f24cb5a042
[ Upstream commit 5578d0a79b6430fa1543640dd6f2d397d0886ce7 ] There seems to be a bug within the mv64xxx I2C controller, wherein the status register may not necessarily contain valid value immediately after the IFLG flag is set in the control register. My theory is that the controller: - first sets the IFLG in control register - then updates the status register - then raises an interrupt This may sometime cause weird bugs when in atomic mode, since in this mode we do not wait for an interrupt, but instead we poll the control register for IFLG and read status register immediately after. I encountered -ENXIO from mv64xxx_i2c_fsm() due to this issue when using this driver in atomic mode. Note that I've only seen this issue on Armada 385, I don't know whether other SOCs with this controller are also affected. Also note that this fix has been in U-Boot for over 4 years [1] without anybody complaining, so it should not cause regressions. [1] https://source.denx.de/u-boot/u-boot/-/commit/d50e29662f78 Fixes: 544a8d75f3d6 ("i2c: mv64xxx: Add atomic_xfer method to driver") Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Wolfram Sang <wsa@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.