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The ADV7604, ADV7611 and ADV7612 software manuals document the CP_HUE value differently: - For ADV7604 and ADV7611, the hue is specified as an unsigned 8-bit value, and calculated as (CP_HUE[7:0] * 180) / 256 - 90 with the range set to [-90°, 90°]. Additionally, the values 0x00, 0x0f and 0xff are documented as corresponding to -90°, 0° and 90° respectively. - For ADV7612, the hue is specified as a signed 8-bit value in the range [0°, 360°[ without any formula. Additionally, the value 0x00 is documented as corresponding to 0°. The ADV7604 and ADV7611 documentation is clearly wrong as the example values don't correspond to the formula. Furthermore, the [-90°, 90°] range seems incorrect as it would cover only half of the hue space. The ADV7612 documentation is better, although the range should likely be [-180°, 180°[ if the value is signed. Given that the values wrap around, this makes no difference in practice. The hue values have been verified on ADV7612 to follow the documentation. There is a high chance they do as well on ADV7604 and ADV7611. In any case, all software manuals document the register as 8-bit, so the current range of the V4L2 hue control [0, 128] is not correct. Expand it to cover the full 8-bit space, using unsigned values to avoid breaking any application that may rely on 128 being a valid value. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Tested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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.