• Steven King's avatar
    spi: Add Freescale/Motorola Coldfire QSPI driver · 34b8c661
    Steven King authored
    Add support for the QSPI controller found some on Freescale/Motorola
    Coldfire MCUs.
    
    Full duplex, active high cs, spi modes 0-3 and word sizes 8-16 bits are
    supported.  The hardware drives the MISO, MOSI and SCLK lines, but the chip
    selects are managed via GPIO and must be configured by the board code.
    
    The QSPI controller has an 80 byte buffer which allows us to transfer up to 16
    words at a time.  For transfers longer than 16 words, we split the buffer in
    half so we can update in one half while the controller is operating on the
    other half.  Interrupt latencies then ultimately limits our sustained thru-put
    to something less than half the maximum speed supported by the part.
    Signed-off-by: default avatarSteven King <sfking@fdwdc.com>
    Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
    34b8c661
Makefile 2.17 KB