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The integration_time sysfs attribute did not report the correct time. Changing the integration time would cause the reported lux to change wildly. Once the integration time was corrected, all of the equations, and lux tables needed to be corrected to match what the data sheets expected. This patch corrects all of this, and adds some more comments about how some of the constants were derived. Here are the results from testing a TSL2772 hooked up to a Raspberry Pi 2: # cat in_intensity0_integration_time 0.002730 # watch -n .1 cat in_illuminance0_input ; Lux hovers around 55 # echo 0.65 > in_intensity0_integration_time # cat in_intensity0_integration_time 0.649740 # watch -n .1 cat in_illuminance0_input ; Lux hovers around 55 with noticeable lag to lux changes in watch ; process. ; Now test the ALS calibration routine. # cat in_intensity0_calibbias 1000 # cat in_illuminance0_target_input 150 # echo 1 > in_illuminance0_calibrate # cat in_intensity0_calibbias 2777 # watch -n .1 cat in_illuminance0_input ; Lux now hovers around 150-155 The returned lux values were tested on a TSL2772 in various lighting conditions and the results are within the lux ranges described at https://en.wikipedia.org/wiki/Lux. The driver was primarily tested using a TSL2772, however some quick tests were also ran against the devices TSL2771, TSL2572, and TMD2772. Signed-off-by: Brian Masney <masneyb@onstation.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.