Re: [PATCH v3 1/2] dt-bindings: iio: health: max30100: Add LED pulse-width property

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/10/2025 19:30, Shrikant Raskar wrote:
> The LED pulse width on the MAX30100 sensor determines how long the
> IR/Red LEDs are driven during each sample, directly affecting the
> emitted optical energy and hence the received signal amplitude.
> 
> This parameter is highly dependent on the mechanical and optical
> integration of the sensor, such as:
> - The type and thickness of the optical window or lens covering
>   the sensor.
> - The distance between the LED and photodiode.
> - The reflectivity of the target surface.
> 
> For example:
> - A smartwatch or wearable ring with a thin glass window can operate
>   with shorter pulses (200-400 us) to save power.
> - A medical-grade pulse oximeter or sensor mounted behind a thicker
>   protective layer may require longer pulses (800-1600 us) for
>   reliable signal amplitude.
> 
> Because this configuration is determined by hardware design rather than
> by runtime conditions, it is appropriate to describe it in the DT.
> 
> If not specified, the driver defaults to 1600 us to maintain
> existing behavior.
> 
> Tested on: Raspberry Pi 3B + MAX30100 breakout board.
> 
> Signed-off-by: Shrikant Raskar <raskar.shree97@gmail.com>

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof