ARM: imx53: Set DDR pins to high impedance when in suspend to RAM.
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:Martin Fuzzey <mfuzzey@parkeon.com> Signed-off-by:
Shawn Guo <shawn.guo@linaro.org>
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5739b919
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