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    SubjectRe: [PATCH] ARM: SAMSUNG: Save/restore GPIO drive strength across suspend/resume
    On Sat, Nov 12, 2011 at 6:01 AM, Inderpal Singh
    <> wrote:

    > GPIO driver strength settings are not preserved across suspend/resume
    > for s5pc100, s5pv210 and Exynos platforms which has been the cause of
    > mmc/sd card read/write failures after resume. Fix this by saving and
    > restoring the GPIO driver strength register settings across suspend/resume.
    > Signed-off-by: Inderpal Singh <>

    On a related theme: I am thinking about how to support preserving
    drive strength (etc) across suspend/resume and deepsleep in the
    pincontrol subsystem.

    Currently I am playing with the idea to let pin groups have states,
    as the different configurations seem to be 90% or so about very
    specific sleep modes, so say:

    pinconf_set_group_state("mmcgroup", PINCONF_STATE_ACTIVE);
    pinconf_set_group_state("mmcgroup", PINCONF_STATE_SUSPENDED);
    pinconf_set_group_state("mmcgroup", PINCONF_STATE_SLEEP);

    This would then instruct each pin controller driver to configure
    each pin apropriately for the given state, and that cross-references
    to a table keeping track of the preset per-pin for each state.

    My intuitive idea is that letting the core keep track of the state of
    every pin and letting pin groups harness the settings for a group
    of pins is the proper approach to the problem.

    Do you think something like this will work for the S5P:s?

    Linus Walleij

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