mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-01 04:53:09 -04:00
f287f971e2
Add 9th bit multipoint addressing mode for DW UART. 9th bit addressing can be used only when HW RS485 is available. Updating RAR (receive address register) is bit tricky because busy indication is not be available when DW UART is strictly 16550 compatible, which is the case with the hardware I was testing with. RAR should not be updated while receive is in progress which is now achieved by deasserting RE and waiting for one frame (in case rx would be in progress, the driver seems to have no way of knowing it w/o busy indication). Because of this complexity, it's better to avoid doing it unless really needed. Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Co-developed-by: Raymond Tan <raymond.tan@intel.com> Co-developed-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Raymond Tan <raymond.tan@intel.com> Signed-off-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220624204210.11112-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.