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0c6db4506a
Add support for Texas Instruments OPT4060 RGBW Color sensor. Signed-off-by: Per-Daniel Olsson <perdaniel.olsson@axis.com> Link: https://patch.msgid.link/20241218104836.2784523-3-perdaniel.olsson@axis.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
62 lines
1.9 KiB
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62 lines
1.9 KiB
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==============================
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OPT4060 driver
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==============================
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1. Overview
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=============================
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This driver supports the Texas Instrument RGBW high resolution color sensor over
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I2C.
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https://www.ti.com/lit/gpn/opt4060
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The driver supports:
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- Raw values for red, green, blue and clear.
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- Illuminance values.
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- Scaled color values for red, green and blue.
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- IIO events for thresholds.
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- IIO triggered buffer using both its own data ready trigger and triggers from
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other drivers.
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2. Illuminance calculation
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=============================
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Illuminance is calculated using the wide spectrum green channel.
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lux = GREEN_RAW x 2.15e-3
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The value is accessed from:
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/sys/bus/iio/devices/iio:deviceX/in_illuminance_input
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See section 8.4.5.2 in the data sheet for additional details.
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3. Color scale values
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=============================
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The sensor has different sensitivity for the different color components and
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compensating factors are exposed from the driver.
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The values are accessed from:
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/sys/bus/iio/devices/iio:deviceX/in_intensity_red_scale
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/sys/bus/iio/devices/iio:deviceX/in_intensity_green_scale
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/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_scale
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A userspace application can multiply the raw values with the scale values so
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that for a particular test light source, typically white, the measurement
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intensity is the same across the different color channels. This is calculated
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in the following way:
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R = RED_RAW x SCALE_RED(2.4)
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G = GREEN_RAW x SCALE_GREEN(1.0)
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B = BLUE_RAW x SCALE_BLUE(1.3)
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The data sheet suggests using the scaled values to normalize the scaled R, G
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and B values. This is useful to get a value for the ratio between colors
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independent of light intensity. A userspace application can do this in the
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following way:
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R_NORMALIZED = R / (R + G + B)
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G_NORMALIZED = G / (R + G + B)
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B_NORMALIZED = B / (R + G + B)
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See section 8.4.5.2 in the data sheet for additional details.
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