Re: [PATCH 1/3] dt-bindings: iio: adc: add support for AD5940

From: Song Qiang
Date: Thu Nov 14 2019 - 08:32:26 EST

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In reply to: Jonathan Cameron: "Re: [PATCH 1/3] dt-bindings: iio: adc: add support for AD5940"
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On 11/11/19 12:26 AM, Jonathan Cameron wrote:
> On Fri, 8 Nov 2019 21:09:44 +0800
> Song Qiang <songqiang1304521@xxxxxxxxx> wrote:
>
>> Add yaml devicetree description file and a header file for
>> helping configure positive and negtive input of AD5940.
>>
>> Signed-off-by: Song Qiang <songqiang1304521@xxxxxxxxx>
> Ouch. This is a very complex device, so I'm guessing this is the tip
> of the iceberg when it comes to the eventual binding.
> For reference of others this has a similarly complex DAC and
> TIA + some excitation voltage generators (DDS).
>
> Anyhow, a few comments inline but I'll definitely be looking for
> a dt maintainer input on this one.
>
> Thanks,
>
> Jonathan
>

Thanks, this is the first part support of the driver.

>> ---
>> .../bindings/iio/adc/adi,ad5940.yaml | 240 ++++++++++++++++++
>> include/dt-bindings/iio/adc/adi,ad5940.h | 52 ++++
>> 2 files changed, 292 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad5940.yaml
>> create mode 100644 include/dt-bindings/iio/adc/adi,ad5940.h
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad5940.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad5940.yaml
>> new file mode 100644
>> index 000000000000..f7f034fdd8ec
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad5940.yaml
>> @@ -0,0 +1,240 @@
>> +# SPDX-License-Identifier: GPL-2.0
> For new bindings, preference is to include a dual license
> (GPL-2.0-only OR BSD-2-Clause)
>
> If Analog is fine doing this that would be great.
>

I'll consult my mentor about this.

>> +# Copyright 2019 Analog Devices Inc.
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/bindings/iio/adc/adi,ad5940.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Analog Devices AD5940 Device Tree Bindings
>> +
>> +maintainers:
>> + - Song Qiang <songqiang1304521@xxxxxxxxx>
>> +
>> +description: |
>> + Analog Devices AD5940 High Precision, Impedance, and Electrochemical Front End.
>> + https://www.analog.com/media/en/technical-documentation/data-sheets/AD5940.pdf
>> +
>> +properties:
>> + compatible:
>> + enum:
>> + - adi,ad5940
>> +
>> + reg:
>> + maxItems: 1
>> +
>> + vref-supply:
>> + description:
>> + The regulator to be used to supply the reference voltage.
>> + maxItems: 1
>
> It's worth taking a look at similar patch reviews to pick up on things
> that are common issues. Rob has pointed out a few times recently that
> vref-supply can only ever have one item, so no need for maxItems.
>

That's right, thanks.

>> +
>> + adi,interrupt-io:
>> + description:
>> + Output GPIO index of interrupt controller of AD5940.
>> + maxItems: 1
>
> I'm fairly sure an enum can only have one entry so don't think this is
> needed.
>
>> + allOf:
>> + - $ref: /schemas/types.yaml#/definitions/uint32
>> + - enum: [0, 3, 6, 7]
>> +
>> + '#address-cells':
>> + const: 1
>> +
>> + '#size-cells':
>> + const: 0
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - interrupts
>> + - adi,interrupt-io
>> +
>> +patternProperties:
>> + # 'channel@0-255'
>
> Really? That is a lot of channels. Superficially it looks like a much
> smaller number of possibilities from the datasheet.
>

This device has some positive inputs and some negative inputs. A channel
here is a combination of one positive input and one negative input.
These channels I listed in examples are only suggested combinations in
the datasheet, while other combinations are all possible. So I was
thinking to not limit the total count of channels here. I failed to find
examples of doing this kind of stuff in the tree.

yours,
Song Qiang

>> + "^channel@([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])$":
>> + type: object
>> + description: |
>> + Represents the external channels which are connected to the ADC.
>> + See Documentation/devicetree/bindings/iio/adc/adc.txt.
>> + properties:
>> + reg:
>> + description:
>> + Index of this channel, must be starting from 0.
>> + maxItems: 1
>> +
>> + diff-channels:
>> + description:
>> + Positive input and negtive input of the ADC buffer of this channel.
>> + Input candidates are defined in include/dt-bindings/iio/adc/adi,ad5940.h.
>> + minItems: 2
>> + maxItems: 2
>> + items:
>> + - description: Positive input channel
>> + - enum:
>> + - AD5940_ADC_INPUTP_EXCITATION
>> + - AD5940_ADC_INPUTP_FLOATING
>> + - AD5940_ADC_INPUTP_HSTIA
>> + - AD5940_ADC_INPUTP_LPTIA_LP
>> + - AD5940_ADC_INPUTP_AIN0
>> + - AD5940_ADC_INPUTP_AIN1
>> + - AD5940_ADC_INPUTP_AIN2
>> + - AD5940_ADC_INPUTP_AIN3
>> + - AD5940_ADC_INPUTP_AVDD_2
>> + - AD5940_ADC_INPUTP_DVDD_2
>> + - AD5940_ADC_INPUTP_AVDD_REG_2
>> + - AD5940_ADC_INPUTP_TEMP
>> + - AD5940_ADC_INPUTP_VBIAS_CAP
>> + - AD5940_ADC_INPUTP_DE0
>> + - AD5940_ADC_INPUTP_SE0
>> + - AD5940_ADC_INPUTP_VREF_2V5_2
>> + - AD5940_ADC_INPUTP_VREF_1V82
>> + - AD5940_ADC_INPUTP_P_TEMP_N
>> + - AD5940_ADC_INPUTP_AIN4
>> + - AD5940_ADC_INPUTP_AIN6
>> + - AD5940_ADC_INPUTP_VZERO
>> + - AD5940_ADC_INPUTP_VBIAS0
>> + - AD5940_ADC_INPUTP_VCE0
>> + - AD5940_ADC_INPUTP_VRE0
>> + - AD5940_ADC_INPUTP_VCE0_2
>> + - AD5940_ADC_INPUTP_LPTIA
>> + - AD5940_ADC_INPUTP_AGND_REF
>> +
>> + - description: Negtive input channel
>> + - enum:
>> + # Negtive input candidates
>> + - AD5940_ADC_INPUTN_FLOATING
>> + - AD5940_ADC_INPUTN_HSTIA
>> + - AD5940_ADC_INPUTN_LPTIA
>> + - AD5940_ADC_INPUTN_AIN0
>> + - AD5940_ADC_INPUTN_AIN1
>> + - AD5940_ADC_INPUTN_AIN2
>> + - AD5940_ADC_INPUTN_AIN3
>> + - AD5940_ADC_INPUTN_VBIAS_CA8
>> + - AD5940_ADC_INPUTN_TEMP_N
>> + - AD5940_ADC_INPUTN_AIN4
>> + - AD5940_ADC_INPUTN_AIN6
>> + - AD5940_ADC_INPUTN_VZERO
>> + - AD5940_ADC_INPUTN_VBIAS0
>> + - AD5940_ADC_INPUTN_EXCITATION
>> +
>> + channel-name:
>> + description:
>> + Any string format name you would like to assign to this channel.
>> + maxItems: 1
>> +
>> + required:
>> + - reg
>> + - diff-channels
>> + - channel-name
>> +
>> +examples:
>> + - |
>> + ad5940: ad5940@0 {
>> + compatible = "adi,ad5940";
>> + reg = <0>;
>> + spi-max-frequency = <16000000>;
>> + vref-supply = <&adc_vref>;
>> + interrupt-parent = <&gpio>;
>> + interrupts = <24 2>;
>> +
>> + adi,interrupt-io = <0>;
>> +
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> +
>> + channel@0 {
>> + reg = <0>;
>> + diff-channels = <AD5940_ADC_INPUTP_VCE0
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "Vce-Vbias";
>> + };
>> +
>> + channel@1 {
>> + reg = <1>;
>> + diff-channels = <AD5940_ADC_INPUTP_VRE0
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "Vre-Vbias";
>> + };
>> +
>> + channel@2 {
>> + reg = <2>;
>> + diff-channels = <AD5940_ADC_INPUTP_SE0
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "Vse-Vbias";
>> + };
>> +
>> + channel@3 {
>> + reg = <3>;
>> + diff-channels = <AD5940_ADC_INPUTP_DE0
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "Vde-Vbias";
>> + };
>> +
>> + channel@4 {
>> + reg = <4>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN0
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain0-Vbias";
>> + };
>> +
>> + channel@5 {
>> + reg = <5>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN1
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain1-Vbias";
>> + };
>> +
>> + channel@6 {
>> + reg = <6>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN2
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain2-Vbias";
>> + };
>> +
>> + channel@7 {
>> + reg = <7>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN3
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain3-Vbias";
>> + };
>> +
>> + channel@8 {
>> + reg = <8>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN4
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain4-Vbias";
>> + };
>> +
>> + channel@9 {
>> + reg = <9>;
>> + diff-channels = <AD5940_ADC_INPUTP_AIN6
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "ain6-Vbias";
>> + };
>> +
>> + channel@10 {
>> + reg = <10>;
>> + diff-channels = <AD5940_ADC_INPUTP_LPTIA_LP
>> + AD5940_ADC_INPUTN_LPTIA>;
>> + channel-name = "Low power TIA DC";
>> + };
>> +
>> + channel@11 {
>> + reg = <11>;
>> + diff-channels = <AD5940_ADC_INPUTP_LPTIA
>> + AD5940_ADC_INPUTN_LPTIA>;
>> + channel-name = "Low power TIA AC";
>> + };
>> +
>> + channel@12 {
>> + reg = <12>;
>> + diff-channels = <AD5940_ADC_INPUTP_HSTIA
>> + AD5940_ADC_INPUTN_HSTIA>;
>> + channel-name = "High Speed TIA";
>> + };
>> +
>> + channel@13 {
>> + reg = <13>;
>> + diff-channels = <AD5940_ADC_INPUTP_TEMP
>> + AD5940_ADC_INPUTN_VBIAS0>;
>> + channel-name = "Temperature";
>> + };
>> + };
>> diff --git a/include/dt-bindings/iio/adc/adi,ad5940.h b/include/dt-bindings/iio/adc/adi,ad5940.h
>> new file mode 100644
>> index 000000000000..c17826f2f654
>> --- /dev/null
>> +++ b/include/dt-bindings/iio/adc/adi,ad5940.h
>> @@ -0,0 +1,52 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * This header provides constants for configuring the AD5940 AFE
>> + */
>> +
>> +#ifndef _DT_BINDINGS_IIO_ADC_AD5940_H
>> +#define _DT_BINDINGS_IIO_ADC_AD5940_H
>> +
>> +#define AD5940_ADC_INPUTN_FLOATING 0
>> +#define AD5940_ADC_INPUTN_HSTIA 1
>> +#define AD5940_ADC_INPUTN_LPTIA 2
>> +#define AD5940_ADC_INPUTN_AIN0 4
>> +#define AD5940_ADC_INPUTN_AIN1 5
>> +#define AD5940_ADC_INPUTN_AIN2 6
>> +#define AD5940_ADC_INPUTN_AIN3 7
>> +#define AD5940_ADC_INPUTN_VBIAS_CA8 10
>> +#define AD5940_ADC_INPUTN_TEMP_N 11
>> +#define AD5940_ADC_INPUTN_AIN4 12
>> +#define AD5940_ADC_INPUTN_AIN6 14
>> +#define AD5940_ADC_INPUTN_VZERO 16
>> +#define AD5940_ADC_INPUTN_VBIAS0 17
>> +#define AD5940_ADC_INPUTN_EXCITATION 20
>> +
>> +#define AD5940_ADC_INPUTP_FLOATING 0
>> +#define AD5940_ADC_INPUTP_HSTIA 1
>> +#define AD5940_ADC_INPUTP_LPTIA_LP 2
>> +#define AD5940_ADC_INPUTP_AIN0 4
>> +#define AD5940_ADC_INPUTP_AIN1 5
>> +#define AD5940_ADC_INPUTP_AIN2 6
>> +#define AD5940_ADC_INPUTP_AIN3 7
>> +#define AD5940_ADC_INPUTP_AVDD_2 8
>> +#define AD5940_ADC_INPUTP_DVDD_2 9
>> +#define AD5940_ADC_INPUTP_AVDD_REG_2 10
>> +#define AD5940_ADC_INPUTP_TEMP 11
>> +#define AD5940_ADC_INPUTP_VBIAS_CAP 12
>> +#define AD5940_ADC_INPUTP_DE0 13
>> +#define AD5940_ADC_INPUTP_SE0 14
>> +#define AD5940_ADC_INPUTP_VREF_2V5_2 16
>> +#define AD5940_ADC_INPUTP_VREF_1V82 18
>> +#define AD5940_ADC_INPUTP_P_TEMP_N 19
>> +#define AD5940_ADC_INPUTP_AIN4 20
>> +#define AD5940_ADC_INPUTP_AIN6 22
>> +#define AD5940_ADC_INPUTP_VZERO 23
>> +#define AD5940_ADC_INPUTP_VBIAS0 24
>> +#define AD5940_ADC_INPUTP_VCE0 25
>> +#define AD5940_ADC_INPUTP_VRE0 26
>> +#define AD5940_ADC_INPUTP_VCE0_2 31
>> +#define AD5940_ADC_INPUTP_LPTIA 33
>> +#define AD5940_ADC_INPUTP_AGND_REF 35
>> +#define AD5940_ADC_INPUTP_EXCITATION 36
>> +
>> +#endif /* _DT_BINDINGS_IIO_ADC_AD5940 */
>

Next message: Dan Murphy: "[PATCH v17 12/19] leds: lp55xx: Convert LED class registration to devm_*"
Previous message: Dan Murphy: "[PATCH v17 08/19] dt: bindings: lp55xx: Update binding for Multicolor Framework"
In reply to: Jonathan Cameron: "Re: [PATCH 1/3] dt-bindings: iio: adc: add support for AD5940"
Next in thread: Ardelean, Alexandru: "Re: [PATCH 1/3] dt-bindings: iio: adc: add support for AD5940"
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