Hi Kevin, > -----Original Message----- > From: Kevin Hilman [mailto:khilman@xxxxxx] > Sent: Friday, January 28, 2011 5:49 AM > To: Ben Dooks; Rajendra Nayak; linux-i2c@xxxxxxxxxxxxxxx > Cc: linux-omap@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: [PATCH] i2c: OMAP: fix static suspend vs. runtime suspend > > When runtime PM is enabled, each OMAP i2c device is suspended after > each i2c xfer. However, there are two cases when the static suspend > methods must be used to ensure the devices are suspended: > > 1) runtime PM is disabled, either at compile time or dynamically > via /sys/devices/.../power/control. > 2) an i2c client driver uses i2c during it's suspend callback, thus > leaving the i2c driver active (NOTE: runtime suspend transitions are > disabled during system suspend, so i2c activity during system > suspend will runtime resume the device, but not runtime (re)suspend it.) > > Since the actual work to suspend the device is handled by the > subsytem, call the bus methods to take care of it. The patch looks good to me. Thanks for the fix. Validated suspend on OMAP4sdp with the patch. Can you elaborate a bit more on how/why runtime PM transitions are disabled during system suspend, and how is it taken care of that a runtime resume of a device works however a subsequent runtime (re)suspend does not? Regards, Rajendra > > NOTE: This takes care of a known suspend problem on OMAP3 where the > TWL RTC driver does i2c xfers during its suspend path leaving the i2c > driver in an active state (since runtime suspend transistions are > disabled.) > > Signed-off-by: Kevin Hilman <khilman@xxxxxx> > --- > Ben, this is a regression in 2.6.38 so hopefully this can be queued > in the 2.6.38-rc cycle. Thanks. > > drivers/i2c/busses/i2c-omap.c | 28 ++++++++++++++++++++++++++++ > 1 files changed, 28 insertions(+), 0 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index b605ff3..0541df9 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1137,12 +1137,40 @@ omap_i2c_remove(struct platform_device *pdev) > return 0; > } > > +#ifdef CONFIG_SUSPEND > +static int omap_i2c_suspend(struct device *dev) > +{ > + if (!pm_runtime_suspended(dev)) > + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) > + dev->bus->pm->runtime_suspend(dev); > + > + return 0; > +} > + > +static int omap_i2c_resume(struct device *dev) > +{ > + if (!pm_runtime_suspended(dev)) > + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) > + dev->bus->pm->runtime_resume(dev); > + > + return 0; > +} > + > +static struct dev_pm_ops omap_i2c_pm_ops = { > + .suspend = omap_i2c_suspend, > + .resume = omap_i2c_resume, > +}; > +#else > +#define omap_i2c_pm_ops NULL > +#endif > + > static struct platform_driver omap_i2c_driver = { > .probe = omap_i2c_probe, > .remove = omap_i2c_remove, > .driver = { > .name = "omap_i2c", > .owner = THIS_MODULE, > + .pm = &omap_i2c_pm_ops, > }, > }; > > -- > 1.7.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
