[PATCH v2 7/8] staging: iio: isl29018: add ABI documentation for infrared suppression

Jonathan Cameron jic23 at kernel.org
Mon Oct 10 20:57:45 UTC 2016


On 10/10/16 08:20, Brian Masney wrote:
> Add ABI documentation from the ISL29018 Data Sheet (FN6619.4, Oct 8,
> 2012) about the infrared suppression that can be controlled
> with the proximity_on_chip_ambient_infrared_suppression sysfs attribute.
> 
> Signed-off-by: Brian Masney <masneyb at onstation.org>
I'm going to let this and the final move out of staging sit on the
list a while longer to gather reviews.

It does feel like the below is rather cryptic and it might be possible
to use a simpler description...  Maybe this is the best we can do.
The naming makes it sound generic, but in reality it's a nasty bit
of custom filtering that is not well described anywhere.

Jonathan
> ---
>  .../ABI/testing/sysfs-bus-iio-light-isl29018          | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-light-isl29018
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-light-isl29018 b/Documentation/ABI/testing/sysfs-bus-iio-light-isl29018
> new file mode 100644
> index 0000000..f0ce0a0
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-light-isl29018
> @@ -0,0 +1,19 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/proximity_on_chip_ambient_infrared_suppression
> +Date:		January 2011
> +KernelVersion:	2.6.37
> +Contact:	linux-iio at vger.kernel.org
> +Description:
> +		From ISL29018 Data Sheet (FN6619.4, Oct 8, 2012) regarding the
> +		infrared suppression:
> +
> +		Scheme 0, makes full n (4, 8, 12, 16) bits (unsigned) proximity
> +		detection. The range of Scheme 0 proximity count is from 0 to
> +		2^n. Logic 1 of this bit, Scheme 1, makes n-1 (3, 7, 11, 15)
> +		bits (2's complementary) proximity_less_ambient detection. The
> +		range of Scheme 1 proximity count is from -2^(n-1) to 2^(n-1).
> +		The sign bit is extended for resolutions less than 16. While
> +		Scheme 0 has wider dynamic range, Scheme 1 proximity detection
> +		is less affected by the ambient IR noise variation.
> +
> +		0 Sensing IR from LED and ambient
> +		1 Sensing IR from LED with ambient IR rejection
> 



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