ADC calibration is only required for a 80 MHz sampling rate (i.e. for 40 MHz channels), when the chip utilizes the pair of ADCs in interleved mode. Calibration on a 20 MHz channel will never be completed. Previous channel check is trying to exclude all channels where the calibration will get stuck. It effectively blocks the calibration run for HT20 channels, but fails to exclude 20 MHz channels without HT (e.g. legacy mode channels). Fix this issue by reworking the channel check to explicitly allow ADCs gain & DC offset calibrations for HT40 channels only. Also update the complicated comment to make it clear that these calibrations are for multi-ADC mode only. Stuck ADCs calibration blocks the NF calibration, what could make it impossible to work in a noisy evironment: too big Rx attentuation, invalid RSSI value, etc. So this change is actually more of a NF calibration fix rather then the ADC calibration fix. Run tested with AR9220. Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Link: https://lore.kernel.org/r/20200424004923.17129-2-ryazanov.s.a@gmail.com |
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| arch | ||
| block | ||
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| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
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| README | ||
README
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.