3 files changed, 64 insertions, 2 deletions

diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h
index e54371fb..9bd161b9 100644
--- a/src/v4l2/v4l2_camera.h
+++ b/src/v4l2/v4l2_camera.h
@@ -52,6 +52,7 @@ public:
 				  libcamera::StreamConfiguration *streamConfigOut);
 
 	libcamera::ControlList &controls() { return controls_; }
+	const libcamera::ControlInfoMap &controlInfo() { return camera_->controls(); }
 
 	int allocBuffers(unsigned int count);
 	void freeBuffers();
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 5ac8df4c..559ffc61 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -195,6 +195,29 @@ void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
 	v4l2PixFormat_.xfer_func    = V4L2_XFER_FUNC_DEFAULT;
 
 	sizeimage_ = streamConfig.frameSize;
+
+	const ControlInfoMap &controls = vcam_->controlInfo();
+	const auto &it = controls.find(&controls::FrameDurationLimits);
+
+	if (it != controls.end()) {
+		const int64_t duration = it->second.def().get<int64_t>();
+
+		v4l2TimePerFrame_.numerator = duration;
+		v4l2TimePerFrame_.denominator = 1000000;
+	} else {
+		/*
+		 * Default to 30fps if the camera doesn't expose the
+		 * FrameDurationLimits control.
+		 *
+		 * \todo Remove this once all pipeline handlers implement the
+		 * control
+		 */
+		LOG(V4L2Compat, Warning)
+			<< "Camera does not support FrameDurationLimits";
+
+		v4l2TimePerFrame_.numerator = 333333;
+		v4l2TimePerFrame_.denominator = 1000000;
+	}
 }
 
 void V4L2CameraProxy::querycap(std::shared_ptr<Camera> camera)
@@ -758,6 +781,22 @@ int V4L2CameraProxy::vidioc_streamoff(V4L2CameraFile *file, int *arg)
 	return ret;
 }
 
+int V4L2CameraProxy::vidioc_g_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg)
+{
+	LOG(V4L2Compat, Debug)
+		<< "[" << file->description() << "] " << __func__ << "()";
+
+	if (!validateBufferType(arg->type))
+		return -EINVAL;
+
+	memset(&arg->parm, 0, sizeof(arg->parm));
+
+	arg->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
+	arg->parm.capture.timeperframe = v4l2TimePerFrame_;
+
+	return 0;
+}
+
 int V4L2CameraProxy::vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg)
 {
 	LOG(V4L2Compat, Debug)
@@ -766,9 +805,25 @@ int V4L2CameraProxy::vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm
 	if (!validateBufferType(arg->type))
 		return -EINVAL;
 
-	struct v4l2_fract *timeperframe = &arg->parm.capture.timeperframe;
-	utils::Duration frameDuration = 1.0s * timeperframe->numerator / timeperframe->denominator;
+	/*
+	 * Store the frame duration if it is valid, otherwise keep the current
+	 * value.
+	 *
+	 * \todo The provided value should be adjusted based on the camera
+	 * capabilities.
+	 */
+	if (arg->parm.capture.timeperframe.numerator &&
+	    arg->parm.capture.timeperframe.denominator)
+		v4l2TimePerFrame_ = arg->parm.capture.timeperframe;
+
+	memset(&arg->parm, 0, sizeof(arg->parm));
 
+	arg->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
+	arg->parm.capture.timeperframe = v4l2TimePerFrame_;
+
+	/* Apply the frame duration. */
+	utils::Duration frameDuration = 1.0s * v4l2TimePerFrame_.numerator
+				      / v4l2TimePerFrame_.denominator;
 	int64_t uDuration = frameDuration.get<std::micro>();
 	vcam_->controls().set(controls::FrameDurationLimits, { uDuration, uDuration });
 
@@ -795,6 +850,7 @@ const std::set<unsigned long> V4L2CameraProxy::supportedIoctls_ = {
 	VIDIOC_EXPBUF,
 	VIDIOC_STREAMON,
 	VIDIOC_STREAMOFF,
+	VIDIOC_G_PARM,
 	VIDIOC_S_PARM,
 };
 
@@ -883,6 +939,9 @@ int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long longRequest, void
 	case VIDIOC_STREAMOFF:
 		ret = vidioc_streamoff(file, static_cast<int *>(arg));
 		break;
+	case VIDIOC_G_PARM:
+		ret = vidioc_g_parm(file, static_cast<struct v4l2_streamparm *>(arg));
+		break;
 	case VIDIOC_S_PARM:
 		ret = vidioc_s_parm(file, static_cast<struct v4l2_streamparm *>(arg));
 		break;
diff --git a/src/v4l2/v4l2_camera_proxy.h b/src/v4l2/v4l2_camera_proxy.h
index c957db53..5aa352c3 100644
--- a/src/v4l2/v4l2_camera_proxy.h
+++ b/src/v4l2/v4l2_camera_proxy.h
@@ -67,6 +67,7 @@ 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_g_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg);
 	int vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg);
 
 	bool hasOwnership(V4L2CameraFile *file);
@@ -85,6 +86,7 @@ private:
 
 	struct v4l2_capability capabilities_;
 	struct v4l2_pix_format v4l2PixFormat_;
+	struct v4l2_fract v4l2TimePerFrame_;
 
 	std::vector<struct v4l2_buffer> buffers_;
 	std::map<void *, unsigned int> mmaps_;