[PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation

["Nuno Sá" <nuno.sa@analog.com>]

Document the LTC2983 temperature sensor devicetree bindings.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 .../bindings/iio/temperature/adi,ltc2983.yaml | 442 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 443 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml

diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
new file mode 100644
index 000000000000..2b468b3ed177
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
@@ -0,0 +1,442 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LTC2983 Multi-sensor Temperature system
+
+maintainers:
+  - Nuno Sá <nuno.sa@analog.com>
+
+description: |
+  Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
+  https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ltc2983
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  adi,temperature-celcius:
+    description:
+      If this property is present, the temperature is reported in Celsius.
+    type: boolean
+    maxItems: 1
+
+  adi,mux-delay-config:
+    description:
+      The LTC2983 performs 2 or 3 internal conversion cycles per temperature result.
+      Each conversion cycle is performed with different excitation and input multiplexer
+      configurations. Prior to each conversion, these excitation circuits and input
+      switch configurations are changed and an internal 1ms delay ensures settling prior
+      to the conversion cycle in most cases. An extra delay can be configured using this
+      property. The value written here is multiplied by 100us.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - maximum: 255
+        maxItems: 1
+
+  adi,filter-notch-freq:
+    description:
+      Set's the default setting of the digital filter. The default is simultaneous
+      50/60Hz rejection.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [0, 1, 2]
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^thermocouple@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a thermocouple sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential thermocouples, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+           Identifies the type of thermocouple connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1 2 3 4 5 6 7 8]
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 14 of the
+          datasheet for how to set this value for thermocouples.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - minimum: 1
+          - maximun: 15
+        maxItems: 1
+
+      adi,cold-junction-handle:
+        description: |
+          Phandle which points to a sensor object responsible for measuring the
+          thermocouple cold junction temperature.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of voltage(mv)-temperature(K).
+          The entries must be given in nv and uK so that, the original values must be
+          multiplied by 1000000. For more details look at table 69 and 70.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/int64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^diode@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a diode sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description:
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential diodes, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a diode.
+        const: 28
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 17 of the
+          datasheet for how to set this value for diodes.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3 4 5 6 7]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the diode. Look at table 19 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3]
+        maxItems: 1
+
+      adi,ideal-factor-value:
+        description: |
+          This property sets the diode ideality factor. The real value must be
+          multiplied by 1000000 to remove the fractional part. For more information
+          look at table 20 of the datasheet.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+        maxItems: 1
+
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^rtd@([2-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a rtd sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+        minimum: 2
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the type of RTD connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [10 11 12 13 14 15 16 17]
+        maxItems: 1
+
+      adi,rsense-handle:
+        description: |
+          Phandle pointing to a rsense object associated with this RTD.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 28 of the
+          datasheet for how to set this value for RTD's.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 4 5 8 9 10 12 13 14]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the RTD. Look at table 29 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1 2 3 4 5 6 7 8]
+        maxItems: 1
+
+      adi,rtd-curve:
+        description: |
+          This property set the RTD curve used and the corresponding Callendar-Van
+          Dusen constants. Look at table 30 of the datasheet.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3]
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
+          The entries added here are in uohm and uK. For more details values look at table 74 and 75.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+      - adi,rsense-handle
+
+patternProperties:
+  "^thermistor@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a thermistor sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential thermistors, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the type of thermistor connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [19 20 21 22 23 24 25]
+        maxItems: 1
+
+      adi,rsense-handle:
+        description: |
+          Phandle pointing to a rsense object associated with this thermistor.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 52 of the
+          datasheet for how to set this value for thermistors.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 4]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the thermistor. Look at table 53 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-array
+          - enum: [1 2 3 4 5 6 7 8 9 10 11 12]
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
+          The entries added here are in uohm and uK only for custom thermistors.
+          For more details look at table 78 and 79.
+          Steinhart-Hart coefficients are also supported and can be programmed into the
+          device memory using this property. For Steinhart sensors, this table has a constant
+          size of 6 entries (defining the coefficients) and the values are given in the raw format.
+          Look at table 82 for more information.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+      - adi,rsense-handle
+
+patternProperties:
+  "^adc@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a channel which is being used as a direct adc.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential adc's, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a direct adc.
+        const: 30
+        maxItems: 1
+
+      adi,single-ended:
+        description: |
+          Boolean property which set's the adc as single-ended.
+        type: boolean
+
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^rsense@([2-9]|1[0-9]|20)$":
+    type: object
+    description: |
+      Represents a rsense which is connected to one of the device channels.
+      Rsense are used by thermistors and RTD's.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+        minimum: 2
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a rsense.
+        const: 29
+        maxItems: 1
+
+      adi,rsense-val-micro-ohms:
+        description: |
+          Sets the value of the sense resistor. Look at table 20 of the datasheet
+          for information.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64
+        maxItems: 1
+
+    required:
+      - reg
+      - adi,sensor-type
+      - adi, rsense-val
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        sensor_ltc2983: ltc2983@0 {
+                compatible = "adi,ltc2983";
+                reg = <0>;
+
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                adi,temperature-celcius;
+                interrupts = <20 IRQ_TYPE_EDGE_RISING>;
+                interrupt-parent = <&gpio>;
+
+                thermocouple@18 {
+                        reg = <18>;
+                        adi,sensor-type = <8>; //Type B
+                        adi,sensor-config = <1>; //Differential, open-circuit current
+                        adi,cold-junction-handle = <&diode5>;
+                };
+
+                diode5: diode@5 {
+                        reg = <5>;
+                        adi,sensor-type = <28>;
+                };
+
+                rsense2: rsense@2 {
+                        reg = <2>;
+                        adi,sensor-type = <29>;
+                        adi,rsense-val-micro-ohms = /bits/ 64 <1200000000>; //1.2Kohms
+                };
+
+                rtd@14 {
+                        reg = <14>;
+                        adi,sensor-type = <15>; //PT1000
+                        /*2-wire, internal gnd, no current rotation*/
+                        adi,sensor-config = <1>;
+                        adi,excitation-current = <7>; //500uA
+                        adi,rsense-handle = <&rsense2>;
+                };
+
+                adc@10 {
+                        reg = <10>;
+                        adi,sensor-type = <30>;
+                        adi,single-ended;
+                };
+
+                thermistor@12 {
+                        reg = <12>;
+                        adi,sensor-type = <26>; //Steinhart
+                        adi,rsense-handle = <&rsense2>;
+                        adi,custom-sensor = /bits/ 64 <0x00F371EC 0x12345678
+                                        0x2C0F8733 0x10018C66 0xA0FEACCD
+                                        0x90021D99>; //6 entries
+                };
+
+                thermocouple@20 {
+                        reg = <20>;
+                        adi,sensor-type = <9>; //custom thermocouple
+                        adi,sensor-config = <8>; //single-ended
+                        adi,custom-sensor = /bits/ 64
+                                 <(-50220000) 0
+                                  (-30200000) 99100000
+                                  (-5300000) 135400000
+                                  0 273150000
+                                  40200000 361200000
+                                  55300000 522100000
+                                  88300000 720300000
+                                  132200000 811200000
+                                  188700000 922500000
+                                  460400000 1000000000>; //10 pairs
+               };
+
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 14a256e785ca..f747a9dc27f5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9497,6 +9497,7 @@ W:	http://ez.analog.com/community/linux-device-drivers
 L:	linux-iio@vger.kernel.org
 S:	Supported
 F:	drivers/iio/temperature/ltc2983.c
+F:	Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
 
 LTC4261 HARDWARE MONITOR DRIVER
 M:	Guenter Roeck <linux@roeck-us.net>
-- 
2.23.0