[PATCH v10 1/2] dt-bindings: hwmon: 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. It also
updates the MAINTAINERS file to include the new driver.

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 support anti parallel diode.
EMC1815 has four external remote temperature monitoring channels and
channels 1/2  and 3/4 support anti parallel diode.
EMC1833 has two external remote temperature monitoring channels and
channels 1 and 2 support anti parallel diode.
Resistance Error Correction is supported on channels 1/2 and 3/4.

Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
 .../bindings/hwmon/microchip,emc1812.yaml          | 193 +++++++++++++++++++++
 MAINTAINERS                                        |   6 +
 2 files changed, 199 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..1a273621db826db66f0c33b1b2f5c72c0788a6ae
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
@@ -0,0 +1,193 @@
+# 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 support anti parallel diode
+  EMC1815 has four external remote temperature monitoring channels and
+    channels 1/2 and 3/4 support anti parallel diode
+  EMC1833 has two external remote temperature monitoring channels and
+    channels 1 and 2 support 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:
+      - const: alert-therm2
+      - const: therm-addr
+    minItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  microchip,enable-anti-parallel:
+    description:
+      Enable anti-parallel diode mode operation. EMC1814, EMC1815 and EMC1833
+      support reading two external diodes in anti-parallel connection on the
+      same set of pins. Disabling APD functionality to implement substrate
+      diodes on devices that support APD eliminates the benefit of APD
+      (two diodes on one channel).
+    type: boolean
+
+  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 availability of only a single
+      configuration bit in hardware, channels 1 and 2 are affected together.
+      If channel 2 is not available in hardware, this setting affects only
+      channel 1.
+    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 availability of only a single
+      configuration bit in hardware, channels 3 and 4 are affected together.
+      If channel 4 is not available in hardware, this setting affects only
+      channel 3.
+    type: boolean
+
+  vdd-supply: true
+
+patternProperties:
+  "^channel@[0-4]$":
+    description: |
+      Represents the temperature channels.
+      0: Internal sensor
+      1-4: External remote diodes
+    type: object
+
+    properties:
+      reg:
+        maxItems: 1
+
+      label:
+        description: Unique name to identify which channel this is.
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+allOf:
+  # EMC1812: 1 Internal, 1 External Channels, No APD,
+  # parasitic-res-on-channel1-2: for channel 1
+  - if:
+      properties:
+        compatible:
+          const: microchip,emc1812
+    then:
+      properties:
+        microchip,enable-anti-parallel: false
+        microchip,parasitic-res-on-channel3-4: false
+      patternProperties:
+        "^channel@[2-4]$": false
+
+  # EMC1813: 1 Internal, 2 External Channels, No APD,
+  # parasitic-res-on-channel1-2: on both channel 1 & 2
+  - if:
+      properties:
+        compatible:
+          const: microchip,emc1813
+    then:
+      properties:
+        microchip,enable-anti-parallel: false
+        microchip,parasitic-res-on-channel3-4: false
+      patternProperties:
+        "^channel@[3-4]$": false
+
+  # EMC1833: 1 Internal, 2 External Channels, Supports APD,
+  # parasitic-res-on-channel1-2: on both channel 1 & 2
+  - if:
+      properties:
+        compatible:
+          const: microchip,emc1833
+    then:
+      properties:
+        microchip,parasitic-res-on-channel3-4: false
+      patternProperties:
+        "^channel@[3-4]$": false
+
+  # EMC1814: 1 Internal, 3 External Channels, Supports APD,
+  # parasitic-res-on-channel1-2: on both channel 1 & 2
+  # parasitic-res-on-channel3-4: for channel 3
+  - if:
+      properties:
+        compatible:
+          const: microchip,emc1814
+    then:
+      properties:
+        channel@4: false
+
+unevaluatedProperties: 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