738845b022
[ Upstream commit 3f42b142ea1171967e40e10e4b0241c0d6d28d41 ]
After upgrading from 5.16 to 6.1, our board with a MAX14830 started
producing lots of garbage data over UART. Bisection pointed out commit
285e76fc049c as the culprit. That patch tried to replace hand-written
code which I added in 2b4bac48c1084 ("serial: max310x: Use batched reads
when reasonably safe") with the generic regmap infrastructure for
batched operations.
Unfortunately, the `regmap_raw_read` and `regmap_raw_write` which were
used are actually functions which perform IO over *multiple* registers.
That's not what is needed for accessing these Tx/Rx FIFOs; the
appropriate functions are the `_noinc_` versions, not the `_raw_` ones.
Fix this regression by using `regmap_noinc_read()` and
`regmap_noinc_write()` along with the necessary `regmap_config` setup;
with this patch in place, our board communicates happily again. Since
our board uses SPI for talking to this chip, the I2C part is completely
untested.
Fixes: 285e76fc049c ("serial: max310x: use regmap methods for SPI batch operations")
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/r/79db8e82aadb0e174bc82b9996423c3503c8fb37.1680732084.git.jan.kundrat@cesnet.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.