Re: [PATCH v2 1/2] dt-bindings: gpio: Add Axiado SGPIO controller

[Krzysztof Kozlowski <krzk@kernel.org>]

On 29/07/2026 09:02, Petar Stepanovic wrote:
> +description: |
> +  The Axiado SGPIO controller provides a serial GPIO expansion interface
> +  that multiplexes multiple GPIO signals over a small set of physical lines.
> +
> +  The controller operates as a shift-based interface, where output values
> +  are serialized on a data output line and input values are sampled from a
> +  data input line in synchronization with a shift clock. A latch signal is
> +  used to update output states after each transfer cycle.
> +
> +  The interface uses data output (DOUT), data input (DIN), shift clock
> +  (SCLK), and latch signal (LATCH).
> +
> +  Each SGPIO position provides one fixed-direction input GPIO and one
> +  fixed-direction output GPIO. Input GPIOs support edge-triggered
> +  interrupts.
> +
> +  GPIOs are organized in banks of 32 signals, with registers controlling
> +  output values, input sampling, and interrupt status. The number of GPIO
> +  lines depends on the hardware variant.
> +
> +  The controller detects changes on input GPIOs. Interrupt events are
> +  aggregated and signaled through a single interrupt line to the parent
> +  interrupt controller.
> +
> +  Register access is performed over the APB bus. The SGPIO shift clock is
> +  derived from the APB clock using a programmable divider.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - axiado,ax3000-sgpio
> +      - axiado,ax3005-sgpio
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    description:
> +      APB clock used for register access and SGPIO shift clock generation
> +    maxItems: 1
> +
> +  bus-frequency:
> +    description: SGPIO shift clock frequency in Hz
> +    minimum: 1

Such property is not allowed. Why you cannot calculate it automatically?

> +
> +  gpio-controller: true
> +
> +  '#gpio-cells':
> +    const: 2
> +
> +  interrupt-controller: true
> +
> +  '#interrupt-cells':
> +    const: 2
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  ngpios:
> +    description:
> +      Number of SGPIO positions. Each position provides one input GPIO and
> +      one output GPIO.
> +    enum: [128, 512]
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          const: axiado,ax3000-sgpio
> +    then:
> +      properties:
> +        ngpios:
> +          const: 128

else what? 3005 has 512? Then these are implied by compatible, no?

> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - bus-frequency
> +  - gpio-controller
> +  - '#gpio-cells'
> +  - interrupt-controller
> +  - '#interrupt-cells'
> +  - interrupts
> +  - ngpios
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    sgpio@a000 {

git grep sgpio@

No results (except well known poor coding style platform). I already
commented on this.

> +        compatible = "axiado,ax3005-sgpio";
> +        reg = <0xa000 0x800>;
> +        clocks = <&apb_clk>;
> +        bus-frequency = <1000000>;
> +        gpio-controller;
Best regards,
Krzysztof