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Sam Ravnborg
1c91b46555
backlight: backlight: Add backlight_is_blank()
The backlight support has three properties that express the state: - power - state - fb_blank It is un-documented and easy to get wrong. Add backlight_is_blank() helper to make it simpler for drivers to get the check of the state correct. A lot of drivers also includes checks for fb_blank. This check is redundant when the state is checked and thus not needed in this helper function. But added anyway to avoid introducing subtle bugs due to the creative use of fb_blank in some drivers. Introducing this helper will for some drivers results in added support for fb_blank. This will be a change in functionality, which will improve the backlight driver. Rolling out this helper to all relevant backlight drivers will eliminate almost all accesses to fb_blank. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> 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. 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.
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