88ba95bedb
When you want to change the brightness using a PWM signal, one thing you need to consider is how human perceive the brightness. Human perceive the brightness change non-linearly, we have better sensitivity at low luminance than high luminance, so to achieve perceived linear dimming, the brightness must be matches to the way our eyes behave. The CIE 1931 lightness formula is what actually describes how we perceive light. This patch computes a default table with the brightness levels filled with the numbers provided by the CIE 1931 algorithm, the number of the brightness levels is calculated based on the PWM resolution. The calculation of the table using the CIE 1931 algorithm is enabled by default when you do not define the 'brightness-levels' propriety in your device tree. Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.