68a53d1212
[ Upstream commit 79d713baf63c8f23cc58b304c40be33d64a12aaf ] In some APIs we would like to assign the special value to iotype and compare against it in another places. Introduce UPIO_UNKNOWN for this purpose. Note, we can't use 0, because it's a valid value for IO port access. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240304123035.758700-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 87d80bfbd577 ("serial: 8250_dw: Don't use struct dw8250_data outside of 8250_dw") Signed-off-by: Sasha Levin <sashal@kernel.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.