  into the register, instead indexing begins at 1.  The optional property
  "index-starts-at-one" modified the scheme as follows:

  register value   selected clock parent
  1                foo_clock
  2                bar_clock
  3                baz_clock

  The binding must provide the register to control the mux. Optionally
  the number of bits to shift the control field in the register can be
  supplied. If the shift value is missing it is the same as supplying
  a zero shift.

properties:
  compatible:
    enum:
      - ti,mux-clock
      - ti,composite-mux-clock

  "#clock-cells":
    const: 0

  clocks: true

  clock-output-names:
    maxItems: 1

  reg:
    maxItems: 1

  ti,bit-shift:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      Number of bits to shift the bit-mask
    maximum: 31
    default: 0

  ti,index-starts-at-one:
    type: boolean
    description:
      Valid input select programming starts at 1, not zero

  ti,set-rate-parent:
    type: boolean
    description:
      clk_set_rate is propagated to parent clock,
      not supported by the composite-mux-clock subtype.

  ti,latch-bit:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      Latch the mux value to HW, only needed if the register
      access requires this. As an example, dra7x DPLL_GMAC H14 muxing
      implements such behavior.
    maximum: 31

if:
  properties:
    compatible:
      contains:
        const: ti,composite-mux-clock
then:
  properties:
    ti,set-rate-parent: false

required:
  - compatible
  - "#clock-cells"
  - clocks
  - reg

additionalProperties: false

examples:
  - |
    bus {
      #address-cells = <1>;
      #size-cells = <0>;

      clock-controller@110 {
        compatible = "ti,mux-clock";
        reg = <0x0110>;
        #clock-cells = <0>;
        clocks = <&virt_12000000_ck>, <&virt_13000000_ck>, <&virt_16800000_ck>;
        ti,index-starts-at-one;
        ti,set-rate-parent;
      };

      clock-controller@120 {
        compatible = "ti,composite-mux-clock";
        reg = <0x0120>;
        #clock-cells = <0>;
        clocks = <&core_96m_fck>, <&mcbsp_clks>;
        ti,bit-shift = <4>;
      };
    };