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bitfield.h defines FIELD_GET() and FIELD_PREP() macros to access bitfields using the mask alone, with no need for separate shift. Indeed, the shift is redundant. We define REG_FIELD_GET() and REG_FIELD_PREP() wrappers for the above, in part to force u32 and for consistency with REG_BIT() and REG_GENMASK(), but also as we'll need to redefine REG_FIELD_PREP() in follow-up work to make it produce integer constant expressions. For the most part, REG_FIELD_GET() is shorter than masking followed by shift, and arguably has more clarity. REG_FIELD_PREP() can get more verbose than simply shifting in place, but it does provide masking to ensure we don't overflow the mask, something we usually don't bother with currently. Convert power sequencer registers as an example. v3: - temp variable removal (Chris) - rebase v2: - Add the REG_FIELD_GET() and REG_FIELD_PREP() wrappers to use them consistently from the start. Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/ab68f52e55e3961bde9458c0d85a12d98ef471df.1552657998.git.jani.nikula@intel.com
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.