libcamera: v4l2_subdevice: Add VIDIOC_SUBDEV_G_ROUTING ioctl

Signed-off-by: Phi-Bang Nguyen <pnguyen@baylibre.com>

2 files changed, 45 insertions, 0 deletions

diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
index 97b89fb9..7281b4bc 100644
--- a/include/libcamera/internal/v4l2_subdevice.h
+++ b/include/libcamera/internal/v4l2_subdevice.h
@@ -11,6 +11,8 @@
 #include <string>
 #include <vector>
 
+#include <linux/v4l2-subdev.h>
+
 #include <libcamera/base/class.h>
 #include <libcamera/base/log.h>
 
@@ -61,6 +63,9 @@ public:
 	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 		      Whence whence = ActiveFormat);
 
+	int getRouting(std::vector<struct v4l2_subdev_route> *routes,
+		       Whence whence = ActiveFormat);
+
 	static std::unique_ptr<V4L2Subdevice>
 	fromEntityName(const MediaDevice *media, const std::string &entity);
 
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 023e2328..a0cc5eb4 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -443,6 +443,46 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 }
 
 /**
+ * \brief Retrieve the subdevice's internal routing table
+ * \param[out] routes The routing table
+ * \param[in] whence The routing table to get, \ref V4L2Subdevice::ActiveFormat
+ * "ActiveFormat" or \ref V4L2Subdevice::TryFormat "TryFormat"
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Subdevice::getRouting(std::vector<struct v4l2_subdev_route> *routes,
+			      Whence whence)
+{
+	struct v4l2_subdev_routing rt = {};
+
+	rt.which = whence == ActiveFormat ? V4L2_SUBDEV_FORMAT_ACTIVE
+		 : V4L2_SUBDEV_FORMAT_TRY;
+
+	int ret = ioctl(VIDIOC_SUBDEV_G_ROUTING, &rt);
+	if (ret == 0 || ret == -ENOTTY)
+		return ret;
+
+	if (ret != -ENOSPC) {
+		LOG(V4L2, Error)
+			<< "Failed to retrieve number of routes: "
+			<< strerror(-ret);
+		return ret;
+	}
+
+	routes->resize(rt.num_routes);
+	rt.routes = reinterpret_cast<uintptr_t>(routes->data());
+
+	ret = ioctl(VIDIOC_SUBDEV_G_ROUTING, &rt);
+	if (ret) {
+		LOG(V4L2, Error)
+			<< "Failed to retrieve routes: " << strerror(-ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
  * \brief Create a new video subdevice instance from \a entity in media device
  * \a media
  * \param[in] media The media device where the entity is registered