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@xxxxxxxxxxxxx> --- drivers/staging/iio/light/isl29018.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c index 51226bd..52bfb1cb 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) -- 2.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
