• Michael van der Westhuizen's avatar
    spi: dw: Allow interface drivers to limit data I/O to word sizes · c4fe57f7
    Michael van der Westhuizen authored
    The commit dd114443 ("spi: dw-spi: Convert 16bit accesses to 32bit
    accesses") changed all 16bit accesses in the DW_apb_ssi driver to 32bit.
    This, unfortunately, breaks data register access on picoXcell, where the
    DW IP needs data register accesses to be word accesses (all other
    accesses appear to be OK).
    This change introduces a new master variable to allow interface drivers
    to specify that 16bit data transfer I/O is required.  This change also
    introduces the ability to set this variable via device tree bindings in
    the MMIO interface driver.  Both the core and the MMIO interface driver
    default to the current 32bit behaviour.
    Before this change, on a picoXcell pc3x3:
     spi_master spi32766: interrupt_transfer: fifo overrun/underrun
     m25p80 spi32766.0: error -5 reading 9f
     m25p80: probe of spi32766.0 failed with error -5
    After this change:
     m25p80 spi32766.0: m25p40 (512 Kbytes)
    Fixes: dd114443 ("spi: dw-spi: Convert 16bit accesses to 32bit accesses")
    Signed-off-by: default avatarMichael van der Westhuizen <michael@smart-africa.com>
    Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
spi-dw.h 5.96 KB