On Sat, Oct 13, 2012 at 12:10 AM, Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> wrote: > From: Kevin Hilman <khilman@xxxxxx> > > Currently, runtime PM is used to keep the device enabled only during > active transfers and for a configurable runtime PM autosuspend timout > after an xfer. > > In addition to idling the device, driver's ->runtime_suspend() method > currently disables device interrupts when idle. However, on some SoCs > (notably OMAP4+), the I2C hardware may shared with other coprocessors. > This means that the MPU will still recieve interrupts if a coprocessor > is using the I2C device. To avoid this, also disable interrupts at > the MPU INTC when idling the device in ->runtime_suspend() (and > re-enable them in ->runtime_resume().) This part based on an original > patch from Shubhrajyoti Datta. NOTE: for proper sharing the I2C with > a coprocessor, this driver still needs hwspinlock support added. > > This change is also meant to address an issue reported by Kalle > Jokiniemi where I2C bus interrupt may be enabled before an I2C device > interrupt handler (e.g. just after noirq resume phase) causing an > interrupt flood on the I2C bus interrupt before the device interrupt > is enabled (e.g. interrupts coming from devices on I2C connected PMIC > before the PMIC chained hanlder is enabled.) This problem is addresed > by ensuring that the I2C bus interrupt left disabled until an I2C xfer > is requested. Looks good to me. Will wait for Kalle though. > > Cc: Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxxxxxxxx> > Cc: Grygorii Strashko <grygorii.strashko@xxxxxx> > Cc: Shubhrajyoti Datta <shubhrajyoti@xxxxxx>, > Cc: Huzefa Kankroliwala <huzefank@xxxxxx> > Cc: Nishanth Menon <nm@xxxxxx> > Signed-off-by: Kevin Hilman <khilman@xxxxxx> > --- > drivers/i2c/busses/i2c-omap.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index db31eae..e6413e8 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1255,6 +1255,7 @@ static int omap_i2c_runtime_suspend(struct device *dev) > /* Flush posted write */ > omap_i2c_read_reg(_dev, OMAP_I2C_STAT_REG); > } > + disable_irq(_dev->irq); > > return 0; > } > @@ -1275,6 +1276,8 @@ static int omap_i2c_runtime_resume(struct device *dev) > omap_i2c_write_reg(_dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); > } > > + enable_irq(_dev->irq); > + > /* > * Don't write to this register if the IE state is 0 as it can > * cause deadlock. > -- > 1.7.9.2 > > -- > 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 -- 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
