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1cfb22c277
Add a check to ad7173_update_scan_mode() to ensure that we didn't exceed the maximum number of unique channel configurations. In the AD7173 family of chips, there are some chips that have 16 CHANNELx registers but only 8 setups (combination of CONFIGx, FILTERx, GAINx and OFFSETx registers). Since commit92c2472169("iio: adc: ad7173: fix num_slots"), it is possible to have more than 8 channels enabled in a scan at the same time, so it is possible to get a bad configuration when more than 8 channels are using unique configurations. This happens because the algorithm to allocate the setup slots only takes into account which slot has been least recently used and doesn't know about the maximum number of slots available. Since the algorithm to allocate the setup slots is quite complex, it is simpler to check after the fact if the current state is valid or not. So this patch adds a check in ad7173_update_scan_mode() after setting up all of the configurations to make sure that the actual setup still matches the requested setup for each enabled channel. If not, we prevent the scan from being enabled and return an error. The setup comparison in ad7173_setup_equal() is refactored to a separate function since we need to call it in two places now. Fixes:92c2472169("iio: adc: ad7173: fix num_slots") Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://patch.msgid.link/20250722-iio-adc-ad7173-fix-setup-use-limits-v2-1-8e96bdb72a9c@baylibre.com Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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 reStructuredText 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.