[libcamera-devel] [PATCH 4/5] libcamera: v4l2_subdevice: Add G_SELECTION ioctl support

[Jacopo Mondi]

Add a private operation to perform G_SELECTION ioctl on the v4l2
subdevice and create two public methods to retrieve the crop bound
rectangle and the subdevice native area size.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/include/v4l2_subdevice.h |  4 +++
 src/libcamera/v4l2_subdevice.cpp       | 48 ++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 9c077674f997..5316617c6873 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -43,6 +43,8 @@ public:
 
 	int setCrop(unsigned int pad, Rectangle *rect);
 	int setCompose(unsigned int pad, Rectangle *rect);
+	int getCropBounds(unsigned int pad, Rectangle *rect);
+	int getNativeSize(unsigned int pad, Rectangle *rect);
 
 	ImageFormats formats(unsigned int pad);
 
@@ -62,6 +64,8 @@ private:
 
 	int setSelection(unsigned int pad, unsigned int target,
 			 Rectangle *rect);
+	int getSelection(unsigned int pad, unsigned int target,
+			 Rectangle *rect);
 
 	const MediaEntity *entity_;
 };
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index a188298de34c..5e661e2ef1fc 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -148,6 +148,28 @@ int V4L2Subdevice::setCompose(unsigned int pad, Rectangle *rect)
 	return setSelection(pad, V4L2_SEL_TGT_COMPOSE, rect);
 }
 
+/**
+ * \brief Get the crop bounds rectangle on one of the V4L2 subdevice pads
+ * \param[in] pad The 0-indexed pad number the rectangle is retrived from
+ * \param[out] rect The rectangle describing the crop bounds area
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Subdevice::getCropBounds(unsigned int pad, Rectangle *rect)
+{
+	return getSelection(pad, V4L2_SEL_TGT_CROP_BOUNDS, rect);
+}
+
+/**
+ * \brief Get the native area size on one of the V4L2 subdevice pads
+ * \param[in] pad The 0-indexed pad number the native area is retrieved from
+ * \param[out] rect The rectangle describing the native size area
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Subdevice::getNativeSize(unsigned int pad, Rectangle *rect)
+{
+	return getSelection(pad, V4L2_SEL_TGT_NATIVE_SIZE, rect);
+}
+
 /**
  * \brief Enumerate all media bus codes and frame sizes on a \a pad
  * \param[in] pad The 0-indexed pad number to enumerate formats on
@@ -360,4 +382,30 @@ int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
 	return 0;
 }
 
+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) {
+		LOG(V4L2, Error)
+			<< "Unable to get rectangle " << target << " on pad "
+			<< pad << ": " << strerror(-ret);
+		return ret;
+	}
+
+	rect->x = sel.r.left;
+	rect->y = sel.r.top;
+	rect->w = sel.r.width;
+	rect->h = sel.r.height;
+
+	return 0;
+}
+
 } /* namespace libcamera */
-- 
2.22.0