Re: [PATCH RFC 1/2] dt-bindings: pinctrl: Add pinctrl-packed

Krzysztof Kozlowski
2026-02-13T09:57:32Z

On 13/02/2026 09:17, Billy Tsai wrote:
> Add a Devicetree binding for a generic pin controller where pinmux and/or
> pin configuration are represented as fixed-width fields packed
> sequentially within shared registers.
>
> The binding targets controllers that are typically exposed as subnodes of
> a syscon node and accessed via regmap-mmio through the parent.
>
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> ---
> .../bindings/pinctrl/pinctrl-packed.yaml | 166 +++++++++++++++++++++
> 1 file changed, 166 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-packed.yaml b/Documentation/devicetree/bindings/pinctrl/pinctrl-packed.yaml
> new file mode 100644
> index 000000000000..dd01ba2fed71
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-packed.yaml
> @@ -0,0 +1,166 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pinctrl/pinctrl-packed.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic Pin Controller with Packed-Field Registers
> +
> +maintainers:
> + - Billy Tsai <billy_tsai@aspeedtech.com>
> +
> +description:
> + This binding describes pin controller hardware where pinmux and/or
> + pin configuration fields are represented as fixed-width fields packed
> + sequentially within shared registers.
> +
> + Such controllers are commonly embedded within a larger system control
> + unit (SCU) register block and may be exposed as subnodes of a syscon
> + device.
> +
> + Conceptually, this model is related to the pinctrl-single binding,
> + but instead of describing individual register offsets via
> + <offset, value, mask> tuples, the hardware provides fixed-width,
> + per-pin fields packed linearly within shared registers.

Why this cannot be part of pinctrl-single then? Why all these properties
are needed? I imagine that you need them to customize the generic
binding to your device and that would be counter argument - generic
bindings are too generic so people need to grow them with hundreds
properties (see the very simple binding of simple audio card).

> +
> +properties:
> + compatible:
> + oneOf:

Drop oneOf

> + - enum:
> + - pinctrl-packed
> + - pinconf-packed
> +
> + reg:
> + maxItems: 1
> +
> + '#pinctrl-cells':
> + description:
> + The pinctrl provider uses standard state nodes referenced by pinctrl-N
> + properties; consumers do not pass per-pin arguments via phandle.
> + const: 1
> +
> + pinctrl-packed,function-mask:
> + description: Mask of the allowed register bits for a single pin.
> + $ref: /schemas/types.yaml#/definitions/uint32
> +
> + pinctrl-packed,gpio-range:
> + description: Optional list of pin base, nr pins & gpio function.
> + $ref: /schemas/types.yaml#/definitions/phandle-array
> + items:
> + items:
> + - description: phandle of a gpio-range node
> + - description: pin base
> + - description: number of pins
> + - description: gpio function
> +
> +patternProperties:
> + '-pins(-[0-9]+)?$|-pin$':
> + type: object
> + additionalProperties: false
> +
> + properties:
> + pinctrl-packed,pins:

No, use standard pinctrl properties.

> + description: Array of pin index and function selector pairs.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> +
> + pinctrl-packed,bias-pullup:
> + description: Optional bias pull-up configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 4
> + items:
> + - description: Input value.
> + - description: Enabled pull-up bits.
> + - description: Disabled pull-up bits.
> + - description: Pull-up mask.
> + additionalItems: false
> +
> + pinctrl-packed,bias-pulldown:
> + description: Optional bias pull-down configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 4
> + items:
> + - description: Input value.
> + - description: Enabled pull-down bits.
> + - description: Disabled pull-down bits.
> + - description: Pull-down mask.
> + additionalItems: false
> +
> + pinctrl-packed,drive-strength:
> + description: Optional drive strength configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 2
> + items:
> + - description: Drive strength value.
> + - description: Drive strength mask.
> + additionalItems: false
> +
> + pinctrl-packed,input-schmitt:
> + description: Optional input Schmitt trigger configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 2
> + items:
> + - description: Schmitt trigger value.
> + - description: Schmitt trigger mask.
> + additionalItems: false
> +
> + pinctrl-packed,input-schmitt-enable:
> + description: Optional input Schmitt enable configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 4
> + items:
> + - description: Input value.
> + - description: Enable bits.
> + - description: Disable bits.
> + - description: Schmitt mask.
> + additionalItems: false
> +
> + pinctrl-packed,low-power-mode:
> + description: Optional low power mode configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 2
> + items:
> + - description: Low power value.
> + - description: Low power mask.
> + additionalItems: false
> +
> + pinctrl-packed,slew-rate:
> + description: Optional slew rate configuration.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + maxItems: 2
> + items:
> + - description: Slew rate value.
> + - description: Slew rate mask.
> + additionalItems: false
> +
> +required:
> + - compatible
> + - reg
> + - "#pinctrl-cells"
> + - pinctrl-packed,function-mask
> +
> +additionalProperties: false
> +
> +allOf:
> + - $ref: pinctrl.yaml#
> +
> +examples:
> + - |
> + syscon@0 {
> + compatible = "syscon", "simple-mfd";

This is not allowed and you will have warnings here, which means you did
not test the binding correctly (completely). Not even needed here, drop
entire node.

Best regards,
Krzysztof