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Some platform based configuration setup of spi-imx SPI devices does not set the "chip_select" to the actual hardware chip select used. This works because the cs_gpio mapping that is associated with this platform setup maps the chip_select offset used to the appropriate hardware chip select. The spi-imx driver uses the chip_select as an index into the cs_gpio array and ultimately gets the correct hardware chip select for its hardware setup. The motivation is to be able to eventually modify the spi-imx code to use the "chip_select" directly for harwdare setup instead of indirectly via the cs_gpio mapping array. This change only affects platforms using the hardware chip select addressing method for their SPI devices (sometimes called native chip select). The majority of devices using the spi-imx driver use the GPIO addressing method. The change to use the correct "chip_select" is strait forward. But the cs_gpio mapping arrary also needs to be modifed to match that change. In simple terms the cs_gpio mapping should always have the hardware chip select number at its same index offset. There is no functional change with these patches. The three affected platforms should work exactly as before. However I don't have any of these platforms (or access to them) and so I can't test them. So this patch is compile tested only. Signed-off-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: Shawn Guo <shawnguo@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.