On Wed, Dec 03, 2014 at 06:01:25PM +0200, Mika Westerberg wrote:
> On Mon, Dec 01, 2014 at 04:09:32PM -0800, David E. Box wrote:
> > Adds support for acquiring and releasing a hardware bus lock in the i2c
> > designware core transfer function. This is needed for i2c bus controllers
> > that are shared with but not controlled by the kernel.
> >
> > Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-designware-core.c | 11 +++++++++++
> > drivers/i2c/busses/i2c-designware-core.h | 6 ++++++
> > drivers/i2c/busses/i2c-designware-platdrv.c | 18 +++++++++++++-----
> > 3 files changed, 30 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> > index 3c20e4b..377deeb 100644
> > --- a/drivers/i2c/busses/i2c-designware-core.c
> > +++ b/drivers/i2c/busses/i2c-designware-core.c
> > @@ -631,6 +631,14 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> > dev->abort_source = 0;
> > dev->rx_outstanding = 0;
> >
> > + if (dev->acquire_lock) {
> > + ret = dev->acquire_lock(dev);
> > + if (ret) {
> > + dev_err(dev->dev, "couldn't acquire bus ownership\n");
> > + goto done;
>
> I wonder what happens now since you failed to acquire the lock...
>
> > + }
> > + }
> > +
> > ret = i2c_dw_wait_bus_not_busy(dev);
> > if (ret < 0)
> > goto done;
> > @@ -676,6 +684,9 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> > ret = -EIO;
> >
> > done:
> > + if (dev->release_lock)
> > + dev->release_lock(dev);
>
> ... but here you unconditionally release it?
>
Releasing the lock unconditionally isn't a problem, but it is an unnecessary
path should we fail to acquire the lock. I'll add another label to skip it.
Dave
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