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    SubjectRe: [PATCH v2 4/4] da850-evm: add baseboard UI expander buttons, switches and LEDs
    Hi Sekhar,

    On Mon, Nov 22, 2010 at 7:00 AM, Nori, Sekhar <> wrote:
    > Thanks for the explanation. I should have probably asked
    > earlier, why do we need to prevent sysfs access of
    > deep sleep enable and sw reset pins? We don't seem to be
    > using them in the kernel either.

    You're welcome.

    I was assuming that those pins were not exported as gpio pins on
    purpose; I was taking the prudent approach to prevent haphazard
    toggling of sw_rst and deep_sleep_en from userspace. sw_rst because it
    could initiate a reset of the cpu when toggled and deep_sleep_en
    because it can override the behaviour of davinci_pm_enter().

    I'm not sure how they would be used by existing kernel classes either.
    The sw_rst pin could be used for reset but since it is on the other
    end of an i2c bus and there is an existing implementation of reset
    using the on chip watchdog I don't think it would be benficial to
    switch. Deep_sleep_en could override the behaviour in
    davinci_pm_enter() -- _maybe_ (I don't really know) it could be used
    as a hardware-assisted suspend-blocker? But I totally guessing here.

    Best Regards,
    Ben Gardiner

    Nanometrics Inc.

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