diff options
Diffstat (limited to 'Documentation/iio/opt4060.rst')
| -rw-r--r-- | Documentation/iio/opt4060.rst | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/Documentation/iio/opt4060.rst b/Documentation/iio/opt4060.rst new file mode 100644 index 000000000000..eb155089b6d2 --- /dev/null +++ b/Documentation/iio/opt4060.rst @@ -0,0 +1,61 @@ +============================== +OPT4060 driver +============================== + +1. Overview +============================= + +This driver supports the Texas Instrument RGBW high resolution color sensor over +I2C. +https://www.ti.com/lit/gpn/opt4060 + +The driver supports: +- Raw values for red, green, blue and clear. +- Illuminance values. +- Scaled color values for red, green and blue. +- IIO events for thresholds. +- IIO triggered buffer using both its own data ready trigger and triggers from +other drivers. + +2. Illuminance calculation +============================= + +Illuminance is calculated using the wide spectrum green channel. + +lux = GREEN_RAW x 2.15e-3 + +The value is accessed from: +/sys/bus/iio/devices/iio:deviceX/in_illuminance_input + +See section 8.4.5.2 in the data sheet for additional details. + +3. Color scale values +============================= + +The sensor has different sensitivity for the different color components and +compensating factors are exposed from the driver. + +The values are accessed from: +/sys/bus/iio/devices/iio:deviceX/in_intensity_red_scale +/sys/bus/iio/devices/iio:deviceX/in_intensity_green_scale +/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_scale + +A userspace application can multiply the raw values with the scale values so +that for a particular test light source, typically white, the measurement +intensity is the same across the different color channels. This is calculated +in the following way: + +R = RED_RAW x SCALE_RED(2.4) +G = GREEN_RAW x SCALE_GREEN(1.0) +B = BLUE_RAW x SCALE_BLUE(1.3) + +The data sheet suggests using the scaled values to normalize the scaled R, G +and B values. This is useful to get a value for the ratio between colors +independent of light intensity. A userspace application can do this in the +following way: + +R_NORMALIZED = R / (R + G + B) +G_NORMALIZED = G / (R + G + B) +B_NORMALIZED = B / (R + G + B) + +See section 8.4.5.2 in the data sheet for additional details. |