xref: /openbmc/linux/Documentation/ABI/testing/sysfs-bus-iio-light-isl29018 (revision af06437dae78cc61d89f528fa4a121c27c50bc55)
1*af06437dSBrian MasneyWhat:		/sys/bus/iio/devices/iio:deviceX/proximity_on_chip_ambient_infrared_suppression
2*af06437dSBrian MasneyDate:		January 2011
3*af06437dSBrian MasneyKernelVersion:	2.6.37
4*af06437dSBrian MasneyContact:	linux-iio@vger.kernel.org
5*af06437dSBrian MasneyDescription:
6*af06437dSBrian Masney		From ISL29018 Data Sheet (FN6619.4, Oct 8, 2012) regarding the
7*af06437dSBrian Masney		infrared suppression:
8*af06437dSBrian Masney
9*af06437dSBrian Masney		Scheme 0, makes full n (4, 8, 12, 16) bits (unsigned) proximity
10*af06437dSBrian Masney		detection. The range of Scheme 0 proximity count is from 0 to
11*af06437dSBrian Masney		2^n. Logic 1 of this bit, Scheme 1, makes n-1 (3, 7, 11, 15)
12*af06437dSBrian Masney		bits (2's complementary) proximity_less_ambient detection. The
13*af06437dSBrian Masney		range of Scheme 1 proximity count is from -2^(n-1) to 2^(n-1).
14*af06437dSBrian Masney		The sign bit is extended for resolutions less than 16. While
15*af06437dSBrian Masney		Scheme 0 has wider dynamic range, Scheme 1 proximity detection
16*af06437dSBrian Masney		is less affected by the ambient IR noise variation.
17*af06437dSBrian Masney
18*af06437dSBrian Masney		0 Sensing IR from LED and ambient
19*af06437dSBrian Masney		1 Sensing IR from LED with ambient IR rejection
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