[PATCH v2 1/2] dt-bindings: hwmon: temperature: add support for EMC1812

Marius Cristea
2025-11-21T08:49:23Z

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>
---
.../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

--
2.51.0