Re: [PATCH v5 1/7] dt-bindings: pinctrl: add NXP MC33978/MC34978 MSDI

[Rob Herring (Arm)]

On Mon, 16 Mar 2026 15:05:06 +0100, Oleksij Rempel wrote:
> Add device tree binding documentation for the NXP MC33978 and MC34978
> Multiple Switch Detection Interface (MSDI) devices.
> 
> The MC33978 and MC34978 differ primarily in their operating temperature
> ranges. While not software-detectable, providing specific compatible
> strings allows the hwmon subsystem to correctly interpret thermal
> thresholds and hardware faults.
> 
> These ICs monitor up to 22 mechanical switch contacts in automotive and
> industrial environments. They provide configurable wetting currents to
> break through contact oxidation and feature extensive hardware
> protection against thermal overload and voltage transients (load
> dumps/brown-outs).
> 
> The device interfaces via SPI. While it provides multiple functions, its
> primary hardware purpose is pin/switch control. To accurately represent
> the hardware as a single physical integrated circuit without unnecessary
> DT overhead, all functions are flattened into a single pinctrl node:
> - pinctrl: Exposing the 22 switch inputs (SG/SP pins) as a GPIO controller
>   and managing their pin configurations.
> - hwmon: Exposing critical hardware faults (OT, OV, UV) and static
>   voltage/temperature thresholds.
> - mux: Controlling the 24-to-1 analog multiplexer to route pin voltages,
>   internal temperature, or battery voltage to an external SoC ADC.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> ---
> changes v5:
> - Commit Message: Added justification for distinct compatible strings
>   based on temperature ranges.
> - Restricted pins property to an explicit enum of valid hardware pins
> changes v4:
> - Drop the standalone mfd/nxp,mc33978.yaml schema entirely.
> - Move the unified device binding to bindings/pinctrl/nxp,mc33978.yaml,
> - Remove the dedicated child node compatible strings (nxp,mc33978-pinctrl).
> - Flatten the pinctrl/gpio properties directly into the main SPI device
>   node.
> changes v3:
> - Drop regular expression pattern from pinctrl child node and define
>   it as a standard property
> - Reorder required properties list in MFD binding
> - Remove stray blank line from the MFD binding devicetree example
> - Replace unevaluatedProperties with additionalProperties in the pinctrl
>   binding
> changes v2:
> - Squashed MFD, pinctrl, hwmon, and mux bindings into a single patch
> - Removed the empty hwmon child node
> - Folded the mux-controller node into the parent MFD node
> - Added vbatp-supply and vddq-supply to the required properties block
> - Changed the example node name from mc33978@0 to gpio@0
> - Removed unnecessary literal block scalars (|) from descriptions
> - Documented SG, SP, and SB pin acronyms in the pinctrl description
> - Added consumer polarity guidance (GPIO_ACTIVE_LOW/HIGH) for SG/SB
>   inputs, with a note on output circuit dependency
> - Updated commit message
> ---
>  .../bindings/pinctrl/nxp,mc33978.yaml         | 153 ++++++++++++++++++
>  1 file changed, 153 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/nxp,mc33978.yaml
> 

Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>