[libcamera-devel] [PATCH v3 03/14] libcamera: v4l2_device: Add method to retrieve all supported controls
Jacopo Mondi
jacopo at jmondi.org
Mon Jul 1 18:12:53 CEST 2019
Hi Laurent,
On Mon, Jul 01, 2019 at 07:05:04PM +0300, Laurent Pinchart wrote:
> Hi Jacopo,
>
> On Mon, Jul 01, 2019 at 05:05:44PM +0200, Jacopo Mondi wrote:
> > On Mon, Jul 01, 2019 at 02:38:06AM +0300, Laurent Pinchart wrote:
> > > Add a new controls() method to the V4L2Device class to retrieve the map
> > > of all supported controls. This is needed in order to dynamically query
> > > the supported controls, for instance for drivers that support different
> > > sets of controls depending on the device model.
> > >
> > > To make the API easier to use, create a type alias for the control ID to
> > > ControlInfo and use it.
> > >
> > > Remove the getControlInfo() method that is not used externally, as it
> > > can now be replaced by accessing the full list of controls.
> > >
> > > Update the CameraSensor API accordingly.
> > >
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > > ---
> > > src/libcamera/camera_sensor.cpp | 10 ++++------
> > > src/libcamera/include/camera_sensor.h | 5 ++---
> > > src/libcamera/include/v4l2_controls.h | 6 ++++--
> > > src/libcamera/include/v4l2_device.h | 9 ++++-----
> > > src/libcamera/v4l2_controls.cpp | 5 +++++
> > > src/libcamera/v4l2_device.cpp | 25 +++++++++----------------
> > > 6 files changed, 28 insertions(+), 32 deletions(-)
> > >
> > > diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> > > index 471c3e2e6e47..14f631e8ecf7 100644
> > > --- a/src/libcamera/camera_sensor.cpp
> > > +++ b/src/libcamera/camera_sensor.cpp
> > > @@ -248,14 +248,12 @@ int CameraSensor::setFormat(V4L2SubdeviceFormat *format)
> > > }
> > >
> > > /**
> > > - * \brief Retrieve information about a control
> > > - * \param[in] id The control ID
> > > - * \return A pointer to the V4L2ControlInfo for control \a id, or nullptr
> > > - * if the sensor doesn't have such a control
> > > + * \brief Retrieve the supported V4L2 controls
> > > + * \return A map of the V4L2 controls supported by the sensor
> > > */
> > > -const V4L2ControlInfo *CameraSensor::getControlInfo(unsigned int id) const
> > > +const V4L2ControlInfoMap &CameraSensor::controls() const
> > > {
> > > - return subdev_->getControlInfo(id);
> > > + return subdev_->controls();
> > > }
> > >
> > > /**
> > > diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
> > > index b42e7b8e1343..fe033fb374c1 100644
> > > --- a/src/libcamera/include/camera_sensor.h
> > > +++ b/src/libcamera/include/camera_sensor.h
> > > @@ -13,12 +13,11 @@
> > > #include <libcamera/geometry.h>
> > >
> > > #include "log.h"
> > > +#include "v4l2_controls.h"
> > >
> > > namespace libcamera {
> > >
> > > class MediaEntity;
> > > -class V4L2ControlInfo;
> > > -class V4L2ControlList;
> > > class V4L2Subdevice;
> > >
> > > struct V4L2SubdeviceFormat;
> > > @@ -43,7 +42,7 @@ public:
> > > const Size &size) const;
> > > int setFormat(V4L2SubdeviceFormat *format);
> > >
> > > - const V4L2ControlInfo *getControlInfo(unsigned int id) const;
> > > + const V4L2ControlInfoMap &controls() const;
> > > int getControls(V4L2ControlList *ctrls);
> > > int setControls(V4L2ControlList *ctrls);
> > >
> > > diff --git a/src/libcamera/include/v4l2_controls.h b/src/libcamera/include/v4l2_controls.h
> > > index 0047efab11fa..10b726504951 100644
> > > --- a/src/libcamera/include/v4l2_controls.h
> > > +++ b/src/libcamera/include/v4l2_controls.h
> > > @@ -8,11 +8,11 @@
> > > #ifndef __LIBCAMERA_V4L2_CONTROLS_H__
> > > #define __LIBCAMERA_V4L2_CONTROLS_H__
> > >
> > > +#include <map>
> > > +#include <stdint.h>
> >
> > Nit: C and C++ includes mixed?
>
> I wondered about that, as it seemed to me it was the general rules in
> libcamera, and the fact that they were separated here made me hesitate.
> I checked through the code base, and we generally mix them.
>
> I also thought we had documented this in the coding style, but it seems
> we haven't. I then remembered it was documented in
> https://google.github.io/styleguide/cppguide.html#Names_and_Order_of_Includes.
I see. I've been doing it wrong then
>
> > > #include <string>
> > > #include <vector>
> > >
> > > -#include <stdint.h>
> > > -
> > > #include <linux/v4l2-controls.h>
> > > #include <linux/videodev2.h>
> > >
> > > @@ -41,6 +41,8 @@ private:
> > > int64_t max_;
> > > };
> > >
> > > +using V4L2ControlInfoMap = std::map<unsigned int, V4L2ControlInfo>;
> > > +
> > > class V4L2Control
> > > {
> > > public:
> > > diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> > > index 24a0134a2cba..e7e9829cb05f 100644
> > > --- a/src/libcamera/include/v4l2_device.h
> > > +++ b/src/libcamera/include/v4l2_device.h
> > > @@ -13,19 +13,18 @@
> > > #include <linux/videodev2.h>
> > >
> > > #include "log.h"
> > > +#include "v4l2_controls.h"
> > >
> > > namespace libcamera {
> > >
> > > -class V4L2ControlInfo;
> > > -class V4L2ControlList;
> > > -
> > > class V4L2Device : protected Loggable
> > > {
> > > public:
> > > void close();
> > > bool isOpen() const { return fd_ != -1; }
> > >
> > > - const V4L2ControlInfo *getControlInfo(unsigned int id) const;
> > > + const V4L2ControlInfoMap &controls() const { return controls_; }
> > > +
> > > int getControls(V4L2ControlList *ctrls);
> > > int setControls(V4L2ControlList *ctrls);
> > >
> > > @@ -48,7 +47,7 @@ private:
> > > const struct v4l2_ext_control *v4l2Ctrls,
> > > unsigned int count);
> > >
> > > - std::map<unsigned int, V4L2ControlInfo> controls_;
> > > + V4L2ControlInfoMap controls_;
> > > std::string deviceNode_;
> > > int fd_;
> > > };
> > > diff --git a/src/libcamera/v4l2_controls.cpp b/src/libcamera/v4l2_controls.cpp
> > > index af017bce48ba..84258d9954d0 100644
> > > --- a/src/libcamera/v4l2_controls.cpp
> > > +++ b/src/libcamera/v4l2_controls.cpp
> > > @@ -114,6 +114,11 @@ V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
> > > * \return The V4L2 control maximum value
> > > */
> > >
> > > +/**
> > > + * \typedef V4L2ControlInfoMap
> > > + * \brief A map of control ID to V4L2ControlInfo
> >
> > Nit: shouldn't these be plurals?
>
> I think both work ("this container maps a control ID to a
> V4L2ControlInfo" or "this containter maps control IDs to V4L2ControlInfo
> instances"). I went for the former to avoid adding "instances". Now that
> I'm re-reading the code I will also replace control ID with ControlId.
>
No worries, was a very minor comment.
> > > + */
> > > +
> > > /**
> > > * \class V4L2Control
> > > * \brief A V4L2 control value
> > > diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> > > index 06939dead705..59fc98cefd4e 100644
> > > --- a/src/libcamera/v4l2_device.cpp
> > > +++ b/src/libcamera/v4l2_device.cpp
> > > @@ -111,19 +111,10 @@ void V4L2Device::close()
> > > */
> > >
> > > /**
> > > - * \brief Retrieve information about a control
> > > - * \param[in] id The control ID
> > > - * \return A pointer to the V4L2ControlInfo for control \a id, or nullptr
> > > - * if the device doesn't have such a control
> > > + * \fn V4L2Device::controls()
> > > + * \brief Retrieve the supported V4L2 controls
> >
> > " and the associated control information" ?
>
> I'm not sure that's needed, but I'll add it :-) How about "and their
> information" to make it shorter ?
i
this was very minor as well. As you wish.
>
> > > + * \return A map of the V4L2 controls supported by the device
> > > */
> > > -const V4L2ControlInfo *V4L2Device::getControlInfo(unsigned int id) const
> > > -{
> > > - auto it = controls_.find(id);
> > > - if (it == controls_.end())
> > > - return nullptr;
> > > -
> > > - return &it->second;
> > > -}
> > >
> > > /**
> > > * \brief Read controls from the device
> > > @@ -158,13 +149,14 @@ int V4L2Device::getControls(V4L2ControlList *ctrls)
> > >
> > > for (unsigned int i = 0; i < count; ++i) {
> > > const V4L2Control *ctrl = ctrls->getByIndex(i);
> > > - const V4L2ControlInfo *info = getControlInfo(ctrl->id());
> > > - if (!info) {
> > > + const auto iter = controls_.find(ctrl->id());
> > > + if (iter == controls_.end()) {
> > > LOG(V4L2, Error)
> > > << "Control '" << ctrl->id() << "' not found";
> > > return -EINVAL;
> > > }
> > >
> > > + const V4L2ControlInfo *info = &iter->second;
> > > controlInfo[i] = info;
> > > v4l2Ctrls[i].id = info->id();
> > > }
> > > @@ -232,13 +224,14 @@ int V4L2Device::setControls(V4L2ControlList *ctrls)
> > >
> > > for (unsigned int i = 0; i < count; ++i) {
> > > const V4L2Control *ctrl = ctrls->getByIndex(i);
> > > - const V4L2ControlInfo *info = getControlInfo(ctrl->id());
> > > - if (!info) {
> > > + const auto iter = controls_.find(ctrl->id());
> > > + if (iter == controls_.end()) {
> > > LOG(V4L2, Error)
> > > << "Control '" << ctrl->id() << "' not found";
> > > return -EINVAL;
> > > }
> > >
> > > + const V4L2ControlInfo *info = &iter->second;
> >
> > An operation wrapping the explicit lookup was probably shorter to
> > write and read, but the change is good.
>
> Kieran made the same comment, and I agree. If the slightly longer error
> check is only needed here I think it's fine. If we end up finding that a
> pointer-or-nullptr version would be useful in more places, then I would
> like to look into how we could provide a utility to extend containers
> instead of having to add custom functions every time. e.g.
>
> const V4L2ControlInfo *info = utils::find(video_.controls(), ctrl->id());
I would then prefer what we have here :)
>
> That would still be slightly longer to write than
>
> const V4L2ControlInfo *info = video_.getControlInfo(ctrl->id());
>
> but in my opinion reasonably so, while providing the convenience helper
> for all our containers, without needing to explicitly provide a separate
> method each time.
No worries, we're talking about details. What you have here is fine!
Thanks
j
>
> > Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> >
> > > controlInfo[i] = info;
> > > v4l2Ctrls[i].id = info->id();
> > >
>
> --
> Regards,
>
> Laurent Pinchart
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