[PATCH v4 2/2] dt-bindings: iio: Add ltc2983 documentation

Nuno Sá
2019-10-11T08:43:10Z

Document the LTC2983 temperature sensor devicetree bindings.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
Changes in v2:
* Drop maxItems in non-array elements;
* Set adi,mux-delay-config-us instead of adi,mux-delay-config;
* Wrapped lines at 80 char;
* Added comas to enum elements;
* Use real units in adi,excitation-current;
* Moved some enums to minimum and maximum;
* Grouped patternProperties and moved reg property as a generic property.

Changes in v3:
* Add meaning to adi,sensor-type values which are not const;
* Add meaning to adi,filter-notch-freq values;
* Break up adi,sensor-config into human readable elements;
* Set maxItems/minItems at the same identation as allOf in adi,custom-sensor;
* Fixed the maximum value for adi,sensor-type for sensors with custom support;
* Changed license to GPL-2.0-only as it should be for new bindings;
* Changed spi0 to spi in the dts example;
* Updated the dts example to the new properties.

Changes in v4:
* Set correct license for new bindings;
* Drop $ref for standard unit suffixes;
* Dropped adi,temperature-celcius;
* Drop '.*' in the patternProperties regex;
* Make min/man a single schema;
* Have rsense in milli ohms;
* Dropped '|' when no formatting is needed;
* Add matrixes for adi,custom-sensors;
* Rename adi,custom-sensor to a more appropriate and distinct name;
* Add adi,custom-stenheirt for thermistors.

.../bindings/iio/temperature/adi,ltc2983.yaml | 478 ++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 479 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..b4946c6530c0
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
@@ -0,0 +1,478 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%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,mux-delay-config-us:
+ 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 is
+ rounded to nearest 100us.
+ maximum: 255
+
+ adi,filter-notch-freq:
+ description:
+ Set's the default setting of the digital filter. The default is
+ simultaneous 50/60Hz rejection.
+ 0 - 50/60Hz rejection
+ 1 - 60Hz rejection
+ 2 - 50Hz rejection
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - minimum: 0
+ maximum: 2
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+patternProperties:
+ "@([1-9]|1[0-9]|20)$":
+ type: object
+
+ properties:
+ reg:
+ description:
+ The channel number. It can be connected to one of the 20 channels of
+ the device.
+ minimum: 1
+ maximum: 20
+
+ adi,sensor-type:
+ description: Identifies the type of sensor connected to the device.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ required:
+ - reg
+ - adi,sensor-type
+
+ "^thermocouple@":
+ type: object
+ description:
+ Represents a thermocouple sensor which is connected to one of the device
+ channels.
+
+ properties:
+ adi,sensor-type:
+ description: |
+ 1 - Type J Thermocouple
+ 2 - Type K Thermocouple
+ 3 - Type E Thermocouple
+ 4 - Type N Thermocouple
+ 5 - Type R Thermocouple
+ 6 - Type S Thermocouple
+ 7 - Type T Thermocouple
+ 8 - Type B Thermocouple
+ 9 - Custom Thermocouple
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 9
+
+ adi,single-ended:
+ description:
+ Boolean property which set's the thermocouple as single-ended.
+ type: boolean
+
+ adi,sensor-oc-current-microamp:
+ description:
+ This property set's the pulsed current value applied during
+ open-circuit detect.
+ enum: [10, 100, 500, 1000]
+
+ 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"
+
+ adi,custom-thermocouple:
+ 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-matrix
+ items:
+ minItems: 3
+ maxItems: 64
+ items:
+ minItems: 2
+ maxItems: 2
+
+ "^diode@":
+ type: object
+ description:
+ Represents a diode sensor which is connected to one of the device
+ channels.
+
+ properties:
+ adi,sensor-type:
+ description: Identifies the sensor as a diode.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ const: 28
+
+ adi,single-ended:
+ description: Boolean property which set's the diode as single-ended.
+ type: boolean
+
+ adi,three-conversion-cycles:
+ description:
+ Boolean property which set's three conversion cycles removing
+ parasitic resistance effects between the LTC2983 and the diode.
+ type: boolean
+
+ adi,average-on:
+ description:
+ Boolean property which enables a running average of the diode
+ temperature reading. This reduces the noise when the diode is used
+ as a cold junction temperature element on an isothermal block
+ where temperatures change slowly.
+ type: boolean
+
+ adi,excitation-current-microamp:
+ description:
+ This property controls the magnitude of the excitation current
+ applied to the diode. Depending on the number of conversions
+ cycles, this property will assume different predefined values on
+ each cycle. Just set the value of the first cycle (1l).
+ enum: [10, 20, 40, 80]
+
+ 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.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ "^rtd@":
+ type: object
+ description:
+ Represents a rtd sensor which is connected to one of the device channels.
+
+ properties:
+ reg:
+ minimum: 2
+ maximum: 20
+
+ adi,sensor-type:
+ description: |
+ 10 - RTD PT-10
+ 11 - RTD PT-50
+ 12 - RTD PT-100
+ 13 - RTD PT-200
+ 14 - RTD PT-500
+ 15 - RTD PT-1000
+ 16 - RTD PT-1000 (0.00375)
+ 17 - RTD NI-120
+ 18 - RTD Custom
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 10
+ maximum: 18
+
+ adi,rsense-handle:
+ description:
+ Phandle pointing to a rsense object associated with this RTD.
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+
+ adi,number-of-wires:
+ description:
+ Identifies the number of wires used by the RTD. Setting this
+ property to 5 means 4 wires with Kelvin Rsense.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - enum: [2, 3, 4, 5]
+
+ adi,rsense-share:
+ description:
+ Boolean property which enables Rsense sharing, where one sense
+ resistor is used for multiple 2-, 3-, and/or 4-wire RTDs.
+ type: boolean
+
+ adi,current-rotate:
+ description:
+ Boolean property which enables excitation current rotation to
+ automatically remove parasitic thermocouple effects. Note that
+ this property is not allowed for 2- and 3-wire RTDs.
+ type: boolean
+
+ adi,excitation-current-microamp:
+ description:
+ This property controls the magnitude of the excitation current
+ applied to the RTD.
+ enum: [5, 10, 25, 50, 100, 250, 500, 1000]
+
+ adi,rtd-curve:
+ description:
+ This property set the RTD curve used and the corresponding
+ Callendar-VanDusen constants. Look at table 30 of the datasheet.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - minimum: 0
+ maximum: 3
+
+ adi,custom-rtd:
+ 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-matrix
+ items:
+ minItems: 3
+ maxItems: 64
+ items:
+ minItems: 2
+ maxItems: 2
+
+ required:
+ - adi,rsense-handle
+
+ dependencies:
+ adi,current-rotate: [ adi,rsense-share ]
+
+ "^thermistor@":
+ type: object
+ description:
+ Represents a thermistor sensor which is connected to one of the device
+ channels.
+
+ properties:
+ adi,sensor-type:
+ description:
+ 19 - Thermistor 44004/44033 2.252kohm at 25°C
+ 20 - Thermistor 44005/44030 3kohm at 25°C
+ 21 - Thermistor 44007/44034 5kohm at 25°C
+ 22 - Thermistor 44006/44031 10kohm at 25°C
+ 23 - Thermistor 44008/44032 30kohm at 25°C
+ 24 - Thermistor YSI 400 2.252kohm at 25°C
+ 25 - Thermistor Spectrum 1003k 1kohm
+ 26 - Thermistor Custom Steinhart-Hart
+ 27 - Custom Thermistor
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 19
+ maximum: 27
+
+ adi,rsense-handle:
+ description:
+ Phandle pointing to a rsense object associated with this
+ thermistor.
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+
+ adi,single-ended:
+ description:
+ Boolean property which set's the thermistor as single-ended.
+ type: boolean
+
+ adi,rsense-share:
+ description:
+ Boolean property which enables Rsense sharing, where one sense
+ resistor is used for multiple thermistors. Note that this property
+ is ignored if adi,single-ended is set.
+ type: boolean
+
+ adi,current-rotate:
+ description:
+ Boolean property which enables excitation current rotation to
+ automatically remove parasitic thermocouple effects.
+ type: boolean
+
+ adi,excitation-current-nanoamp:
+ description:
+ This property controls the magnitude of the excitation current
+ applied to the thermistor. Value 0 set's the sensor in auto-range
+ mode.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - enum: [0, 250, 500, 1000, 5000, 10000, 25000, 50000, 100000,
+ 250000, 500000, 1000000]
+
+ adi,custom-thermistor:
+ 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.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint64-matrix
+ items:
+ minItems: 3
+ maxItems: 64
+ items:
+ minItems: 2
+ maxItems: 2
+
+ adi,custom-steinhart:
+ description:
+ Steinhart-Hart coefficients are also supported and can
+ be programmed into the device memory using this property. For
+ Steinhart sensors the coefficients are given in the raw
+ format. Look at table 82 for more information.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32-array
+ items:
+ minItems: 6
+ maxItems: 6
+
+ required:
+ - adi,rsense-handle
+
+ dependencies:
+ adi,current-rotate: [ adi,rsense-share ]
+
+ "^adc@":
+ type: object
+ description: Represents a channel which is being used as a direct adc.
+
+ properties:
+ adi,sensor-type:
+ description: Identifies the sensor as a direct adc.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ const: 30
+
+ adi,single-ended:
+ description: Boolean property which set's the adc as single-ended.
+ type: boolean
+
+ "^rsense@":
+ 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:
+ minimum: 2
+ maximum: 20
+
+ adi,sensor-type:
+ description: Identifies the sensor as a rsense.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ const: 29
+
+ adi,rsense-val-milli-ohms:
+ description:
+ Sets the value of the sense resistor. Look at table 20 of the
+ datasheet for information.
+
+ required:
+ - adi,rsense-val-milli-ohms
+
+required:
+ - compatible
+ - reg
+ - interrupts
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ sensor_ltc2983: ltc2983@0 {
+ compatible = "adi,ltc2983";
+ reg = <0>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ interrupts = <20 IRQ_TYPE_EDGE_RISING>;
+ interrupt-parent = <&gpio>;
+
+ thermocouple@18 {
+ reg = <18>;
+ adi,sensor-type = <8>; //Type B
+ adi,sensor-oc-current-microamp = <10>;
+ 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-milli-ohms = <1200000>; //1.2Kohms
+ };
+
+ rtd@14 {
+ reg = <14>;
+ adi,sensor-type = <15>; //PT1000
+ /*2-wire, internal gnd, no current rotation*/
+ adi,number-of-wires = <2>;
+ adi,rsense-share;
+ adi,excitation-current-microamp = <500>;
+ 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-steinhart = <0x00F371EC 0x12345678
+ 0x2C0F8733 0x10018C66 0xA0FEACCD
+ 0x90021D99>; //6 entries
+ };
+
+ thermocouple@20 {
+ reg = <20>;
+ adi,sensor-type = <9>; //custom thermocouple
+ adi,single-ended;
+ adi,custom-thermocouple = /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