[PATCH 1/2] dt-bindings: iio: temperature: add support for EMC1812
From: Marius Cristea <marius.cristea@microchip.com>
Date: 2025-09-17 12:23:10
Also in:
linux-iio, lkml
Subsystem:
iio subsystem and drivers, open firmware and flattened device tree bindings, the rest · Maintainers:
Jonathan Cameron, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
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> --- .../iio/temperature/microchip,emc1812.yaml | 223 +++++++++++++++++++++ MAINTAINERS | 6 + 2 files changed, 229 insertions(+)
diff --git a/Documentation/devicetree/bindings/iio/temperature/microchip,emc1812.yaml b/Documentation/devicetree/bindings/iio/temperature/microchip,emc1812.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..898d6d246746e229cb004f447872ee6bd5a65074
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/microchip,emc1812.yaml@@ -0,0 +1,223 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/temperature/microchip,emc1812.yaml# +$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 + + 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. + items: + - const: alert-therm2 + - const: therm-addr + + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + + microchip,beta1: + description: + Set beta compensation value for external channel 1. + <0> 0.050 + <1> 0.066 + <2> 0.087 + <3> 0.114 + <4> 0.150 + <5> 0.197 + <6> 0.260 + <7> 0.342 + <8> 0.449 + <9> 0.591 + <10> 0.778 + <11> 1.024 + <12> 1.348 + <13> 1.773 + <14> 2.333 + <15> Diode_Mode + <16> Auto + - Diode_Mode is used when measuring a discrete thermal diode + or a CPU diode that functions like a discrete thermal diode. + - Auto enables beta auto-detection. The chip monitors + external diode/transistor and determines the optimum + setting. + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 0 + maximum: 16 + default: 16 + + microchip,beta2: + description: + Set beta compensation value for external channel 2. + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 0 + maximum: 16 + default: 16 + + microchip,parasitic-res-on-channel1-2: + description: + Indicates that the chip and the diodes/transistors are sufficiently far + apart that a parasitic resistance is added to the wires, which can affect + the measurements. Due to the anti-parallel diode connections, channels + 1 and 2 are affected together. + type: boolean + + microchip,parasitic-res-on-channel3-4: + description: + Indicates that the chip and the diodes/transistors are sufficiently far + apart that a parasitic resistance is added to the wires, which can affect + the measurements. Due to the anti-parallel diode connections, channels + 3 and 4 are affected together. + type: boolean + + vdd-supply: true + +patternProperties: + "^channel@[1-4]$": + description: + Represents the external temperature channels to which + a remote diode is connected. + type: object + + properties: + reg: + items: + minimum: 1 + maximum: 4 + + microchip,ideality-factor: + description: + Each channel has an ideality factor. + Beta compensation and resistance error correction automatically + correct for most ideality errors. So ideality factor does not need + to be adjusted in general. + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 8 + maximum: 55 + default: 18 + + label: + description: Unique name to identify which channel this is. + + required: + - reg + + additionalProperties: false + +required: + - compatible + - reg + - vdd-supply + +allOf: + - if: + properties: + compatible: + contains: + enum: + - microchip,emc1812 + - microchip,emc1813 + - microchip,emc1833 + then: + properties: + microchip,beta2: false + microchip,parasitic-res-on-channel3-4: false + - if: + properties: + compatible: + pattern: "^microchip,emc1812" + then: + patternProperties: + "^channel@1$": + properties: + reg: + items: + maximum: 1 + "^channel@[2-4]$": false + - if: + properties: + compatible: + pattern: "^microchip,emc18[13]3" + then: + patternProperties: + "^channel@[12]$": + properties: + reg: + items: + maximum: 1 + "^channel@[34]$": false + - if: + properties: + compatible: + pattern: "^microchip,emc1814" + then: + patternProperties: + "^channel@[1-3]$": + properties: + reg: + items: + maximum: 1 + "^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; + + microchip,beta1 = <16>; + 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 a92290fffa163f9fe8fe3f04bf66426f9a894409..09efda36a17e398b3ad807ac47485e530154bae4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS@@ -22862,6 +22862,12 @@ M: Nicolas Pitre <nico@fluxnic.net> S: Odd Fixes F: drivers/net/ethernet/smsc/smc91x.* +MICROCHIP EMC1812 TEMPERATURE DRIVER +M: Marius Cristea <marius.cristea@microchip.com> +L: linux-iio@vger.kernel.org +S: Supported +F: Documentation/devicetree/bindings/iio/temperature/microchip,emc1812.yaml + SMSC EMC2103 HARDWARE MONITOR DRIVER M: Steve Glendinning <steve.glendinning@shawell.net> L: linux-hwmon@vger.kernel.org
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