[v2,3/4] libcamera: media_device: Allow for a regex to match entity name
diff mbox series

Message ID 20250717124853.2317191-4-dan.scally@ideasonboard.com
State New
Headers show
Series
  • Use regular expressions for entity name matching
Related show

Commit Message

Daniel Scally July 17, 2025, 12:48 p.m. UTC
Some kernel drivers give their entities names that will differ from
implementation to implementation; for example the drivers for the
Camera Receiver Unit and CSI-2 receiver in the RZ/V2H SoC give their
entities names that include their memory address, in the format
"csi-16000400.csi2". Passing that entity name to
MediaDevice::getEntityByName() is too inflexible given it would only
then work if that specific CSI-2 receiver were the one being used.

Add an overload for MediaDevice::getEntityByName() that accepts a
std::basic_regex instead of a string, and use std::regex_search()
instead of a direct string comparison to find a matching entity. This
allows us to search for entites using regex patterns like
"csi-[0-9a-f]{8}.csi2".

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v2:

	- Add an overload for ::getEntityByName() instead of
	replacing the existing functionality. The new overload
	takes a regex, but will return a nullptr in the event
	that the given regex matches multiple entities.

 include/libcamera/internal/media_device.h |  2 ++
 src/libcamera/media_device.cpp            | 25 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)

Patch
diff mbox series

diff --git a/include/libcamera/internal/media_device.h b/include/libcamera/internal/media_device.h
index b3a48b98..3f28793f 100644
--- a/include/libcamera/internal/media_device.h
+++ b/include/libcamera/internal/media_device.h
@@ -14,6 +14,7 @@ 
 #include <linux/media.h>
 
 #include <libcamera/base/log.h>
+#include <libcamera/base/regex.h>
 #include <libcamera/base/signal.h>
 #include <libcamera/base/unique_fd.h>
 
@@ -45,6 +46,7 @@  public:
 
 	const std::vector<MediaEntity *> &entities() const { return entities_; }
 	MediaEntity *getEntityByName(const std::string &name) const;
+	MediaEntity *getEntityByName(const std::regex &name) const;
 
 	MediaLink *link(const std::string &sourceName, unsigned int sourceIdx,
 			const std::string &sinkName, unsigned int sinkIdx);
diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp
index 353f34a8..a0c0df86 100644
--- a/src/libcamera/media_device.cpp
+++ b/src/libcamera/media_device.cpp
@@ -341,6 +341,31 @@  MediaEntity *MediaDevice::getEntityByName(const std::string &name) const
 	return nullptr;
 }
 
+/**
+ * \brief Return the MediaEntity with name matching the regex \a name
+ * \param[in] name A regex to match the entity name
+ * \return The entity with name matching the regex \a name, or nullptr if no
+ * such entity is found
+ */
+MediaEntity *MediaDevice::getEntityByName(const std::regex &name) const
+{
+	MediaEntity *entity = nullptr;
+
+	for (MediaEntity *e : entities_) {
+		if (std::regex_search(e->name(), name)) {
+			if (entity) {
+				LOG(MediaDevice, Error)
+					<< "Multiple entities match given regex";
+				return nullptr;
+			}
+
+			entity = e;
+		}
+	}
+
+	return entity;
+}
+
 /**
  * \brief Retrieve the MediaLink connecting two pads, identified by entity
  * names and pad indexes