b8ba4d74f9
[ Upstream commit 683f65ded66a9a7ff01ed7280804d2132ebfdf7e ] In some circumstances on Intel LPSS controllers, toggling the LPSS CS control register doesn't actually cause the CS line to toggle. This seems to be failure of dynamic clock gating that occurs after going through a suspend/resume transition, where the controller is sent through a reset transition. This ruins SPI transactions that either rely on delay_usecs, or toggle the CS line without sending data. Whenever CS is toggled, momentarily set the clock gating register to "Force On" to poke the controller into acting on CS. Signed-off-by: Rajat Jain <rajatja@google.com> Signed-off-by: Evan Green <evgreen@chromium.org> Link: https://lore.kernel.org/r/20200211223700.110252-1-rajatja@google.com Signed-off-by: Mark Brown <broonie@kernel.org> 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.