diff mbox series

[PATCHv3,2/4] media-device: add media_device_devt function

Message ID 20210202144926.620104-3-hverkuil-cisco@xs4all.nl
State New
Headers show
Series Add /sys media_dev attr for V4L/DVB devices | expand

Commit Message

Hans Verkuil Feb. 2, 2021, 2:49 p.m. UTC 
Add a helper function for use by the DVB and V4L2 core frameworks
that safely returns the major and minor numbers of the media
device node, or 0 if the device node is not registered.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/mc/mc-device.c | 16 ++++++++++++++++
 include/media/media-device.h | 10 ++++++++++
 2 files changed, 26 insertions(+)
diff mbox series

Patch

diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
index 9e56d2ad6b94..2207f1b01456 100644
--- a/drivers/media/mc/mc-device.c
+++ b/drivers/media/mc/mc-device.c
@@ -850,6 +850,22 @@  void media_device_unregister(struct media_device *mdev)
 }
 EXPORT_SYMBOL_GPL(media_device_unregister);
 
+dev_t media_device_devt(struct media_device *mdev)
+{
+	dev_t devt = 0;
+
+	if (!mdev)
+		return 0;
+
+	mutex_lock(&mdev->graph_mutex);
+	/* Check if mdev is registered */
+	if (media_devnode_is_registered(mdev->devnode))
+		devt = mdev->devnode->dev.devt;
+	mutex_unlock(&mdev->graph_mutex);
+	return devt;
+}
+EXPORT_SYMBOL_GPL(media_device_devt);
+
 #if IS_ENABLED(CONFIG_PCI)
 void media_device_pci_init(struct media_device *mdev,
 			   struct pci_dev *pci_dev,
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 1345e6da688a..af089b1c55ef 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -300,6 +300,16 @@  int __must_check __media_device_register(struct media_device *mdev,
  */
 void media_device_unregister(struct media_device *mdev);
 
+/**
+ * media_device_devt() - return media device major/minor numbers
+ *
+ * @mdev:	pointer to struct &media_device
+ *
+ * Returns 0 if the media device node is not registered, otherwise
+ * it will return the major/minor number of the media device node.
+ */
+dev_t media_device_devt(struct media_device *mdev);
+
 /**
  * media_device_register_entity() - registers a media entity inside a
  *	previously registered media device.