Date: Tue, 24 Nov 2015 18:01:30 -0600
From: Rob Herring <robh@kernel.org>
To: Adriana Reus <adriana.reus@intel.com>
Cc: jic23@kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        ijc+devicetree@hellion.org.uk, galak@codeaurora.org,
        pawel.moll@arm.com, pmeerw@pmeerw.net, lars@metafoo.de
Subject: Re: [PATCH 2/5] Documentation: devicetree: Add property for
 controlling power saving mode for the us5182 als sensor
Message-ID: <20151125000130.GA21418@rob-hp-laptop>
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On Tue, Nov 24, 2015 at 12:59:49PM +0200, Adriana Reus wrote:
> Add a property to allow changing the default power-saving mode.
> By default, at read raw the chip will activate and provide
> one measurent, then it will shut itself down. However, the
> chip can also work in "continuous" mode which may be more reliable
> but is also more power consuming.
> 
> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
> ---
>  Documentation/devicetree/bindings/iio/light/us5182d.txt | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/light/us5182d.txt b/Documentation/devicetree/bindings/iio/light/us5182d.txt
> index 6f0a530..a619799 100644
> --- a/Documentation/devicetree/bindings/iio/light/us5182d.txt
> +++ b/Documentation/devicetree/bindings/iio/light/us5182d.txt
> @@ -7,13 +7,24 @@ Required properties:
>  Optional properties:
>  - upisemi,glass-coef: glass attenuation factor - compensation factor of
>                        resolution 1000 for material transmittance.
> +
>  - upisemi,dark-ths: array of 8 elements containing 16-bit thresholds (adc
>                      counts) corresponding to every scale.
> +
>  - upisemi,upper-dark-gain: 8-bit dark gain compensation factor(4 int and 4
>                             fractional bits - Q4.4) applied when light > threshold
> +
>  - upisemi,lower-dark-gain: 8-bit dark gain compensation factor(4 int and 4
>                             fractional bits - Q4.4) applied when light < threshold
>  
> +- upisemi,continuous: This chip has two power modes: one-shot (chip takes one
> +                      measurement and then shuts itself down) and continuous (
> +                      chip takes continuous measurements). The one-shot mode is
> +                      more power-friendly but the continuous mode may be more
> +                      reliable. If this property is specified the continuous
> +                      mode will be used instead of the default one-shot one for
> +                      raw reads.

I could imagine an OS may want to decide this on its own or use a 
mixture of the modes.

Rob
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