libcamera: v4l2_device: Move start of frame detection to V4L2Device

The V4L2_EVENT_FRAME_SYNC event may occur on both V4L2 video-devices
(V4L2VideoDevice) and sub-devices (V4L2Subdevice). Move the start of
frame detection to the common base class of the two, V4L2Device.

There is no functional change.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

include/libcamera/internal/v4l2_device.h

@@ -13,11 +13,15 @@
 
 #include <linux/videodev2.h>
 
+#include <libcamera/signal.h>
+
 #include "libcamera/internal/log.h"
 #include "libcamera/internal/v4l2_controls.h"
 
 namespace libcamera {
 
+class EventNotifier;
+
 class V4L2Device : protected Loggable
 {
 public:
@@ -34,6 +38,9 @@ public:
 	const std::string &deviceNode() const { return deviceNode_; }
 	std::string devicePath() const;
 
+	int setFrameStartEnabled(bool enable);
+	Signal<uint32_t> frameStart;
+
 protected:
 	V4L2Device(const std::string &deviceNode);
 	~V4L2Device();
@@ -51,11 +58,16 @@ private:
 			    const struct v4l2_ext_control *v4l2Ctrls,
 			    unsigned int count);
 
+	void eventAvailable(EventNotifier *notifier);
+
 	std::map<unsigned int, struct v4l2_query_ext_ctrl> controlInfo_;
 	std::vector<std::unique_ptr<V4L2ControlId>> controlIds_;
 	ControlInfoMap controls_;
 	std::string deviceNode_;
 	int fd_;
+
+	EventNotifier *fdEventNotifier_;
+	bool frameStartEnabled_;
 };
 
 } /* namespace libcamera */

include/libcamera/internal/v4l2_videodevice.h

@@ -207,9 +207,6 @@ public:
 	int queueBuffer(FrameBuffer *buffer);
 	Signal<FrameBuffer *> bufferReady;
 
-	int setFrameStartEnabled(bool enable);
-	Signal<uint32_t> frameStart;
-
 	int streamOn();
 	int streamOff();
 
@@ -243,8 +240,6 @@ private:
 	void bufferAvailable(EventNotifier *notifier);
 	FrameBuffer *dequeueBuffer();
 
-	void eventAvailable(EventNotifier *notifier);
-
 	V4L2Capability caps_;
 
 	enum v4l2_buf_type bufferType_;
@@ -254,9 +249,6 @@ private:
 	std::map<unsigned int, FrameBuffer *> queuedBuffers_;
 
 	EventNotifier *fdBufferNotifier_;
-	EventNotifier *fdEventNotifier_;
-
-	bool frameStartEnabled_;
 };
 
 class V4L2M2MDevice