Re: [PATCH 5/6] dt-bindings: clock: Document Exynos850 CMU bindings

[Sam Protsenko]

On Wed, 15 Sept 2021 at 11:28, Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxxxxx> wrote:
>
> On 14/09/2021 17:56, Sam Protsenko wrote:
> > Provide dt-schema documentation for Exynos850 SoC clock controller.
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> > ---
> >  .../clock/samsung,exynos850-clock.yaml        | 190 ++++++++++++++++++
> >  1 file changed, 190 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml b/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
> > new file mode 100644
> > index 000000000000..b69ba4125421
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
> > @@ -0,0 +1,190 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/clock/samsung,exynos850-clock.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Samsung Exynos850 SoC clock controller
> > +
> > +maintainers:
> > +  - Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> > +  - Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> > +  - Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx>
> > +  - Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> > +  - Tomasz Figa <tomasz.figa@xxxxxxxxx>
> > +
> > +description: |
> > +  Exynos850 clock controller is comprised of several CMU units, generating
> > +  clocks for different domains. Those CMU units are modeled as separate device
> > +  tree nodes, and might depend on each other. Root clocks in that clock tree are
> > +  two external clocks:: OSCCLK (26 MHz) and RTCCLK (32768 Hz). Those external
> > +  clocks must be defined as fixed-rate clocks in dts.
> > +
> > +  CMU_TOP is a top-level CMU, where all base clocks are prepared using PLLs and
> > +  dividers; all other leaf clocks (other CMUs) are usually derived from CMU_TOP.
> > +
> > +  Each clock is assigned an identifier and client nodes can use this identifier
> > +  to specify the clock which they consume. All clocks that available for usage
> > +  in clock consumer nodes are defined as preprocessor macros in
> > +  'dt-bindings/clock/exynos850.h' header.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - samsung,exynos850-cmu-top
> > +      - samsung,exynos850-cmu-core
> > +      - samsung,exynos850-cmu-hsi
> > +      - samsung,exynos850-cmu-peri
> > +
> > +  clocks:
> > +    minItems: 1
> > +    maxItems: 5
> > +
> > +  clock-names:
> > +    minItems: 1
> > +    maxItems: 5
> > +
> > +  "#clock-cells":
> > +    const: 1
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +allOf:
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: samsung,exynos850-cmu-top
> > +
> > +    then:
> > +      properties:
> > +        clocks:
> > +          items:
> > +            - description: External reference clock (26 MHz)
> > +
> > +        clock-names:
> > +          items:
> > +            - const: oscclk
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: samsung,exynos850-cmu-core
> > +
> > +    then:
> > +      properties:
> > +        clocks:
> > +          items:
> > +            - description: External reference clock (26 MHz)
> > +            - description: CMU_CORE bus clock (from CMU_TOP)
> > +            - description: CCI clock (from CMU_TOP)
> > +            - description: eMMC clock (from CMU_TOP)
> > +            - description: SSS clock (from CMU_TOP)
> > +
> > +        clock-names:
> > +          items:
> > +            - const: oscclk
> > +            - const: dout_core_bus
> > +            - const: dout_core_cci
> > +            - const: dout_core_mmc_embd
> > +            - const: dout_core_sss
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: samsung,exynos850-cmu-hsi
> > +
> > +    then:
> > +      properties:
> > +        clocks:
> > +          items:
> > +            - description: External reference clock (26 MHz)
> > +            - description: External RTC clock (32768 Hz)
> > +            - description: CMU_HSI bus clock (from CMU_TOP)
> > +            - description: SD card clock (from CMU_TOP)
> > +            - description: "USB 2.0 DRD clock (from CMU_TOP)"
> > +
> > +        clock-names:
> > +          items:
> > +            - const: oscclk
> > +            - const: rtcclk
> > +            - const: dout_hsi_bus
> > +            - const: dout_hsi_mmc_card
> > +            - const: dout_hsi_usb20drd
> > +
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: samsung,exynos850-cmu-peri
> > +
> > +    then:
> > +      properties:
> > +        clocks:
> > +          items:
> > +            - description: External reference clock (26 MHz)
> > +            - description: CMU_PERI bus clock (from CMU_TOP)
> > +            - description: UART clock (from CMU_TOP)
> > +            - description: Parent clock for HSI2C and SPI (from CMU_TOP)
> > +
> > +        clock-names:
> > +          items:
> > +            - const: oscclk
> > +            - const: dout_peri_bus
> > +            - const: dout_peri_uart
> > +            - const: dout_peri_ip
> > +
> > +required:
> > +  - compatible
> > +  - "#clock-cells"
> > +  - clocks
> > +  - clock-names
> > +  - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  # Clock controller node for CMU_PERI
> > +  - |
> > +    #include <dt-bindings/clock/exynos850.h>
> > +
> > +    cmu_peri: clock-controller@10030000 {
> > +        compatible = "samsung,exynos850-cmu-peri";
> > +        reg = <0x10030000 0x8000>;
> > +        #clock-cells = <1>;
> > +
> > +        clocks = <&oscclk>, <&cmu_top DOUT_PERI_BUS>,
> > +                 <&cmu_top DOUT_PERI_UART>,
> > +                 <&cmu_top DOUT_PERI_IP>;
> > +        clock-names = "oscclk", "dout_peri_bus",
> > +                      "dout_peri_uart", "dout_peri_ip";
> > +    };
> > +
> > +  # External reference clock (should be provided in particular board DTS)
> > +  - |
> > +    oscclk: clock-oscclk {
> > +        compatible = "fixed-clock";
> > +        #clock-cells = <0>;
> > +        clock-output-names = "oscclk";
> > +        clock-frequency = <26000000>;
> > +    };
>
> Skip ossclk - it's trivial and not related to these bindings.
>
> > +
> > +  # UART controller node that consumes the clock generated by CMU_PERI
> > +  - |
> > +    #include <dt-bindings/clock/exynos850.h>
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > +    serial_0: serial@13820000 {
> > +        compatible = "samsung,exynos850-uart";
> > +        reg = <0x13820000 0x100>;
> > +        interrupts = <GIC_SPI 227 IRQ_TYPE_LEVEL_HIGH>;
> > +        pinctrl-names = "default";
> > +        pinctrl-0 = <&uart0_pins>;
> > +        clocks = <&cmu_peri GOUT_UART_PCLK>, <&cmu_peri GOUT_UART_IPCLK>;
> > +        clock-names = "uart", "clk_uart_baud0";
>
> The same, skip it because it is trivial and common with all clock providers.
>

Sure, will do in v2.

> Also Rob's robot checker complains about it.
>
> Best regards,
> Krzysztof