Re: [PATCH v2 02/14] dt-bindings: pinctrl: Add RaspberryPi RP1 gpio/pinctrl/pinmux bindings

[Andrea della Porta <andrea.porta@suse.com>]

Hi Krzysztof,

On 08:29 Tue 08 Oct     , Krzysztof Kozlowski wrote:
> On Mon, Oct 07, 2024 at 02:39:45PM +0200, Andrea della Porta wrote:
> > Add device tree bindings for the gpio/pin/mux controller that is part of
> > the RP1 multi function device, and relative entries in MAINTAINERS file.
> > 
> > Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
> > ---
> >  .../pinctrl/raspberrypi,rp1-gpio.yaml         | 169 ++++++++++++++++++
> >  MAINTAINERS                                   |   2 +
> >  2 files changed, 171 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml b/Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml
> > new file mode 100644
> > index 000000000000..46e071ec6251
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml
> > @@ -0,0 +1,169 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/pinctrl/raspberrypi,rp1-gpio.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: RaspberryPi RP1 GPIO/Pinconf/Pinmux Controller submodule
> > +
> > +maintainers:
> > +  - Andrea della Porta <andrea.porta@suse.com>
> > +
> > +description:
> > +  The RP1 chipset is a Multi Function Device containing, among other sub-peripherals,
> > +  a gpio/pinconf/mux controller whose 54 pins are grouped into 3 banks. It works also
> > +  as an interrupt controller for those gpios.
> > +
> > +  Each pin configuration node lists the pin(s) to which it applies, and one or
> > +  more of the mux function to select on those pin(s), and their configuration.
> > +  The pin configuration and multiplexing supports the generic bindings.
> > +  For details on each properties (including the meaning of "pin configuration node"),
> > +  you can refer to ./pinctrl-bindings.txt.
> 
> Drop the sentence. pinctrl.yaml defines this already.

Just to be sure, by 'sentence' I assume you mean the entire paragraph from
"Each pin configuration..." to "...refer to ./pinctrl-bindings.txt.", right?
 
> 
> > +
> > +properties:
> > +  compatible:
> > +    const: raspberrypi,rp1-gpio
> > +
> > +  reg:
> > +    maxItems: 3
> > +    description: One reg specifier for each one of the 3 pin banks.
> > +
> > +  '#gpio-cells':
> > +    description: The first cell is the pin number and the second cell is used
> > +      to specify the flags (see include/dt-bindings/gpio/gpio.h).
> > +    const: 2
> > +
> > +  gpio-controller: true
> > +
> > +  gpio-ranges:
> > +    maxItems: 1
> > +
> > +  gpio-line-names:
> > +    maxItems: 54
> > +
> > +  interrupts:
> > +    maxItems: 3
> > +    description: One interrupt specifier for each one of the 3 pin banks.
> > +
> > +  '#interrupt-cells':
> > +    description:
> > +      Specifies the Bank number [0, 1, 2] and Flags as defined in
> > +      include/dt-bindings/interrupt-controller/irq.h.
> > +    const: 2
> > +
> > +  interrupt-controller: true
> > +
> > +additionalProperties:
> > +  anyOf:
> 
> Uh, no, I think you got comments on this. You should be specific which
> nodes you expect, e.g. pins or groups. See other recent bindings for
> example.

Please see below.

> 
> > +    - type: object
> > +      additionalProperties: false
> > +      allOf:
> > +        - $ref: pincfg-node.yaml#
> > +        - $ref: pinmux-node.yaml#
> > +
> > +      description:
> > +        Pin controller client devices use pin configuration subnodes (children
> > +        and grandchildren) for desired pin configuration.
> > +        Client device subnodes use below standard properties.
> > +
> > +      properties:
> > +        pins:
> > +          description:
> > +            A string (or list of strings) adhering to the pattern "gpio[0-5][0-9]"
> > +        function: true
> > +        bias-disable: true
> > +        bias-pull-down: true
> > +        bias-pull-up: true
> > +        slew-rate:
> > +          description: 0 is slow slew rate, 1 is fast slew rate
> > +          enum: [ 0, 1 ]
> > +        drive-strength:
> > +          enum: [ 2, 4, 8, 12 ]
> > +
> > +    - type: object
> > +      additionalProperties:
> > +        $ref: "#/additionalProperties/anyOf/0"
> 
> I don't quite get what you wanted to achieve here.

This should be a compact way to describe a schema that allows declarations like
the following:

rp1_gpio {
  ...

  /* grouped gpios */
  rp1_uart0_14_15: rp1_uart0_14_15 {
    pin_txd {
      function = "uart0";
      pins = "gpio14";
      bias-disable;
    };

    pin_rxd {
      function = "uart0";
      pins = "gpio15";
      bias-pull-up;
    };
  };

  /* standalone pins */
  rp1_i2s0_18_21: rp1_i2s0_18_21 {
      function = "i2s0";
      pins = "gpio18", "gpio19", "gpio20", "gpio21";
      bias-disable;
  };

  ...
};

that is, both standalone and group pinctrl/pinmux node.

> 
> > +
> > +allOf:
> > +  - $ref: pinctrl.yaml#
> > +
> > +required:
> > +  - reg
> > +  - compatible
> > +  - "#gpio-cells"
> > +  - gpio-controller
> > +  - interrupts
> > +  - "#interrupt-cells"
> > +  - interrupt-controller
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > +    rp1 {
> > +        #address-cells = <2>;
> > +        #size-cells = <2>;
> > +
> > +        rp1_gpio: pinctrl@c0400d0000 {
> > +            reg = <0xc0 0x400d0000  0x0 0xc000>,
> > +                  <0xc0 0x400e0000  0x0 0xc000>,
> > +                  <0xc0 0x400f0000  0x0 0xc000>;
> > +            compatible = "raspberrypi,rp1-gpio";
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            interrupt-controller;
> > +            #interrupt-cells = <2>;
> > +            interrupts = <0 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <1 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <2 IRQ_TYPE_LEVEL_HIGH>;
> > +            gpio-line-names =
> > +                   "ID_SDA", // GPIO0
> > +                   "ID_SCL", // GPIO1
> > +                   "GPIO2", "GPIO3", "GPIO4", "GPIO5", "GPIO6",
> > +                   "GPIO7", "GPIO8", "GPIO9", "GPIO10", "GPIO11",
> > +                   "GPIO12", "GPIO13", "GPIO14", "GPIO15", "GPIO16",
> > +                   "GPIO17", "GPIO18", "GPIO19", "GPIO20", "GPIO21",
> > +                   "GPIO22", "GPIO23", "GPIO24", "GPIO25", "GPIO26",
> > +                   "GPIO27",
> > +                   "PCIE_RP1_WAKE", // GPIO28
> > +                   "FAN_TACH", // GPIO29
> > +                   "HOST_SDA", // GPIO30
> > +                   "HOST_SCL", // GPIO31
> > +                   "ETH_RST_N", // GPIO32
> > +                   "", // GPIO33
> > +                   "CD0_IO0_MICCLK", // GPIO34
> > +                   "CD0_IO0_MICDAT0", // GPIO35
> > +                   "RP1_PCIE_CLKREQ_N", // GPIO36
> > +                   "", // GPIO37
> > +                   "CD0_SDA", // GPIO38
> > +                   "CD0_SCL", // GPIO39
> > +                   "CD1_SDA", // GPIO40
> > +                   "CD1_SCL", // GPIO41
> > +                   "USB_VBUS_EN", // GPIO42
> > +                   "USB_OC_N", // GPIO43
> > +                   "RP1_STAT_LED", // GPIO44
> > +                   "FAN_PWM", // GPIO45
> > +                   "CD1_IO0_MICCLK", // GPIO46
> > +                   "2712_WAKE", // GPIO47
> > +                   "CD1_IO1_MICDAT1", // GPIO48
> > +                   "EN_MAX_USB_CUR", // GPIO49
> > +                   "", // GPIO50
> > +                   "", // GPIO51
> > +                   "", // GPIO52
> > +                   ""; // GPIO53
> > +
> > +            rp1_uart0_14_15: rp1_uart0_14_15 {
> 
> Underscores are not allowed in node names. Please read DTS coding style.
> 
> Drop unused labels.

Ack.

Many thanks,
Andrea

> 
> > +                pin_txd {
> > +                    function = "uart0";
> > +                    pins = "gpio14";
> > +                    bias-disable;
> > +                };
> 
> Best regards,
> Krzysztof
>