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

Sa, Nuno
2019-09-16T15:21:06Z

Hi Rob and Jonathan,

Some comments/questions inline.

Nuno Sá

On Sun, 2019-09-15 at 12:07 +0100, Jonathan Cameron wrote:
>
> On Fri, 13 Sep 2019 15:36:21 +0100
> Rob Herring <robh@kernel.org> wrote:
>
> > On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> > > 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.yam
> > > l
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > new file mode 100644
> > > index 000000000000..2b468b3ed177
> > > --- /dev/null
> > > +++
> > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > @@ -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
> >
> > It's a boolean, not an array so 'maxItems' doesn't make sense.
> >
> > Running 'make dt_binding_check' should tell you this. You may need
> > to
> > update dt-schema install though.

Rob, I'm having some issues with `make dt_binding_check`. I updated dt-
schema and I get this when run it:

...
"ruamel.yaml.constructor.DuplicateKeyError: while constructing a
mapping
in "<unicode string>", line 4, column 1
found duplicate key "patternProperties" with value "{}" (original
value: "{}")
in "<unicode string>", line 113, column 1"

If you want, I can paste the complete traceback in a following email.
However I could use `dt-doc-validate
Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml`
directly by doing a manual change in `dt-doc-validate `. I changed the
call `testtree = dtschema.load(filename, line_number=line_number,
duplicate_keys=False)` to `testtree = dtschema.load(filename,
line_number=line_number, duplicate_keys=True)`. Is this something
already known? I would not be surprised if it is some problem in my
environment. However, I even tried this in a clean docker container
based on ubuntu 18.04 and got the same behavior.

> > > +
> > > + 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.
>
> Make this adi,mux-delay-config-us and state it is rounded to nearest
> 100us.
>
> > > + allOf:
> > > + - $ref: /schemas/types.yaml#/definitions/uint32
> > > + - maximum: 255
> > > + maxItems: 1
> >
> > Drop this.
> >
> > > +
> > > + adi,filter-notch-freq:
> > > + description:
> > > + Set's the default setting of the digital filter. The
> > > default is simultaneous
> > > + 50/60Hz rejection.
> > > + allOf:
> > > + - $ref: /schemas/types.yaml#/definitions/uint32
> > > + - enum: [0, 1, 2]
> > > + maxItems: 1
> >
> > Drop this.
> >
> > > +
> > > + '#address-cells':
> > > + const: 1
> > > +
> > > + '#size-cells':
> > > + const: 0
> > > +
> > > +patternProperties:
> > > + "^thermocouple@([1-9]|1[0-9]|20)$":
> > > + type: object
> > > + description: Represents a thermocouple sensor which is
> > > connected to one of the device channels.
> >
> > Wrap lines at 80 char.
> >
> > > +
> > > + 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
> >
> > Drop this and pretty much everywhere else that is never an array.
> >
> > > +
> > > + 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]
> >
> > Missing commas which may not even parse. Maybe be consistent with
> > elsewhere and use minimum and maximum.
> >
> > > + 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
> >
> > As this is pretty much the same for all child nodes, make a pattern
> > that
> > matches all child nodes and put this there rather than duplicating
> > it.
> > Then you only need 'minimum: 2' in the cases needing that.

I'm not sure I'm following your point here. So it's better to clarify
it before sending a v2. Do you mean to add something like:

patternProperties:
"^(thermocouple|diode|rtd|thermistor|adc|rsense)@([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

And then, for instance, for a RTD I would have:

patternProperties:
"^rtd@([2-9]|1[0-9]|20)$"

...

properties:
reg:
minimum: 2

...

Would this also make sense, or it's not really necessary?

patternProperties:
"^thermocouple@([1-9]|1[0-9]|20)$"
type: object

...

properties:
reg:
description: For differential thermocouples, the minimum is 2.

...

Am I understanding it correctly?
> > > +thermistor
> > > + 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.
>
> Any way we can make this real units? Can list valid value here.

For RTD's and diodes, it is possible to have it with real units.
However, for thermistors it's not really doable since, for instance,
for them we have an "Auto Range" setting. So, I just wanted to be
consistent through all sensors having excitation-current configuration.
Do you prefer to have it in real units where possible?

> > > + 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,l
> > > tc2983.yaml
> > >
> > > LTC4261 HARDWARE MONITOR DRIVER
> > > M: Guenter Roeck <linux@roeck-us.net>
> > > --
> > > 2.23.0
> > >