[media] v4l: Add a media_device pointer to the v4l2_device structure

The pointer will later be used to register/unregister media entities
when registering/unregistering a v4l2_subdev or a video_device.

With the introduction of media devices, device drivers need to store a
pointer to a driver-specific structure in the device's drvdata.
v4l2_device can't claim ownership of the drvdata anymore.

To maintain compatibility with drivers that rely on v4l2_device storing
a pointer to itself in the device's drvdata, v4l2_device_register() will
keep doing so if the drvdata is NULL.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
index 8c0ad8b372d8..cfbd8a38991d 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -47,9 +47,8 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
         if (!v4l2_dev->name[0])
                 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
                         dev->driver->name, dev_name(dev));
-        if (dev_get_drvdata(dev))
-                v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");
-        dev_set_drvdata(dev, v4l2_dev);
+        if (!dev_get_drvdata(dev))
+                dev_set_drvdata(dev, v4l2_dev);
         return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register);
@@ -72,10 +71,12 @@ EXPORT_SYMBOL_GPL(v4l2_device_set_name);
 
 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
 {
-        if (v4l2_dev->dev) {
+        if (v4l2_dev->dev == NULL)
+                return;
+
+        if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
                 dev_set_drvdata(v4l2_dev->dev, NULL);
-                v4l2_dev->dev = NULL;
-        }
+        v4l2_dev->dev = NULL;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);