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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/nxp,mc33978.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP MC33978/MC34978 Multiple Switch Detection Interface
+
+maintainers:
+ - David Jander <david@protonic.nl>
+ - Oleksij Rempel <o.rempel@pengutronix.de>
+
+description: |
+ The MC33978 and MC34978 are Multiple Switch Detection Interface (MSDI)
+ devices with 22 switch inputs, integrated fault detection, and analog
+ multiplexer (AMUX) for voltage/temperature monitoring.
+
+ Pin numbering:
+ - Pins 0-13: SG0-SG13 (Switch-to-Ground inputs). These pins monitor
+ contacts closed to ground and typically require GPIO_ACTIVE_LOW
+ flags when used as digital inputs.
+ - Pins 14-21: SP0-SP7 (Programmable inputs). These can be configured
+ as SG (Switch-to-Ground) or SB (Switch-to-Battery) inputs. SB
+ inputs monitor contacts closed to the battery voltage and typically
+ require GPIO_ACTIVE_HIGH flags when used as digital inputs.
+
+ Output Emulation:
+ The hardware lacks standard push-pull output drivers. Outputs are emulated
+ by toggling the programmable wetting current sources (acting as pull-ups
+ or pull-downs) and the hardware tri-state registers. Because of this
+ physical constraint:
+ - Consumers using pins as outputs MUST flag them with GPIO_OPEN_DRAIN or
+ GPIO_OPEN_SOURCE in the device tree.
+ - Push-pull configurations are physically unsupported.
+ - The active polarity depends entirely on the external circuit (e.g., how
+ an LED is wired) and must be flagged accordingly by the consumer.
+
+allOf:
+ - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+ compatible:
+ enum:
+ - nxp,mc33978
+ - nxp,mc34978
+
+ reg:
+ maxItems: 1
+ description: SPI chip select number
+
+ spi-max-frequency:
+ maximum: 8000000
+ description: Maximum SPI clock frequency (up to 8 MHz)
+
+ interrupts:
+ maxItems: 1
+ description:
+ INT_B pin interrupt. Active-low, indicates pin state changes or
+ fault conditions.
+
+ interrupt-controller: true
+
+ '#interrupt-cells':
+ const: 2
+ description:
+ First cell is the IRQ number (0-21 for pins, 22 for faults).
+ Second cell is the trigger type (IRQ_TYPE_* from dt-bindings/interrupt-controller/irq.h).
+
+ '#mux-control-cells':
+ const: 0
+ description:
+ Present if the device AMUX selector is used as a mux provider.
+ Consumers (e.g. io-channel-mux) must provide settle-time-us for the
+ external ADC sampling path.
+
+ vddq-supply:
+ description: Digital supply voltage
+
+ vbatp-supply:
+ description: Battery/power supply
+
+ gpio-controller: true
+
+ '#gpio-cells':
+ const: 2
+
+ ngpios:
+ const: 22
+
+patternProperties:
+ '^.*-grp$':
+ type: object
+ $ref: /schemas/pinctrl/pincfg-node.yaml#
+ additionalProperties: false
+ description: Pin configuration subnodes.
+ properties:
+ pins:
+ items:
+ enum: [sg0, sg1, sg2, sg3, sg4, sg5, sg6, sg7, sg8, sg9,
+ sg10, sg11, sg12, sg13, sp0, sp1, sp2, sp3,
+ sp4, sp5, sp6, sp7]
+
+ bias-pull-up: true
+ bias-pull-down: true
+ bias-high-impedance: true
+ bias-disable: true
+ drive-open-drain: true
+ drive-open-source: true
+ drive-strength:
+ enum: [2, 6, 8, 10, 12, 14, 16, 20]
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - interrupt-controller
+ - '#interrupt-cells'
+ - vddq-supply
+ - vbatp-supply
+ - gpio-controller
+ - '#gpio-cells'
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+ #include <dt-bindings/gpio/gpio.h>
+
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ msdi: gpio@0 {
+ compatible = "nxp,mc33978";
+ reg = <0>;
+ spi-max-frequency = <4000000>;
+
+ interrupt-parent = <&gpiog>;
+ interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ interrupt-controller;
+ #interrupt-cells = <2>;
+
+ vddq-supply = <®_3v3>;
+ vbatp-supply = <®_12v>;
+
+ #mux-control-cells = <0>;
+
+ gpio-controller;
+ #gpio-cells = <2>;
+ ngpios = <22>;
+
+ door-grp {
+ pins = "sg0";
+ bias-high-impedance;
+ };
+ };
+ };