From: Jonathan Cameron <jic23@kernel.org>
To: "Nuno Sá" <nuno.sa@analog.com>
Cc: <linux-iio@vger.kernel.org>, <devicetree@vger.kernel.org>,
<knaack.h@gmx.de>, <lars@metafoo.de>, <pmeerw@pmeerw.net>,
<robh+dt@kernel.org>, <mark.rutland@arm.com>
Subject: Re: [RESEND PATCH v2 2/2] dt-bindings: iio: Add ltc2983 documentation
Date: Tue, 1 Oct 2019 10:16:13 +0100 [thread overview]
Message-ID: <20191001101613.50d825a9@archlinux> (raw)
In-Reply-To: <20190930104247.21519-2-nuno.sa@analog.com>
On Mon, 30 Sep 2019 12:42:47 +0200
Nuno Sá <nuno.sa@analog.com> wrote:
> Document the LTC2983 temperature sensor devicetree bindings.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Hi Nuno,
A few comments inline. This is a complex one so I'll definitely be
looking for a review from Rob or Mark,
Thanks,
Jonathan
> ---
> 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.
>
> .../bindings/iio/temperature/adi,ltc2983.yaml | 406 ++++++++++++++++++
> MAINTAINERS | 1 +
> 2 files changed, 407 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..df68b8233e5e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> @@ -0,0 +1,406 @@
> +# 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
> +
> + 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.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - maximum: 255
> +
> + adi,filter-notch-freq:
> + description:
> + Set's the default setting of the digital filter. The default is
> + simultaneous 50/60Hz rejection.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - minimum: 0
> + - maximum: 2
This one is an oddity and you should define what the 3 values mean.
If the sensor had supported no notch rejection at all rather than just
50, 60, 50/60 I would have suggested two bools but as it stands I guess
this will just need to be an enum.
> +
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> +patternProperties:
> + ".*@([1-9]|1[0-9]|20)$":
> + 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
> +
> + required:
> + - reg
> +
> + patternProperties:
> + "^thermocouple@.*":
> + type: object
> + description: |
> + Represents a thermocouple sensor which is connected to one of the device
> + channels.
> +
> + properties:
> + adi,sensor-type:
> + description: |
> + Identifies the type of thermocouple connected to the device.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - minimum: 1
> + - maximum: 8
Meaning of values should be defined...
> +
> + 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
Hmm. Whilst there are quite a few things in here, it would be nice to break it up
into human readable elements. It's only 3 things and there are a bunch of don't
care states it seems.
> +
> + 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-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:
> + - adi,sensor-type
> +
> + "^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.
> + const: 28
> +
> + 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
> + - minimum: 0
> + - maximum: 7
Another one I'd like to see broken up.
> +
> + 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).
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - 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.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> +
> + required:
> + - adi,sensor-type
> +
> + "^rtd@.*":
> + type: object
> + description: |
> + Represents a rtd sensor which is connected to one of the device channels.
> +
> + properties:
> + reg:
> + minimum: 2
> +
> + adi,sensor-type:
> + description: Identifies the type of RTD connected to the device.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - minimum: 10
> + - maximum: 17
> +
> + adi,rsense-handle:
> + description: |
> + Phandle pointing to a rsense object associated with this RTD.
> + $ref: "/schemas/types.yaml#/definitions/phandle"
> +
> + 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]
Another one to break up into it's parts, which would also get rid of the
enum with gaps element.
> +
> + adi,excitation-current-microamp:
> + description: |
> + This property controls the magnitude of the excitation current
> + applied to the RTD.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - 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-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:
> + - adi,sensor-type
> + - adi,rsense-handle
> +
> + "^thermistor@.*":
> + type: object
> + description: |
> + Represents a thermistor sensor which is connected to one of the device
> + channels.
> +
> + properties:
> + adi,sensor-type:
> + description: |
> + Identifies the type of thermistor connected to the
> + device.
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - minimum: 19
> + - maximum: 25
> +
> + adi,rsense-handle:
> + description: |
> + Phandle pointing to a rsense object associated with this
> + thermistor.
> + $ref: "/schemas/types.yaml#/definitions/phandle"
> +
> + 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
> + - minimum: 0
> + - maximum: 4
Nasty as value 3 is reserved. So break this one up into it's parts as well.
> +
> + 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-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:
> + - adi,sensor-type
> + - adi,rsense-handle
> +
> + "^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.
> + const: 30
> +
> + adi,single-ended:
> + description: Boolean property which set's the adc as single-ended.
> + type: boolean
> +
> + required:
> + - adi,sensor-type
> +
> + "^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
> +
> + adi,sensor-type:
> + description: Identifies the sensor as a rsense.
> + const: 29
> +
> + 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
> +
> + required:
> + - 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>
next prev parent reply other threads:[~2019-10-01 9:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-30 10:42 [RESEND PATCH v2 1/2] iio: temperature: Add support for LTC2983 Nuno Sá
2019-09-30 10:42 ` [RESEND PATCH v2 2/2] dt-bindings: iio: Add ltc2983 documentation Nuno Sá
2019-10-01 9:16 ` Jonathan Cameron [this message]
2019-10-02 12:53 ` Sa, Nuno
2019-10-01 9:03 ` [RESEND PATCH v2 1/2] iio: temperature: Add support for LTC2983 Jonathan Cameron
2019-10-02 12:07 ` Sa, Nuno
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