linux-kernel - Re: [PATCH v2 1/2] dt-bindings: iio: max30100: Add pulse-width property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251012180644.019616c9@jic23-huawei>
Date: Sun, 12 Oct 2025 18:06:44 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Shrikant Raskar <raskar.shree97@...il.com>
Cc: robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 dlechner@...libre.com, nuno.sa@...log.com, andy@...nel.org,
 matt@...ostay.sg, skhan@...uxfoundation.org, david.hunter.linux@...il.com,
 linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH v2 1/2] dt-bindings: iio: max30100: Add pulse-width
 property

On Wed,  8 Oct 2025 08:47:36 +0530
Shrikant Raskar <raskar.shree97@...il.com> wrote:

> The appropriate LED pulse width for the MAX30100 depends on
> board-specific optical and mechanical design (lens, enclosure,
> LED-to-sensor distance) and the trade-off between measurement
> resolution and power consumption. Encoding it in Device Tree
> documents these platform choices and ensures consistent behavior.
> 
> Tested on: Raspberry Pi 3B + MAX30100 breakout board.
> 
> Signed-off-by: Shrikant Raskar <raskar.shree97@...il.com>
> 
> Changes since v1:
> Add unit suffix.
> Drop redundant description.
> 
> Link to v1:
> https://lore.kernel.org/all/20251004015623.7019-2-raskar.shree97@gmail.com/
> ---
>  .../devicetree/bindings/iio/health/maxim,max30100.yaml      | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/health/maxim,max30100.yaml b/Documentation/devicetree/bindings/iio/health/maxim,max30100.yaml
> index 967778fb0ce8..5c651a0151cc 100644
> --- a/Documentation/devicetree/bindings/iio/health/maxim,max30100.yaml
> +++ b/Documentation/devicetree/bindings/iio/health/maxim,max30100.yaml
> @@ -27,6 +27,11 @@ properties:
>        LED current whilst the engine is running. First indexed value is
>        the configuration for the RED LED, and second value is for the IR LED.
>  
> +  maxim,pulse-width-us:
> +    maxItems: 1
> +    description: Pulse width in microseconds
I continued the discussion on v1 but just to make sure it is not
missed, add a bit more here briefly touching on factors that govern what
the right value is here.

Thanks,

Jonathan

> +    enum: [200, 400, 800, 1600]
> +
>  additionalProperties: false
>  
>  required:
> @@ -44,6 +49,7 @@ examples:
>              compatible = "maxim,max30100";
>              reg = <0x57>;
>              maxim,led-current-microamp = <24000 50000>;
> +            maxim,pulse-width-us = <1600>;
>              interrupt-parent = <&gpio1>;
>              interrupts = <16 2>;
>          };