linux-kernel - Re: [PATCH v2 2/2] dt-bindings: iio: adc: devicetree bindings for texas instruments ads7142

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Message-ID: <20210516123027.GA16211@dev>
Date:   Sun, 16 May 2021 12:30:28 +0000
From:   József Horváth <info@...istro.hu>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Alexandru Ardelean <aardelean@...iqon.com>,
        Alexandru Ardelean <ardeleanalex@...il.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Oleksij Rempel <linux@...pel-privat.de>,
        Saravanan Sekar <sravanhome@...il.com>,
        Tomislav Denis <tomislav.denis@....com>,
        Gene Chen <gene_chen@...htek.com>,
        Alex Dewar <alex.dewar90@...il.com>,
        Lee Jones <lee.jones@...aro.org>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 2/2] dt-bindings: iio: adc: devicetree bindings for
 texas instruments ads7142

Hi Jonathan,

On Sun, May 16, 2021 at 10:57:20AM +0100, Jonathan Cameron wrote:
> On Sun, 16 May 2021 07:31:05 +0000
> Jozsef Horvath <info@...istro.hu> wrote:
> 
> > This is a device tree schema for iio driver for
> >  Texas Instruments ADS7142 dual-channel, programmable sensor monitor.
> > 
> > Datasheet: https://www.ti.com/lit/ds/symlink/ads7142.pdf
> > 
> > Signed-off-by: Jozsef Horvath <info@...istro.hu>
> 
> Hi József,
> 
> A few comments inline.
> 
> thanks,
> 
> Jonathan
> > ---
> > 
> > changes v1
> >   - Redundant parameters (ti,threshold-rising, etc.)
> >     are removed
> >   - Supply name changed(vref -> avdd)
> >   - Added dvdd supply
> >   - All the properties are removed with prefix "ti,"
> > changes v2
> >   - "ti,prealert-count" parameter added, just for completeness.
> > ---
> >  .../bindings/iio/adc/ti,ads7142.yaml          | 110 ++++++++++++++++++
> >  1 file changed, 110 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,ads7142.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads7142.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads7142.yaml
> > new file mode 100644
> > index 000000000000..6e52079c68f7
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads7142.yaml
> > @@ -0,0 +1,110 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: "http://devicetree.org/schemas/iio/adc/ti,ads7142.yaml#"
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > +
> > +title: Texas Instruments ADS7142 adc driver device tree bindings
> 
> ADC
> 
> > +
> > +maintainers:
> > +  - József Horváth <info@...istro.hu>
> > +
> > +description: |
> > +  This document is for describing the required device tree parameters
> > +   for ads7142 adc
> 
> ADC
> 
> > +  The required parameters for proper operation are described below.
> > +
> > +  Datasheet: https://www.ti.com/lit/ds/symlink/ads7142.pdf
> > +
> > +properties:
> > +  compatible:
> > +    const: ti,ads7142
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    description: |
> > +      The BUSY/PDY pin is used as interrupt line
> 
> RDY ?

I'll fix these typos in v3

> 
> > +       in autonomous monitoring mode.
> > +    maxItems: 1
> > +
> > +  avdd-supply:
> > +    description: Regulator for the reference voltage
> > +
> > +  dvdd-supply: true
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#size-cells":
> > +    const: 0
> > +
> > +  "#io-channel-cells":
> > +    const: 1
> > +
> > +  ti,prealert-count:
> > +    description: |
> > +      Sets the Pre-Alert Event Count for both,
> > +       high and low comparators, for both the channels.
> 
> Interesting.  Why is this a device tree property rather than something
> we want to configure from userspace?  Looks like it would map to _period
> after scaling by the sampling frequency.
> 
> https://elixir.bootlin.com/linux/latest/source/Documentation/ABI/testing/sysfs-bus-iio#L1003
> 
> 

Ok, I'll try to bring it to sysfs as you suggested

> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    maximum: 15
> > +    minimum: 0
> > +
> > +patternProperties:
> > +  "^channel@[0-1]$":
> > +    $ref: "adc.yaml"
> > +    type: object
> > +    description: |
> > +      Represents the external channels which are connected to the ADC.
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number.
> > +        items:
> > +          minimum: 0
> > +          maximum: 1
> 
> enum: [0 1]
> is a more compact way of putting this IIRC.
>  

I'll do that

> > +
> > +    required:
> > +      - reg
> > +
> > +    additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - "#io-channel-cells"
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    i2c {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +      adc@1f {
> > +        compatible = "ti,ads7142";
> > +        reg = <0x1f>;
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        #io-channel-cells = <1>;
> > +
> > +        avdd-supply = <&vdd_3v3_reg>;
> > +        dvdd-supply = <&vdd_1v8_reg>;
> > +
> > +        interrupt-parent = <&gpio>;
> > +        interrupts = <7 2>;
> > +
> > +        ti,prealert-count = <4>;
> > +
> > +        channel@0 {
> > +          reg = <0>;
> > +        };
> > +
> > +        channel@1 {
> > +          reg = <1>;
> > +        };
> > +      };
> > +    };
> > +...
> > +
> 

Thank you.

Best regards
József