Re: [PATCH v1 1/8] dt-bindings: pinctrl: Add thead,th1520-pinctrl bindings

[Rob Herring <robh@kernel.org>]

On Fri, Dec 15, 2023 at 03:38:59PM +0100, Emil Renner Berthing wrote:
> Add bindings for the pin controllers on the T-Head TH1520 RISC-V SoC.
> 
> Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
> ---
>  .../pinctrl/thead,th1520-pinctrl.yaml         | 156 ++++++++++++++++++
>  1 file changed, 156 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
> new file mode 100644
> index 000000000000..1b1b446cd498
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
> @@ -0,0 +1,156 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pinctrl/thead,th1520-pinctrl.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: T-Head TH1520 SoC pin controller
> +
> +maintainers:
> +  - Emil Renner Berthing <emil.renner.berthing@canonical.com>
> +
> +description: |
> +  Pinmux and pinconf controller in the T-Head TH1520 RISC-V SoC.
> +
> +  The TH1520 has 3 groups of pads each controlled from different memory ranges.
> +  Confusingly the memory ranges are named
> +    PADCTRL_AOSYS  -> PAD Group 1
> +    PADCTRL1_APSYS -> PAD Group 2
> +    PADCTRL0_APSYS -> PAD Group 3

Are the programming models different?

> +
> +  Each pad can be muxed individually to up to 5 different functions. For most
> +  pads only a few of those 5 configurations are valid though, and a few pads in
> +  group 1 does not support muxing at all.
> +
> +  Pinconf is fairly regular except for a few pads in group 1 that either can't
> +  be configured or has some special functions. The rest have configurable drive
> +  strength, input enable, schmitt trigger, slew rate, pull-up and pull-down in
> +  addition to a special strong pull up.
> +
> +  Certain pads in group 1 can be muxed to AUDIO_PA0 - AUDIO_PA30 functions and
> +  are then meant to be used by the audio co-processor. Each such pad can then
> +  be further muxed to either audio GPIO or one of 4 functions such as UART, I2C
> +  and I2S. If the audio pad is muxed to one of the 4 functions then pinconf is
> +  also configured in different registers. All of this is done from a different
> +  AUDIO_IOCTRL memory range and is left to the audio co-processor for now.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - thead,th1520-group1-pinctrl
> +      - thead,th1520-group2-pinctrl
> +      - thead,th1520-group3-pinctrl
> +
> +  reg:
> +    maxItems: 1
> +
> +patternProperties:
> +  '-[0-9]+$':

Please make this a bit more specific. "-grp-[0-9]+$"?

> +    type: object

blank line. And move additionalProperties here. Easier to read in the 
indented cases.

> +    patternProperties:
> +      '-pins$':
> +        type: object
> +        $ref: /schemas/pinctrl/pincfg-node.yaml
> +        description:
> +          A pinctrl node should contain at least one subnode describing one
> +          or more pads and their associated pinmux and pinconf settings.
> +
> +        properties:
> +          pins:
> +            $ref: /schemas/types.yaml#/definitions/string-array

Type is defined in pinmux-node.yaml. You need to reference it and drop 
this.

Normally the possible values are listed out.

> +            description: List of pads that properties in the node apply to.
> +
> +          function:
> +            $ref: /schemas/types.yaml#/definitions/string
> +            enum: [ "0", "1", "2", "3", "4", "5" ]
> +            description: The mux function to select for the given pins.
> +
> +          bias-disable: true
> +
> +          bias-pull-up:
> +            type: boolean
> +
> +          bias-pull-down:
> +            type: boolean
> +
> +          drive-strength:
> +            enum: [ 1, 2, 3, 5, 7, 8, 10, 12, 13, 15, 16, 18, 20, 21, 23, 25 ]
> +
> +          input-enable: true
> +
> +          input-disable: true
> +
> +          input-schmitt-enable: true
> +
> +          input-schmitt-disable: true
> +
> +          slew-rate:
> +            maximum: 1
> +
> +          thead,strong-pull-up:
> +            oneOf:
> +              - type: boolean
> +              - $ref: /schemas/types.yaml#/definitions/uint32
> +                enum: [ 0, 2100 ]
> +            description: Enable or disable strong 2.1kOhm pull-up.

bias-pull-up can already specify the strength in Ohms.

> +
> +        required:
> +          - pins
> +
> +        additionalProperties: false
> +
> +    additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    padctrl0_apsys: pinctrl@ec007000 {
> +        compatible = "thead,th1520-group3-pinctrl";
> +        reg = <0xec007000 0x1000>;
> +
> +        uart0_pins: uart0-0 {
> +            tx-pins {
> +                pins = "UART0_TXD";
> +                function = "0";
> +                bias-disable;
> +                drive-strength = <3>;
> +                input-disable;
> +                input-schmitt-disable;
> +                slew-rate = <0>;
> +            };
> +
> +            rx-pins {
> +                pins = "UART0_RXD";
> +                function = "0";
> +                bias-disable;
> +                drive-strength = <1>;
> +                input-enable;
> +                input-schmitt-enable;
> +                slew-rate = <0>;
> +            };
> +        };
> +    };
> +
> +    padctrl1_apsys: pinctrl@e7f3c000 {
> +        compatible = "thead,th1520-group2-pinctrl";
> +        reg = <0xe7f3c000 0x1000>;
> +
> +        i2c5_pins: i2c5-0 {
> +            i2c-pins {
> +                pins = "QSPI1_CSN0",    /* I2C5_SCL */
> +                       "QSPI1_D0_MOSI"; /* I2C5_SDA */
> +                function = "2";
> +                bias-disable;
> +                drive-strength = <7>;
> +                input-enable;
> +                input-schmitt-enable;
> +                slew-rate = <0>;
> +                thead,strong-pull-up;
> +            };
> +        };
> +    };
> -- 
> 2.40.1
>