c4c81db5cf
LPUART IP has a bug that it treats the CTS as higher priority than the break signal, which cause the break signal sending through UARTCTRL_SBK may impacted by the CTS input if the HW flow control is enabled. Add this workaround patch to fix the IP bug, we can disable CTS before asserting SBK to avoid any interference from CTS, and re-enable it when break off. Such as for the bluetooth chip power save feature, host can let the BT chip get into sleep state by sending a UART break signal, and wake it up by turning off the UART break. If the BT chip enters the sleep mode successfully, it will pull up the CTS line, if the BT chip is woken up, it will pull down the CTS line. If without this workaround patch, the UART TX pin cannot send the break signal successfully as it affected by the BT CTS pin. After adding this patch, the BT power save feature can work well. Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Link: https://lore.kernel.org/r/20221214031137.28815-2-sherry.sun@nxp.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.