libcamera: converter_v4l2_m2m: Refactor get crop bounds code

In an upcoming patch it is necessary to get the crop bounds on the
converter itself. The V4L2M2MConverter contains code that is very
similar to the get crop bounds code in the V4L2M2MStream. Merge these
code blocks into a static function to be used from both classes.  This
patch contains no functional changes.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 52 insertions, 54 deletions

diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
index d63ef2f8..8c341fe1 100644
--- a/src/libcamera/converter/converter_v4l2_m2m.cpp
+++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
@@ -30,6 +30,52 @@ namespace libcamera {
 
 LOG_DECLARE_CATEGORY(Converter)
 
+namespace {
+
+int getCropBounds(V4L2VideoDevice *device, Rectangle &minCrop,
+		  Rectangle &maxCrop)
+{
+	Rectangle minC;
+	Rectangle maxC;
+
+	/* Find crop bounds */
+	minC.width = 1;
+	minC.height = 1;
+	maxC.width = UINT_MAX;
+	maxC.height = UINT_MAX;
+
+	int ret = device->setSelection(V4L2_SEL_TGT_CROP, &minC);
+	if (ret) {
+		LOG(Converter, Error)
+			<< "Could not query minimum selection crop: "
+			<< strerror(-ret);
+		return ret;
+	}
+
+	ret = device->getSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxC);
+	if (ret) {
+		LOG(Converter, Error)
+			<< "Could not query maximum selection crop: "
+			<< strerror(-ret);
+		return ret;
+	}
+
+	/* Reset the crop to its maximum */
+	ret = device->setSelection(V4L2_SEL_TGT_CROP, &maxC);
+	if (ret) {
+		LOG(Converter, Error)
+			<< "Could not reset selection crop: "
+			<< strerror(-ret);
+		return ret;
+	}
+
+	minCrop = minC;
+	maxCrop = maxC;
+	return 0;
+}
+
+} /* namespace */
+
 /* -----------------------------------------------------------------------------
  * V4L2M2MConverter::V4L2M2MStream
  */
@@ -98,41 +144,10 @@ int V4L2M2MConverter::V4L2M2MStream::configure(const StreamConfiguration &inputC
 	outputBufferCount_ = outputCfg.bufferCount;
 
 	if (converter_->features() & Feature::InputCrop) {
-		Rectangle minCrop;
-		Rectangle maxCrop;
-
-		/* Find crop bounds */
-		minCrop.width = 1;
-		minCrop.height = 1;
-		maxCrop.width = UINT_MAX;
-		maxCrop.height = UINT_MAX;
-
-		ret = setInputSelection(V4L2_SEL_TGT_CROP, &minCrop);
-		if (ret) {
-			LOG(Converter, Error)
-				<< "Could not query minimum selection crop: "
-				<< strerror(-ret);
-			return ret;
-		}
-
-		ret = getInputSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxCrop);
-		if (ret) {
-			LOG(Converter, Error)
-				<< "Could not query maximum selection crop: "
-				<< strerror(-ret);
+		ret = getCropBounds(m2m_->output(), inputCropBounds_.first,
+				    inputCropBounds_.second);
+		if (ret)
 			return ret;
-		}
-
-		/* Reset the crop to its maximum */
-		ret = setInputSelection(V4L2_SEL_TGT_CROP, &maxCrop);
-		if (ret) {
-			LOG(Converter, Error)
-				<< "Could not reset selection crop: "
-				<< strerror(-ret);
-			return ret;
-		}
-
-		inputCropBounds_ = { minCrop, maxCrop };
 	}
 
 	return 0;
@@ -258,27 +273,10 @@ V4L2M2MConverter::V4L2M2MConverter(MediaDevice *media)
 		return;
 	}
 
-	/* Discover Feature::InputCrop */
+	Rectangle minCrop;
 	Rectangle maxCrop;
-	maxCrop.width = UINT_MAX;
-	maxCrop.height = UINT_MAX;
-
-	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &maxCrop);
-	if (ret)
-		return;
-
-	/*
-	 * Rectangles for cropping targets are defined even if the device
-	 * does not support cropping. Their sizes and positions will be
-	 * fixed in such cases.
-	 *
-	 * Set and inspect a crop equivalent to half of the maximum crop
-	 * returned earlier. Use this to determine whether the crop on
-	 * input is really supported.
-	 */
-	Rectangle halfCrop(maxCrop.size() / 2);
-	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &halfCrop);
-	if (!ret && halfCrop != maxCrop) {
+	ret = getCropBounds(m2m_->output(), minCrop, maxCrop);
+	if (!ret && minCrop != maxCrop) {
 		features_ |= Feature::InputCrop;
 
 		LOG(Converter, Info)