On Thu, Sep 13, 2012 at 1:45 PM, Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> wrote: > From: Kevin Hilman <khilman@xxxxxx> > > On some platforms, bootloaders are known to do some interesting RTC > programming. Without going into the obscurities as to why this may be > the case, suffice it to say the the driver should not make any > assumptions about the state of the RTC when the driver loads. In > particular, the driver probe should be sure that all interrupts are > disabled until otherwise programmed. > > This was discovered when finding bursty I2C traffic every second on > Overo platforms. This I2C overhead was keeping the SoC from hitting > deep power states. The cause was found to be the RTC firing every > second on the I2C-connected TWL PMIC. > > Special thanks to Felipe Balbi for suggesting to look for a rogue > driver as the source of the I2C traffic rather than the I2C driver > itself. > > Special thanks to Steve Sakoman for helping track down the source of > the continuous RTC interrups on the Overo boards. > > Cc: Felipe Balbi <balbi@xxxxxx> > Cc: Steve Sakoman <steve@xxxxxxxxxxx> > Signed-off-by: Kevin Hilman <khilman@xxxxxx> Tested on Overo/Tobi, and I no longer see the 1/second interrupts. Also verified that alarm interrupts still work using rtcwake. Tested-by: Steve Sakoman <steve@xxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
