Re: [PATCH] i2c: omap: fix spurious IRQs: disable/enable IRQ at INTC when idle

[Kalle Jokiniemi <kalle.jokiniemi@jollamobile.com>]

Hi,

la, 2012-10-13 kello 01:00 +0530, Shubhrajyoti Datta kirjoitti:
> On Sat, Oct 13, 2012 at 12:10 AM, Kevin Hilman
> <khilman@deeprootsystems.com> wrote:
> > From: Kevin Hilman <khilman@ti.com>
> >
> > 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

It is actually in middle of resume_noirq.

> > 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.

Does not work for me :(

As I said, the issue occurs for me when I enter static suspend (echo mem
> /sys/power/autosleep or /sys/power/state). I don't think doing this
just in runtime pm will fix my issue. Or do those handlers get run in
the normal suspend path as well?

- Kalle

> 
> >
> > Cc: Kalle Jokiniemi <kalle.jokiniemi@jollamobile.com>
> > Cc: Grygorii Strashko <grygorii.strashko@ti.com>
> > Cc: Shubhrajyoti Datta <shubhrajyoti@ti.com>,
> > Cc: Huzefa Kankroliwala <huzefank@ti.com>
> > Cc: Nishanth Menon <nm@ti.com>
> > Signed-off-by: Kevin Hilman <khilman@ti.com>
> > ---
> >  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
> >
> > --
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