This is the devicetree schema for Microchip EMC1812/13/14/15/33
Multichannel Low-Voltage Remote Diode Sensor Family.
EMC1812 has one external remote temperature monitoring channel.
EMC1813 has two external remote temperature monitoring channels.
EMC1814 has three external remote temperature monitoring channels and
channels 2 and 3 supports anti parallel diode.
EMC1815 has four external remote temperature monitoring channels and
channels 1/2 and 3/4 supports anti parallel diode.
EMC1833 has two external remote temperature monitoring channels and
channels 1 and 2 supports anti parallel diode.
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
.../bindings/hwmon/microchip,emc1812.yaml | 182 +++++++++++++++++++++
MAINTAINERS | 6 +
2 files changed, 188 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..759e004eafdfc0772e110fe484767eb66a623294
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
@@ -0,0 +1,182 @@
+# 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
+
+ EMC1812 has one external remote temperature monitoring channel
+ EMC1813 has two external remote temperature monitoring channels
+ EMC1814 has three external remote temperature monitoring channels and
+ channels 2 and 3 supports anti parallel diode
+ EMC1815 has four external remote temperature monitoring channels and
+ channels 1/2 and 3/4 supports anti parallel diode
+ EMC1833 has two external remote temperature monitoring channels and
+ channels 1 and 2 supports anti parallel diode
+
+properties:
+ compatible:
+ enum:
+ - microchip,emc1812
+ - microchip,emc1813
+ - microchip,emc1814
+ - microchip,emc1815
+ - microchip,emc1833
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ items:
+ - description: alert-therm2 asserts when the ALERT limit is exceeded.
+ - description: therm-addr asserts when the THERM limit is exceeded.
+ minItems: 1
+
+ interrupt-names:
+ items:
+ - enum: [alert-therm2, therm-addr]
+
+ "#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
--
2.51.0On Thu, Feb 05, 2026 at 09:09:03AM +0200, Marius Cristea wrote:
> This is the devicetree schema for Microchip EMC1812/13/14/15/33
> Multichannel Low-Voltage Remote Diode Sensor Family.
>
> EMC1812 has one external remote temperature monitoring channel.
> EMC1813 has two external remote temperature monitoring channels.
> EMC1814 has three external remote temperature monitoring channels and
> channels 2 and 3 supports anti parallel diode.
> EMC1815 has four external remote temperature monitoring channels and
> channels 1/2 and 3/4 supports anti parallel diode.
> EMC1833 has two external remote temperature monitoring channels and
> channels 1 and 2 supports anti parallel diode.
>
> Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> ---
> .../bindings/hwmon/microchip,emc1812.yaml | 182 +++++++++++++++++++++
> MAINTAINERS | 6 +
> 2 files changed, 188 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..759e004eafdfc0772e110fe484767eb66a623294
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> @@ -0,0 +1,182 @@
> +# 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
> +
> + EMC1812 has one external remote temperature monitoring channel
> + EMC1813 has two external remote temperature monitoring channels
> + EMC1814 has three external remote temperature monitoring channels and
> + channels 2 and 3 supports anti parallel diode
> + EMC1815 has four external remote temperature monitoring channels and
> + channels 1/2 and 3/4 supports anti parallel diode
> + EMC1833 has two external remote temperature monitoring channels and
> + channels 1 and 2 supports anti parallel diode
> +
> +properties:
> + compatible:
> + enum:
> + - microchip,emc1812
> + - microchip,emc1813
> + - microchip,emc1814
> + - microchip,emc1815
> + - microchip,emc1833
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + items:
> + - description: alert-therm2 asserts when the ALERT limit is exceeded.
> + - description: therm-addr asserts when the THERM limit is exceeded.
> + minItems: 1
> +
> + interrupt-names:
> + items:
> + - enum: [alert-therm2, therm-addr]
AI feedback:
If interrupt names are being used to identify the interrupts, should
the interrupts property be less restrictive?
Currently, the items list in interrupts enforces a strict order:
the first interrupt must match the first description (alert-therm2),
and the second must match the second description (therm-addr).
However, the interrupt-names definition for the first item allows it
to be "therm-addr".
If the intention is to support providing only the second interrupt (therm-addr)
as the first item in the list, then the interrupts property definition
prevents that by enforcing the first item to be alert-therm2.
2nd feedback:
The interrupts property description lists two possible interrupts ("alert-therm2"
and "therm-addr"), but this definition restricts interrupt-names to a single
item.
Should this be updated to allow providing names for both interrupts if the
device is configured with both?
[ I don't know how this is supposed to work, so the feedback needs to be taken
with two grains of salt. ]
> +
> + "#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
I (or, rather, AI review) asked this before:
Does this reg property need maxItems: 1?
Without it, the schema might allow reg properties with multiple items,
provided the first item is within the minimum/maximum range.
[ Presumably the _values_ should be 1..4, not the number of items ]
> +
> + 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
>
> --
> 2.51.0
>
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