Re: [PATCH v2 2/3] dt-bindings: clock: add TI CDCE6214 binding

[Krzysztof Kozlowski <krzk@kernel.org>]

On 09/04/2025 13:20, Sascha Hauer wrote:
> The CDCE6214 is a Ultra-Low Power Clock Generator With One PLL, Four
> Differential Outputs, Two Inputs, and Internal EEPROM. This patch adds
> the device tree binding for this chip.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  .../devicetree/bindings/clock/ti,cdce6214.yaml     | 167 +++++++++++++++++++++
>  include/dt-bindings/clock/ti,cdce6214.h            |  24 +++
>  2 files changed, 191 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/ti,cdce6214.yaml b/Documentation/devicetree/bindings/clock/ti,cdce6214.yaml
> new file mode 100644
> index 0000000000000..957e40403100d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/ti,cdce6214.yaml
> @@ -0,0 +1,167 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/ti,cdce6214.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: TI CDCE6214 programmable clock generator with PLL
> +
> +maintainers:
> +  - Sascha Hauer <s.hauer@pengutronix.de>
> +
> +description:
> +  Ultra-Low Power Clock Generator With One PLL, Four Differential Outputs,
> +  Two Inputs, and Internal EEPROM
> +
> +  https://www.ti.com/product/CDCE6214
> +
> +properties:
> +  compatible:
> +    enum:
> +      - ti,cdce6214
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    minItems: 1
> +    maxItems: 2
> +
> +  clock-names:
> +    minItems: 1
> +    maxItems: 1
> +    items:
> +      enum: [ priref, secref ]
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +  '#clock-cells':
> +    const: 1
> +
> +patternProperties:
> +  '^clk@[0-1]$':
> +    type: object
> +    description:
> +      optional child node that can be used to specify input pin parameters. The reg
> +      properties match the CDCE6214_CLK_* defines.
> +
> +    additionalProperties: false
> +
> +    properties:
> +      reg:
> +        description:
> +          clock input identifier.
> +        minimum: 0
> +        maximum: 1
> +
> +      ti,clkin-fmt:
> +        description: |
> +          Clock input format. Available options are:
> +          0 LVCMOS
> +          1 XTAL
> +          2 Differential
> +        $ref: /schemas/types.yaml#/definitions/uint32

Drop, that's not string. Make it readable for DTS users.

> +        minimum: 0
> +        maximum: 2
> +
> +      ti,xo-cload-femtofarad:
> +        description:
> +          Selects load cap for XO in femto Farad (fF). Up to 9000fF
> +        $ref: /schemas/types.yaml#/definitions/uint32

Drop and use proper unit suffix from property-units in dtschema.


> +        minimum: 3000
> +        maximum: 9000
> +
> +      ti,xo-bias-current-microampere:
> +        description:
> +          Bias current setting of the XO.
> +        $ref: /schemas/types.yaml#/definitions/uint32

Ditto

> +        minimum: 0
> +        maximum: 1758
> +
> +  '^clk@[2-9]$':
> +    type: object
> +    description:
> +      optional child node that can be used to specify output pin parameters.  The reg
> +      properties match the CDCE6214_CLK_* defines.
> +
> +    additionalProperties: false
> +
> +    properties:
> +      reg:
> +        description:
> +          clock output identifier.
> +        minimum: 2
> +        maximum: 9
> +
> +      ti,clkout-fmt:
> +        description: |
> +          Clock input format. Available options are:
> +          0 CMOS
> +          1 LVDS
> +          2 LP-HCSL

Drop these three lines

> +        $ref: /schemas/types.yaml#/definitions/uint32

Drop, this is supposed to be string.
enum: [ cmos, lvds, lp-hcsl ]

> +        minimum: 0
> +        maximum: 2
> +
> +      ti,cmos-mode:
> +        description: |
> +          CMOS output mode. Available options are:
> +          0 disabled
> +          1 high polarity
> +          2 low polarity
> +          first array entry is for the CMOSP pin, second for the CMOSN pin
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        minItems: 2
> +        maxItems: 2
> +        items:
> +          maximum: 2
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - '#clock-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        clock-generator@67 {
> +            compatible = "ti,cdce6214";
> +            reg = <0x67>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            #clock-cells = <1>;
> +            clocks = <&clock_ref25m>;
> +            clock-names = "secref";
> +
> +            clk@1 {
> +                reg = <1>; // CDCE6214_CLK_SECREF
> +                ti,clkin-fmt = <1>; // XTAL
> +            };
> +
> +            clk@3 {
> +                reg = <3>; // CDCE6214_CLK_OUT1
> +                ti,clkout-fmt = <0>; // CMOS
> +                ti,cmos-mode = <1 2>; // CMOSP = highpol, CMOSN = lowpol

Why do you need comments here? If you chosen magic numbers, it means
they are readable by themself. If you need comments, then it is a sign
they are not obvious and just go with the code I asked you - enum string.


Best regards,
Krzysztof