libcamera: camera_sensor: Verify flips support

During the camera sensor driver validation, verify if the sensor
supports horizontal and vertical flips and store a flag as
CameraSensor::supportFlips_ class member.

The flag will be later inspected when applying flips.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>

include/libcamera/internal/camera_sensor.h

@@ -101,6 +101,7 @@ private:
 	Size pixelArraySize_;
 	Rectangle activeArea_;
 	const BayerFormat *bayerFormat_;
+	bool supportFlips_;
 
 	ControlList properties_;
 

src/libcamera/camera_sensor.cpp

@@ -55,7 +55,8 @@ LOG_DEFINE_CATEGORY(CameraSensor)
  */
 CameraSensor::CameraSensor(const MediaEntity *entity)
 	: entity_(entity), pad_(UINT_MAX), staticProps_(nullptr),
-	  bayerFormat_(nullptr), properties_(properties::properties)
+	  bayerFormat_(nullptr), supportFlips_(false),
+	  properties_(properties::properties)
 {
 }
 
@@ -247,6 +248,21 @@ int CameraSensor::validateSensorDriver()
 		}
 	}
 
+	/*
+	 * Verify if sensor supports horizontal/vertical flips
+	 *
+	 * \todo Handle horizontal and vertical flips independently.
+	 */
+	const struct v4l2_query_ext_ctrl *hflipInfo = subdev_->controlInfo(V4L2_CID_HFLIP);
+	const struct v4l2_query_ext_ctrl *vflipInfo = subdev_->controlInfo(V4L2_CID_VFLIP);
+	if (hflipInfo && !(hflipInfo->flags & V4L2_CTRL_FLAG_READ_ONLY) &&
+	    vflipInfo && !(vflipInfo->flags & V4L2_CTRL_FLAG_READ_ONLY))
+		supportFlips_ = true;
+
+	if (!supportFlips_)
+		LOG(CameraSensor, Warning)
+			<< "Camera sensor does not support horizontal/vertical flip";
+
 	/*
 	 * Make sure the required selection targets are supported.
 	 *