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

[Marius Cristea <marius.cristea@microchip.com>]

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

-- 
2.48.1