linux-kernel - Re: [PATCH 1/2] dt-bindings: iio: chemical: Add sharp,gp2y1010au0f

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Message-ID: <20250426114725.27ab44bc@jic23-huawei>
Date: Sat, 26 Apr 2025 11:47:25 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: surajsonawane0215@...il.com
Cc: lars@...afoo.de, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: iio: chemical: Add sharp,gp2y1010au0f

On Sat, 26 Apr 2025 03:21:49 +0530
surajsonawane0215@...il.com wrote:

> From: Suraj Sonawane <surajsonawane0215@...il.com>
Hi Suraj,

Welcome to IIO.

> 
> Add Device Tree bindings for Sharp GP2Y1010AU0F optical dust sensor.
> The sensor measures particulate matter concentration via infrared
> scattering and requires:
> 
> 1. GPIO for LED pulse control (280μs pulses with 40μs delay)
> 2. ADC channel for analog output measurement
> 3. Power regulator (vdd-supply)
> 
> Datasheet:
> https://global.sharp/products/device/lineup/data/pdf/datasheet/gp2y1010au_appl_e.pdf
This can be a tag, so put it all on one line and drop this blank line so it forms
part of the tag block.  Don't worry about checkpatch warning that will result.
It never got updated for Datasheet: properly.
> 
> Signed-off-by: Suraj Sonawane <surajsonawane0215@...il.com>
> ---
>  .../iio/chemical/sharp,gp2y1010au0f.yaml      | 67 +++++++++++++++++++
>  1 file changed, 67 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/chemical/sharp,gp2y1010au0f.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/chemical/sharp,gp2y1010au0f.yaml b/Documentation/devicetree/bindings/iio/chemical/sharp,gp2y1010au0f.yaml
> new file mode 100644
> index 000000000..358c2b2f7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/chemical/sharp,gp2y1010au0f.yaml
> @@ -0,0 +1,67 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/chemical/sharp,gp2y1010au0f.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Sharp GP2Y1010AU0F Optical Dust Sensor
> +
> +maintainers:
> +  - Suraj Sonawane <surajsonawane0215@...il.com>
> +
> +description: |
> +  Optical dust sensor measuring particulate matter concentration via infrared scattering.
> +  Requires ADC for analog output and GPIO for pulsed LED control with strict timing.
> +  Datasheet: https://global.sharp/products/device/lineup/data/pdf/datasheet/gp2y1010au_appl_e.pdf
> +
> +properties:
> +  compatible:
> +    const: sharp,gp2y1010au0f
> +
> +  vdd-supply:
> +    description: Phandle to the regulator that provides power to the sensor

For a simple supply voltage no real need for the docs.
    vdd-supply: true
is usually enough.

> +
> +  led-gpios:
> +    description: GPIO connected to the sensor's LED control pin (V-LED)
> +    maxItems: 1
> +
> +  io-channels:
> +    description: ADC channel connected to the sensor's analog output (Vo)
> +    maxItems: 1
> +
> +  io-channel-names:
> +    const: dust
> +
> +  sharp,led-on-delay-us:
> +    description: Time in microseconds to wait after turning LED on before ADC read

The datasheet seems to suggest a 0.28msec value for this for an LED pulse width of
0.32msecs

Hence maybe you could give a spec reference for the range given here?  I may well
be looking at the wrong bit of the datasheet!

> +    default: 40
> +    minimum: 0
> +    maximum: 100
> +
> +  sharp,measurement-window-us:
> +    description: Measurement window in microseconds after LED turn-on

I'm not able to directly relate this to what I'm seeing on the datasheet.
Is this just the on time?

> +    default: 200
> +    minimum: 0
> +    maximum: 280
> +
> +required:
> +  - compatible
> +  - led-gpios
> +  - io-channels
> +  - io-channel-names
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    dust_sensor {
I think this needs a reg, even if that is just an index so we can keep track of multiple sensors.

> +        compatible = "sharp,gp2y1010au0f";
> +        vdd-supply = <&vcc>;
> +        led-gpios = <&gpio 44 GPIO_ACTIVE_HIGH>;
> +        io-channels = <&adc 0>;
> +        io-channel-names = "dust";
> +        sharp,led-on-delay-us = <40>;
> +        sharp,measurement-window-us = <200>;	
> +    };