• Martin Fuzzey's avatar
    ARM: imx53: Set DDR pins to high impedance when in suspend to RAM. · 1579c7b9
    Martin Fuzzey authored
    In order to save power the DDR pins should be put into high
    impedance when in suspend to RAM.
    
    This requires manually requesting self refresh (rather than using the
    automatic mode implemented by the CCM / ESDCTL), followed by
    reconfiguring the IOMUXC.
    
    Of course the code to do this cannot itself run from DDR so the
    code is copied to and executed from internal memory.
    
    In my tests using a custom i.MX53 board with LPDDR2 RAM
    this reduced the suspend power consumption from 200mW to 60mW.
    Signed-off-by: default avatarMartin Fuzzey <mfuzzey@parkeon.com>
    Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
    1579c7b9
suspend-imx53.S 3.42 KB