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The spi_master.setup() callback must not change configuration registers, as that could corrupt I/O that is in progress for other SPI slaves. The only exception is the configuration of the native chip select polarity in SPI master mode, as a wrong chip select polarity will cause havoc during all future transfers to any other SPI slave. Hence stop writing to registers in sh_msiof_spi_setup(), unless it is the first call for a controller using a native chip select, or unless native chip select polarity has changed (note that you'll loose anyway if I/O is in progress). Even then, only do what is strictly necessary, instead of calling sh_msiof_spi_set_pin_regs(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.