Re: [PATCH RFC 1/2] dt-bindings: pinctrl: Add pinctrl-packed
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2026-02-13 09:57:26
Also in:
linux-aspeed, linux-devicetree, linux-gpio, lkml
On 13/02/2026 09:17, Billy Tsai wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- .../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