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53ca18acbe
The spi_imx->spi_bus_clk may be uninitialized and thus also zero in
mx51_ecspi_prepare_message(), which would lead to division by zero
in kernel. Since bitbang .setup_transfer callback which initializes
the spi_imx->spi_bus_clk is called after bitbang prepare_message
callback, iterate over all the transfers in spi_message, find the
one with lowest bus frequency, and use that bus frequency for the
delay calculation.
Note that it is not possible to move this CONFIGREG delay back into
the .setup_transfer callback, because that is invoked too late, after
the GPIO chipselects were already configured.
Fixes: 135cbd378e ("spi: imx: mx51-ecspi: Reinstate low-speed CONFIGREG delay")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210726100102.5188-1-marex@denx.de
Signed-off-by: Mark Brown <broonie@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.