[libcamera-devel] [RFC v1 2/5] libcamera: camera_lens: Get maximum VCM steps

[Kate Hsuan]

Hi Jacopo,

On Thu, Apr 14, 2022 at 4:22 PM Jacopo Mondi <jacopo at jmondi.org> wrote:
>
> Hi Kate,
>
> On Thu, Apr 14, 2022 at 03:43:39PM +0800, Kate Hsuan via libcamera-devel wrote:
> > It allows other components to get the maximum VCM steps. It first creates
> > a control list and set V4L2_CID_FOCUS_ABSOLUTE control to it. Then, it
> > calls a lower layer call, getAttributes() to get the maximum VCM steps
> > from the kernel.
>
> I might have missed something here.
>
> V4L2Device::controls() returns you a ControlInfoMap for all the
> controls registered on the lens subdevice, with the controls' min, max
> and default values collected at subdev open time with
> V4L2Device::listControls()
>
> Is there a reason I have missed about why you need to re-fetch the
> control's limits again ?
>

Ah. I might miss this V4L2Device::listControls(). I could try this in
my v2 patch.

Thank you.

> If you need to collect the V4L2_CID_FOCUS_ABSOLUTE control maximum
> value I think you could very well do so at validateLensDriver() time.
>
> Thanks
>    j
>
> >
> > Signed-off-by: Kate Hsuan<hpa at redhat.com>
> > ---
> >  include/libcamera/internal/camera_lens.h |  1 +
> >  src/libcamera/camera_lens.cpp            | 18 ++++++++++++++++++
> >  2 files changed, 19 insertions(+)
> >
> > diff --git a/include/libcamera/internal/camera_lens.h b/include/libcamera/internal/camera_lens.h
> > index 277417da..48761d68 100644
> > --- a/include/libcamera/internal/camera_lens.h
> > +++ b/include/libcamera/internal/camera_lens.h
> > @@ -27,6 +27,7 @@ public:
> >
> >       int init();
> >       int setFocusPosition(int32_t position);
> > +     int getFocusCapabilityies();
> >
> >       const std::string &model() const { return model_; }
> >
> > diff --git a/src/libcamera/camera_lens.cpp b/src/libcamera/camera_lens.cpp
> > index b3d48199..5d00652d 100644
> > --- a/src/libcamera/camera_lens.cpp
> > +++ b/src/libcamera/camera_lens.cpp
> > @@ -73,6 +73,10 @@ int CameraLens::init()
> >               return ret;
> >
> >       model_ = subdev_->model();
> > +
> > +     ControlList lensCtrls(subdev_->controls());
> > +     subdev_->getAttributes(&lensCtrls);
> > +
> >       return 0;
> >  }
> >
> > @@ -95,6 +99,20 @@ int CameraLens::setFocusPosition(int32_t position)
> >       return 0;
> >  }
> >
> > +int CameraLens::getFocusCapabilityies()
> > +{
> > +     ControlValue retVal;
> > +     ControlList lensCtrls(subdev_->controls());
> > +     int32_t ret = 2023;
> > +
> > +     lensCtrls.set(V4L2_CID_FOCUS_ABSOLUTE, static_cast<int32_t>(ret));
> > +     subdev_->getAttributes(&lensCtrls);
> > +     retVal = lensCtrls.get(V4L2_CID_FOCUS_ABSOLUTE);
> > +     ret = retVal.get<int32_t>();
> > +
> > +     return ret;
> > +}
> > +
> >  int CameraLens::validateLensDriver()
> >  {
> >       int ret = 0;
> > --
> > 2.35.1
> >
>


-- 
BR,
Kate