[libcamera-devel] [PATCH v3 04/13] libcamera: v4l2_subdevice: Implement get selection

[Jacopo Mondi]

Implement get selection for the V4L2Subdevice class to support
retrieving three targets: the subdevice native size, the analog crop and
the active pixel area.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/include/v4l2_subdevice.h |  6 ++
 src/libcamera/v4l2_subdevice.cpp       | 92 ++++++++++++++++++++++++++
 2 files changed, 98 insertions(+)

diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 4a04eadfb1f9..763ffadb61fb 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -46,6 +46,10 @@ public:
 
 	const MediaEntity *entity() const { return entity_; }
 
+	int getNativeSize(unsigned int pad, Size *size);
+	int getActiveArea(unsigned int pad, Rectangle *rect);
+	int getCropRectangle(unsigned int pad, Rectangle *rect);
+
 	int setCrop(unsigned int pad, Rectangle *rect);
 	int setCompose(unsigned int pad, Rectangle *rect);
 
@@ -67,6 +71,8 @@ private:
 	std::vector<SizeRange> enumPadSizes(unsigned int pad,
 					    unsigned int code);
 
+	int getSelection(unsigned int pad, unsigned int target,
+			 Rectangle *rect);
 	int setSelection(unsigned int pad, unsigned int target,
 			 Rectangle *rect);
 
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 5a479a96b795..4dcf8ce48754 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -133,6 +133,68 @@ int V4L2Subdevice::open()
  * \return The subdevice's associated media entity.
  */
 
+/**
+ * \brief Get the sub-device native size
+ * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
+ * \param[out] size The sub-device native area size
+ *
+ * Retrieve the size of the sub-device native area.
+ * If the sub-device represent an image sensor, the native area describes
+ * the pixel array dimensions, including inactive and calibration pixels.
+ *
+ * \return 0 on success or a negative error code otherwise
+ * \retval -ENOTTY The native size information is not available
+ */
+int V4L2Subdevice::getNativeSize(unsigned int pad, Size *size)
+{
+	Rectangle rect = {};
+	int ret = getSelection(pad, V4L2_SEL_TGT_NATIVE_SIZE, &rect);
+	if (ret)
+		return ret;
+
+	size->width = rect.width;
+	size->height = rect.height;
+
+	return 0;
+}
+
+/**
+ * \brief Get the active area rectangle
+ * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
+ * \param[out] rect The rectangle describing the sub-device active area
+ *
+ * Retrieve the rectangle describing the sub-device active area.
+ * If the sub-device represent an image sensor, the active area describes
+ * the pixel array active portion.
+ *
+ * The returned \a rect 'x' and 'y' fields represent the displacement from the
+ * native size rectangle top-left corner.
+ *
+ * \return 0 on success or a negative error code otherwise
+ * \retval -ENOTTY The active areas size information is not available
+ */
+int V4L2Subdevice::getActiveArea(unsigned int pad, Rectangle *rect)
+{
+	return getSelection(pad, V4L2_SEL_TGT_CROP_DEFAULT, rect);
+}
+
+/**
+ * \brief Get the crop rectangle
+ * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
+ * \param[out] rect The rectangle describing the cropped area rectangle
+ *
+ * Retrieve the rectangle representing the cropped area. If the sub-device
+ * represents an image sensor, the cropped area describes the pixel array
+ * portion from which the final image is produced from.
+ *
+ * \return 0 on success or a negative error code otherwise
+ * \retval -ENOTTY The crop rectangle size information is not available
+ */
+int V4L2Subdevice::getCropRectangle(unsigned int pad, Rectangle *rect)
+{
+	return getSelection(pad, V4L2_SEL_TGT_CROP, rect);
+}
+
 /**
  * \brief Set a crop rectangle on one of the V4L2 subdevice pads
  * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
@@ -343,6 +405,36 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
 	return sizes;
 }
 
+int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
+				Rectangle *rect)
+{
+	struct v4l2_subdev_selection sel = {};
+
+	sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
+	sel.pad = pad;
+	sel.target = target;
+	sel.flags = 0;
+
+	int ret = ioctl(VIDIOC_SUBDEV_G_SELECTION, &sel);
+	if (ret < 0 && ret != -ENOTTY) {
+		LOG(V4L2, Error)
+			<< "Unable to get rectangle " << target << " on pad "
+			<< pad << ": " << strerror(-ret);
+		return ret;
+	}
+	if (ret == -ENOTTY) {
+		LOG(V4L2, Debug) << "Selection API not available";
+		return ret;
+	}
+
+	rect->x = sel.r.left;
+	rect->y = sel.r.top;
+	rect->width = sel.r.width;
+	rect->height = sel.r.height;
+
+	return 0;
+}
+
 int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
 				Rectangle *rect)
 {
-- 
2.26.1