Re: [PATCH 3/3] devicetree: bindings: pinctrl: Add bindings doc for Sunplus SP7021.

[Linus Walleij <linus.walleij@linaro.org>]

Hi Wells Lu,

thanks for your patch!

On Wed, Oct 27, 2021 at 10:55 AM Wells Lu <wellslutw@gmail.com> wrote:

> +      properties:
> +        pins:
> +          description: |
> +            Define pins which are used by pinctrl node's client device.
> +
> +            It consists of one or more integers which represents the config
> +            setting for corresponding pin. Please use macro SPPCTL_IOPAD to
> +            define the integers for pins.
> +
> +            The first argument of the macro is pin number, the second is pin
> +            type, the third is type of GPIO, the last is default output state
> +            of GPIO.
> +          $ref: /schemas/types.yaml#/definitions/uint32-array
> +
> +        function:
> +          description: |
> +            Define pin-function which is used by pinctrl node's client device.
> +            The name should be one of string in the following enumeration.
> +          $ref: "/schemas/types.yaml#/definitions/string"
> +          enum: [ SPI_FLASH, SPI_FLASH_4BIT, SPI_NAND, CARD0_EMMC, SD_CARD,
> +                  UA0, FPGA_IFX, HDMI_TX, LCDIF, USB0_OTG, USB1_OTG ]
> +
> +        groups:
> +          description: |
> +            Define pin-group in a specified pin-function.
> +            The name should be one of string in the following enumeration.
> +          $ref: "/schemas/types.yaml#/definitions/string"
> +          enum: [ SPI_FLASH1, SPI_FLASH2, SPI_FLASH_4BIT1, SPI_FLASH_4BIT2,
> +                  SPI_NAND, CARD0_EMMC, SD_CARD, UA0, FPGA_IFX, HDMI_TX1,
> +                  HDMI_TX2, HDMI_TX3, LCDIF, USB0_OTG, USB1_OTG ]

Is it possible to use
Documentation/devicetree/bindings/pinctrl/pinmux-node.yaml
for this like other drivers do?

> +        zero_func:
> +          description: |
> +            Disabled pins which are not used by pinctrl node's client device.
> +          $ref: /schemas/types.yaml#/definitions/uint32-array

I have never seen this before. Can't you just use pin control hogs
for this so the pin controller just take care of these pins?

> +      allOf:
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - SPI_FLASH
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - SPI_FLASH1
> +                  - SPI_FLASH2
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - SPI_FLASH_4BIT
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - SPI_FLASH_4BIT1
> +                  - SPI_FLASH_4BIT2
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - SPI_NAND
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - SPI_NAND
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - CARD0_EMMC
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - CARD0_EMMC
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - SD_CARD
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - SD_CARD
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - UA0
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - UA0
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - FPGA_IFX
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - FPGA_IFX
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - HDMI_TX
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - HDMI_TX1
> +                  - HDMI_TX2
> +                  - HDMI_TX3
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - LCDIF
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - LCDIF
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - USB0_OTG
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - USB0_OTG
> +        - if:
> +            properties:
> +              function:
> +                enum:
> +                  - USB1_OTG
> +          then:
> +            properties:
> +              groups:
> +                enum:
> +                  - USB1_OTG

This looks complex to me, I need feedback from bindings people
on this.

> +        pins_uart0: pins_uart0 {
> +            function = "UA0";
> +            groups = "UA0";
> +        };
> +
> +        pins_uart1: pins_uart1 {
> +            pins = <
> +                SPPCTL_IOPAD(11,SPPCTL_PCTL_G_PMUX,MUXF_UA1_TX,0)
> +                SPPCTL_IOPAD(10,SPPCTL_PCTL_G_PMUX,MUXF_UA1_RX,0)
> +                SPPCTL_IOPAD(7,SPPCTL_PCTL_G_GPIO,0,SPPCTL_PCTL_L_OUT)
> +            >;
> +        };

This first looks like two ways to do the same thing?
UART0 uses strings for group + function and uart1 control
individual pins.

Is it possible to just do it one way?

I think the pins = <...> scheme includes also multiplexing settings
and then it should be named pinmux = <...>:

Please read
Documentation/devicetree/bindings/pinctrl/pinmux-node.yaml
closely.

Yours,
Linus Walleij