[PATCH v3] v4l2: Support setting frame rate in the V4L2 Adaptation layer

[Kieran Bingham]

Hi All? (me included as I see my SoB here)

Quoting Nejc Galof (2022-02-25 14:45:07)
> The V4L2 adaptation layer can already support streaming with components
> such as OpenCV, however it is not accepting, or handling any requests to
> configure the frame rate.
> 
> In V4L2 the frame rate is set by configuring the timeperframe component
> of the v4l2_streamparm structure through the VIDIOC_S_PARM ioctl.
> 
> Extend the V4L2 compatibility layer to accept the VIDIOC_S_PARM ioctls
> and provide an interface for setting controls on the V4L2Camera class to
> set the requested rate when starting the camera.
> 

This patch looks sane, but seems to have slipped through the net.

It needs to be rebased due to a merge conflict on headers being moved
though, which I've just done so I'll send that as v4 with my RB tag from
here:

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> Signed-off-by: Nejc Galof <galof.nejc at gmail.com>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/v4l2/v4l2_camera.cpp       | 12 +++++++++---
>  src/v4l2/v4l2_camera.h         |  5 +++++
>  src/v4l2/v4l2_camera_proxy.cpp | 24 ++++++++++++++++++++++++
>  src/v4l2/v4l2_camera_proxy.h   |  1 +
>  4 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp
> index e922b9e6..e4eb3a2b 100644
> --- a/src/v4l2/v4l2_camera.cpp
> +++ b/src/v4l2/v4l2_camera.cpp
> @@ -12,13 +12,15 @@
>  
>  #include <libcamera/base/log.h>
>  
> +#include <libcamera/control_ids.h>
> +
>  using namespace libcamera;
>  
>  LOG_DECLARE_CATEGORY(V4L2Compat)
>  
>  V4L2Camera::V4L2Camera(std::shared_ptr<Camera> camera)
> -       : camera_(camera), isRunning_(false), bufferAllocator_(nullptr),
> -         efd_(-1), bufferAvailableCount_(0)
> +       : camera_(camera), controls_(controls::controls), isRunning_(false),
> +         bufferAllocator_(nullptr), efd_(-1), bufferAvailableCount_(0)
>  {
>         camera_->requestCompleted.connect(this, &V4L2Camera::requestComplete);
>  }
> @@ -203,10 +205,12 @@ int V4L2Camera::streamOn()
>         if (isRunning_)
>                 return 0;
>  
> -       int ret = camera_->start();
> +       int ret = camera_->start(&controls_);
>         if (ret < 0)
>                 return ret == -EACCES ? -EBUSY : ret;
>  
> +       controls_.clear();
> +
>         isRunning_ = true;
>  
>         for (Request *req : pendingRequests_) {
> @@ -266,6 +270,8 @@ int V4L2Camera::qbuf(unsigned int index)
>                 return 0;
>         }
>  
> +       request->controls().merge(std::move(controls_));
> +
>         ret = camera_->queueRequest(request);
>         if (ret < 0) {
>                 LOG(V4L2Compat, Error) << "Can't queue request";
> diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h
> index 03e74118..4c203e31 100644
> --- a/src/v4l2/v4l2_camera.h
> +++ b/src/v4l2/v4l2_camera.h
> @@ -15,6 +15,7 @@
>  #include <libcamera/base/shared_fd.h>
>  
>  #include <libcamera/camera.h>
> +#include <libcamera/controls.h>
>  #include <libcamera/framebuffer.h>
>  #include <libcamera/framebuffer_allocator.h>
>  
> @@ -49,6 +50,8 @@ public:
>                                   const libcamera::Size &size,
>                                   libcamera::StreamConfiguration *streamConfigOut);
>  
> +       libcamera::ControlList &controls() { return controls_; }
> +
>         int allocBuffers(unsigned int count);
>         void freeBuffers();
>         int getBufferFd(unsigned int index);
> @@ -69,6 +72,8 @@ private:
>         std::shared_ptr<libcamera::Camera> camera_;
>         std::unique_ptr<libcamera::CameraConfiguration> config_;
>  
> +       libcamera::ControlList controls_;
> +
>         bool isRunning_;
>  
>         libcamera::Mutex bufferLock_;
> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> index 74bd54ce..493c41c0 100644
> --- a/src/v4l2/v4l2_camera_proxy.cpp
> +++ b/src/v4l2/v4l2_camera_proxy.cpp
> @@ -18,6 +18,8 @@
>  #include <unistd.h>
>  
>  #include <libcamera/camera.h>
> +#include <libcamera/controls.h>
> +#include <libcamera/control_ids.h>
>  #include <libcamera/formats.h>
>  
>  #include <libcamera/base/log.h>
> @@ -33,6 +35,7 @@
>  #define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))
>  
>  using namespace libcamera;
> +using namespace std::literals::chrono_literals;
>  
>  LOG_DECLARE_CATEGORY(V4L2Compat)
>  
> @@ -755,6 +758,23 @@ int V4L2CameraProxy::vidioc_streamoff(V4L2CameraFile *file, int *arg)
>         return ret;
>  }
>  
> +int V4L2CameraProxy::vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg)
> +{
> +       LOG(V4L2Compat, Debug)
> +               << "[" << file->description() << "] " << __func__ << "()";
> +
> +       if (!validateBufferType(arg->type))
> +               return -EINVAL;
> +
> +       struct v4l2_fract *timeperframe = &arg->parm.capture.timeperframe;
> +       utils::Duration frameDuration = 1.0s * timeperframe->numerator / timeperframe->denominator;
> +
> +       int64_t uDuration = frameDuration.get<std::micro>();
> +       vcam_->controls().set(controls::FrameDurationLimits, { uDuration, uDuration });
> +
> +       return 0;
> +}
> +
>  const std::set<unsigned long> V4L2CameraProxy::supportedIoctls_ = {
>         VIDIOC_QUERYCAP,
>         VIDIOC_ENUM_FRAMESIZES,
> @@ -775,6 +795,7 @@ const std::set<unsigned long> V4L2CameraProxy::supportedIoctls_ = {
>         VIDIOC_EXPBUF,
>         VIDIOC_STREAMON,
>         VIDIOC_STREAMOFF,
> +       VIDIOC_S_PARM,
>  };
>  
>  int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long request, void *arg)
> @@ -852,6 +873,9 @@ int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long request, void *ar
>         case VIDIOC_STREAMOFF:
>                 ret = vidioc_streamoff(file, static_cast<int *>(arg));
>                 break;
> +       case VIDIOC_S_PARM:
> +               ret = vidioc_s_parm(file, static_cast<struct v4l2_streamparm *>(arg));
> +               break;
>         default:
>                 ret = -ENOTTY;
>                 break;
> diff --git a/src/v4l2/v4l2_camera_proxy.h b/src/v4l2/v4l2_camera_proxy.h
> index 76ca2d8a..c1aeaff9 100644
> --- a/src/v4l2/v4l2_camera_proxy.h
> +++ b/src/v4l2/v4l2_camera_proxy.h
> @@ -65,6 +65,7 @@ private:
>         int vidioc_expbuf(V4L2CameraFile *file, struct v4l2_exportbuffer *arg);
>         int vidioc_streamon(V4L2CameraFile *file, int *arg);
>         int vidioc_streamoff(V4L2CameraFile *file, int *arg);
> +       int vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg);
>  
>         bool hasOwnership(V4L2CameraFile *file);
>         int acquire(V4L2CameraFile *file);
> -- 
> 2.17.1
>