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Message-ID: <ZXMZ-Y18SwIFEIgA@debian-BULLSEYE-live-builder-AMD64>
Date: Fri, 8 Dec 2023 10:28:25 -0300
From: Marcelo Schmitt <marcelo.schmitt1@...il.com>
To: David Lechner <dlechner@...libre.com>
Cc: Marcelo Schmitt <marcelo.schmitt@...log.com>, apw@...onical.com,
joe@...ches.com, dwaipayanray1@...il.com, lukas.bulwahn@...il.com,
paul.cercueil@...log.com, Michael.Hennerich@...log.com,
lars@...afoo.de, jic23@...nel.org, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
dan.carpenter@...aro.org, linux-iio@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 10/13] dt-bindings: iio: Add AD7091R-8
Hi David, thank you for your suggestions.
Comments inline.
On 12/07, David Lechner wrote:
> On Thu, Dec 7, 2023 at 12:42 PM Marcelo Schmitt
> <marcelo.schmitt@...log.com> wrote:
> >
> > Add device tree documentation for AD7091R-8.
> >
> > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@...log.com>
> > ---
> > .../bindings/iio/adc/adi,ad7091r8.yaml | 99 +++++++++++++++++++
> > 1 file changed, 99 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7091r8.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7091r8.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7091r8.yaml
> > new file mode 100644
> > index 000000000000..02320778f225
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7091r8.yaml
> > @@ -0,0 +1,99 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/adi,ad7091r8.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Analog Devices AD7091R8 8-Channel 12-Bit ADC
> > +
> > +maintainers:
> > + - Marcelo Schmitt <marcelo.schmitt@...log.com>
> > +
> > +description: |
> > + Analog Devices AD7091R-8 8-Channel 12-Bit ADC
> > + https://www.analog.com/media/en/technical-documentation/data-sheets/AD7091R-2_7091R-4_7091R-8.pdf
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - adi,ad7091r2
> > + - adi,ad7091r4
> > + - adi,ad7091r8
> > +
> > + reg:
> > + maxItems: 1
> > +
>
> Missing other supplies? Like vdd-supply and vdrive-supply?
>
I used the name that would work with ad7091r-base.c.
If I'm not misinterpreting the datasheet, vdd-supply and vdrive-supply are
for powering the ADC and setting SPI lanes logic level, respectively.
They don't have any impact on ADC readings.
By the way, should maybe I extend ad7091r5 dt doc instead of creating this
new one?
> > + vref-supply: true
>
> refin-supply might be a better name to match the datasheet pin name.
>
Agree, though I guess changing the name now would break users of ad7091r5 if
they happen to update the driver without updating their device tree.
> > +
> > + adi,conversion-start-gpios:
>
> gpios usually don't get a vendor prefix do they?
>
> convst-gpios could be a better name to match the pin name on the datasheet.
Ack, will do for v4.
>
> > + description:
> > + GPIO connected to the CONVST pin.
> > + This logic input is used to initiate conversions on the analog
> > + input channels.
> > + maxItems: 1
> > +
> > + reset-gpios:
> > + maxItems: 1
> > +
> > + interrupts:
> > + maxItems: 1
>
> A description of what the interrupt is attached to (ALERT/BUSY/GPO0
> pin) would be helpful.
>
Ack, will do for v4.
> > +
> > +patternProperties:
> > + "^channel@[0-7]$":
> > + $ref: adc.yaml
> > + type: object
> > + description: Represents the external channels which are connected to the ADC.
> > +
> > + properties:
> > + reg:
> > + minimum: 0
> > + maximum: 7
>
> Shouldn't this be:
>
> items:
> - minimum: 0
> maximum: 7
>
Ack
> > +
> > + required:
> > + - reg
>
> Missing `unevaluatedProperties: false` for channels?
>
> Bigger picture: since no other properties besides `reg` are included
> here, do we actually need channel nodes?
>
The channel nodes are not used by the drivers so we can remove them if we want.
I thought they would be required as documentation even if they were not used
in drivers.
Looks like they're not required so will remove them in v4.
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - adi,conversion-start-gpios
> > +
> > +allOf:
> > + - $ref: /schemas/spi/spi-peripheral-props.yaml#
> > +
> > + # AD7091R-2 does not have ALERT/BUSY/GPO pin
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - adi,ad7091r4
> > + - adi,ad7091r8
> > + then:
> > + properties:
> > + interrupts: true
>
> Interrupts is already true. Maybe better to only match chips without
> interrupts and set false?
>
Agree, that should simplify the constrain logic. Will do for v4.
> > + else:
> > + properties:
> > + interrupts: false
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/interrupt-controller/irq.h>
> > + #include <dt-bindings/gpio/gpio.h>
> > + spi {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + adc@0 {
> > + compatible = "adi,ad7091r8";
> > + reg = <0x0>;
> > + spi-max-frequency = <45454545>;
> > + vref-supply = <&adc_vref>;
> > + adi,conversion-start-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
> > + reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
> > + interrupts = <22 IRQ_TYPE_EDGE_FALLING>;
> > + interrupt-parent = <&gpio>;
> > + };
> > + };
> > +...
> > --
> > 2.42.0
> >
> >
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