Re: [PATCH 1/2] dt-bindings: hwmon: temperature: add support for EMC1812

[Conor Dooley <conor@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 7045 bytes --]

On Wed, Oct 29, 2025 at 05:50:58PM +0200, Marius Cristea wrote:
> This is the devicetree schema for Microchip EMC1812/13/14/15/33
> Multichannel Low-Voltage Remote Diode Sensor Family.
> 
> Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> ---
>  .../bindings/hwmon/microchip,emc1812.yaml          | 176 +++++++++++++++++++++
>  MAINTAINERS                                        |   6 +
>  2 files changed, 182 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..cc4c7bb53cb13416c1e9419cc8c6c8a56da22df8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> @@ -0,0 +1,176 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/microchip,emc1812.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip EMC1812/13/14/15/33 multichannel temperature sensor
> +
> +maintainers:
> +  - Marius Cristea <marius.cristea@microchip.com>
> +
> +description: |
> +  The Microchip EMC1812/13/14/15/33 is a high-accuracy 2-wire multichannel
> +  low-voltage remote diode temperature monitor.
> +
> +  The datasheet can be found here:
> +    https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - microchip,emc1812
> +      - microchip,emc1813
> +      - microchip,emc1814
> +      - microchip,emc1815
> +      - microchip,emc1833

Could you add a note to the commit message about what makes these
devices incompatible with one another?

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 2
> +
> +  interrupt-names:
> +    description:
> +      -alert-therm2 asserts when a diode temperature exceeds the ALERT
> +      threshold.
> +      -therm-addr asserts low when the hardware-set THERM limit threshold is
> +      exceeded by one of the temperature sensors.

You should be able to just move this into interrupts:
  interrupts:
    items:
      - description:
          alert-therm2 asserts when a diode temperature exceeds the ALERT
          threshold.
      - description:
          therm-addr asserts low when the hardware-set THERM limit threshold is
          exceeded by one of the temperature sensors.

> +    items:
> +      - const: alert-therm2
> +      - const: therm-addr

Also, should this and interrupts have minItems: 1? Are both actually
required? Can you have therm-addr without alert-therm2?

pw-bot: changes-requested

Cheers,
Conor.

> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  microchip,parasitic-res-on-channel1-2:
> +    description:
> +      Indicates that the chip and the diodes/transistors are sufficiently
> +      far apart that a parasitic resistance is added to the wires, which can
> +      affect the measurements. Due to the anti-parallel diode connections,
> +      channels 1 and 2 are affected together.
> +    type: boolean
> +
> +  microchip,parasitic-res-on-channel3-4:
> +    description:
> +      Indicates that the chip and the diodes/transistors are sufficiently far
> +      apart that a parasitic resistance is added to the wires, which can affect
> +      the measurements. Due to the anti-parallel diode connections, channels
> +      3 and 4 are affected together.
> +    type: boolean
> +
> +  vdd-supply: true
> +
> +patternProperties:
> +  "^channel@[1-4]$":
> +    description:
> +      Represents the external temperature channels to which
> +      a remote diode is connected.
> +    type: object
> +
> +    properties:
> +      reg:
> +        items:
> +          minimum: 1
> +          maximum: 4
> +
> +      label:
> +        description: Unique name to identify which channel this is.
> +
> +    required:
> +      - reg
> +
> +    additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - vdd-supply
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - microchip,emc1812
> +              - microchip,emc1813
> +              - microchip,emc1833
> +    then:
> +      properties:
> +        microchip,parasitic-res-on-channel3-4: false
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - microchip,emc1812
> +    then:
> +      properties:
> +        channel@1:
> +          properties:
> +            reg:
> +              items:
> +                const: 1
> +      patternProperties:
> +        "^channel@[2-4]$": false
> +  - if:
> +      properties:
> +        compatible:
> +          pattern: "^microchip,emc18[13]3"
> +    then:
> +      patternProperties:
> +        "^channel@[12]$":
> +          properties:
> +            reg:
> +              items:
> +                maximum: 2
> +        "^channel@[34]$": false
> +  - if:
> +      properties:
> +        compatible:
> +          pattern: "^microchip,emc1814"
> +    then:
> +      patternProperties:
> +        "^channel@[1-3]$":
> +          properties:
> +            reg:
> +              items:
> +                maximum: 3
> +      properties:
> +        channel@4: false
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        temperature-sensor@4c {
> +            compatible = "microchip,emc1813";
> +            reg = <0x4c>;
> +
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            microchip,parasitic-res-on-channel1-2;
> +
> +            vdd-supply = <&vdd>;
> +
> +            channel@1 {
> +                reg = <1>;
> +                label = "External CH1 Temperature";
> +            };
> +
> +            channel@2 {
> +                reg = <2>;
> +                label = "External CH2 Temperature";
> +            };
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6d7b697bfdba16e4f0ee5f4f0195b9d7da06dae5..85c236df781e47c78deeb7ef4d80bc94bba604c4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16646,6 +16646,12 @@ S:	Supported
>  F:	Documentation/devicetree/bindings/interrupt-controller/microchip,sama7g5-eic.yaml
>  F:	drivers/irqchip/irq-mchp-eic.c
>  
> +MICROCHIP EMC1812 DRIVER
> +M:	Marius Cristea <marius.cristea@microchip.com>
> +L:	linux-hwmon@vger.kernel.org
> +S:	Supported
> +F:	Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> +
>  MICROCHIP I2C DRIVER
>  M:	Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
>  L:	linux-i2c@vger.kernel.org
> 
> -- 
> 2.48.1
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]