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The ROHM BD79104 is a 12-bit, 8-channel ADC with two power supply pins, connected to SPI. It's worth noting the IC requires SPI MODE 3, (CPHA = 1, CPOL = 1). I used an evaluation board "BD79104FV-EVK-001" from ROHM. With this board I had problems to have things working correctly with higher SPI clock frequencies. I didn't do thorough testing for maximum frequency though. First attempt was 40M, then 20M and finally 4M. With 20M it seemed as if the read values were shifted by 1 bit. With 4M it worked fine. The component data-sheet is not exact what comes to the maximum SPI frequency. It says SPI frequency is 20M - "unless othervice specified". Additionally, it says that maximum sampling rate is 1Mhz, and since reading a sample requires writing the channel (16 bits) and reading data (16 bits) - we get some upper limit from this. >From the "frequency is 20M, unless othervice specified" I picked the maximum frequency 20M - and did assumption that my problems with 20M weren't related to the BD79104 - but to the evaluation board "BD79104FV-EVK-001". Add bindings for the ROHM BD79104 ADC. Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://patch.msgid.link/2a4c65ee35cb79c6b29dbc59cfd9bc7d615a08ac.1744022065.git.mazziesaccount@gmail.com 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.