Re: [PATCH v3 02/12] dt-bindings: pinctrl: Add RaspberryPi RP1 gpio/pinctrl/pinmux bindings

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

Hi Krzysztof,

On 08:26 Tue 29 Oct     , Krzysztof Kozlowski wrote:
> On Mon, Oct 28, 2024 at 03:07:19PM +0100, 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         | 163 ++++++++++++++++++
> >  MAINTAINERS                                   |   2 +
> >  2 files changed, 165 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..465a53a6d84f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml
> > @@ -0,0 +1,163 @@
> > +# 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
> 
> Please wrap code according to coding style (checkpatch is not a coding
> style description but only a tool).

Ack.

> 
> > +  as an interrupt controller for those gpios.
> > +
> > +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:
> 
> Not much improved. You are supposed to have here pattern, just like
> other bindings. I asked for this last time.
> 
> And there are examples using it - almost all or most of pinctrl
> bindings, including bindings having subnodes (but you do not use such
> case here).

This is the same approach used in [1], which seems quite recent. I did't
use pattern because I wouldn't really want to enforce a particular naming
scheme. Subnodes are used, please see below. Since pinctrl.yaml explicitly
says that there is no common binding but each device has its own, I
thought that was reasonable choice. Should I enforce some common pattern,
then?

> 
> > +  anyOf:
> > +    - 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"
> 
> Your example does not use any subnodes, so this looks not needed.

The example has subnodes, as in the following excerpt from the example:

            rp1-uart0-14-15 {
                pin_txd {
                    function = "uart0";
                    pins = "gpio14";
                    bias-disable;
                };

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

Many thanks,
Andrea

[1] - Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml

> 
> Best regards,
> Krzysztof
>