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| author | Brian Masney <masneyb@onstation.org> | 2016-10-07 03:48:34 +0300 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2016-10-11 21:40:26 +0300 |
| commit | e748e2801a70eb0da6dbc2db1407185a2883533d (patch) | |
| tree | e801b12a7413665dc9c6c6a3727655aed0d69632 | |
| parent | 88efa2baf15a5766c6b9cc29e60761b441cec170 (diff) | |
| download | linux-e748e2801a70eb0da6dbc2db1407185a2883533d.tar.xz | |
staging: iio: isl29018: add documentation about the infrared suppression
Add 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@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
| -rw-r--r-- | drivers/staging/iio/light/isl29018.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c index 51226bd337c5..52bfb1cbe8e0 100644 --- a/drivers/staging/iio/light/isl29018.c +++ b/drivers/staging/iio/light/isl29018.c @@ -307,6 +307,24 @@ static ssize_t in_illuminance_integration_time_available_show return len; } +/* + * From ISL29018 Data Sheet (FN6619.4, Oct 8, 2012) regarding the + * infrared suppression: + * + * Proximity Sensing Scheme: Bit 7. This bit programs the function + * of the proximity detection. Logic 0 of this bit, 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 + */ static ssize_t proximity_on_chip_ambient_infrared_suppression_show (struct device *dev, struct device_attribute *attr, char *buf) |