• Greg Ungerer's avatar
    ARM: imx: set correct chip_select in platform setup · 901f26bc
    Greg Ungerer authored
    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: default avatarGreg Ungerer <gerg@linux-m68k.org>
    Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
    901f26bc
mach-mx31moboard.c 16.2 KB