Re: [PATCH v3 3/5] media: atmel-isc: Enable the clocks during probe

[Yang, Wenyou]

Hi Sakari,

On 2017/10/9 15:58, Sakari Ailus wrote:
> Hi
> Wenyou,
>
> On Mon, Oct 09, 2017 at 01:49:44PM +0800, Yang, Wenyou wrote:
> > Hi Sakari,
> >
> > Sorry for late answer, because I was in vacation last week.
> >
> > On 2017/9/29 5:25, Sakari Ailus wrote:
> > > Hi Wenyou,
> > >
> > > On Thu, Sep 28, 2017 at 04:18:26PM +0800, Wenyou Yang wrote:
> > > > To meet the relationship, enable the HCLOCK and ispck during the
> > > > device probe, "isc_pck frequency is less than or equal to isc_ispck,
> > > > and isc_ispck is greater than or equal to HCLOCK."
> > > > Meanwhile, call the pm_runtime_enable() in the right place.
> > > >
> > > > Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxxxxxx>
> > > > ---
> > > >
> > > > Changes in v3: None
> > > > Changes in v2: None
> > > >
> > > >    drivers/media/platform/atmel/atmel-isc.c | 31 +++++++++++++++++++++++++------
> > > >    1 file changed, 25 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c
> > > > index 0b15dc1a3a0b..f092c95587c1 100644
> > > > --- a/drivers/media/platform/atmel/atmel-isc.c
> > > > +++ b/drivers/media/platform/atmel/atmel-isc.c
> > > > @@ -1594,6 +1594,7 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
> > > >    	struct isc_subdev_entity *sd_entity;
> > > >    	struct video_device *vdev = &isc->video_dev;
> > > >    	struct vb2_queue *q = &isc->vb2_vidq;
> > > > +	struct device *dev = isc->dev;
> > > >    	int ret;
> > > >    	ret = v4l2_device_register_subdev_nodes(&isc->v4l2_dev);
> > > > @@ -1677,6 +1678,10 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
> > > >    		return ret;
> > > >    	}
> > > > +	pm_runtime_set_active(dev);
> > > > +	pm_runtime_enable(dev);
> > > > +	pm_request_idle(dev);
> > > Remember that the driver's async complete function could never get called.
> > >
> > > What would be the reason to move it here?
> > The ISC provides the clock for the sensor, namely, it is the clock provider
> > for the external sensor.
> > So it keeps active to make the sensor probe successfully.
> > Otherwise, the sensor, such as 0v7670 fails to probe due to the failure to
> > clk_enable().
> You'll still need to balance the get and put calls.
>
> complete callback is not necessarily called at all or could be called
> multiple times. Instead, you should probably do pm_runtime_get_sync() when
> the clock is enabled and put when it's disabled.
I will send v4 to update it.

Thank you for your advice.

Best Regards,
Wenyou Yang