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-rw-r--r--Documentation/video4linux/v4l2-framework.txt10
-rw-r--r--include/media/v4l2-device.h3
-rw-r--r--include/media/v4l2-subdev.h5
3 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index df0247ed13d..4207590b2ac 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -94,6 +94,11 @@ usb_device or platform_device. It is rare for dev to be NULL, but it happens
with ISA devices or when one device creates multiple PCI devices, thus making
it impossible to associate v4l2_dev with a particular parent.
+You can also supply a notify() callback that can be called by sub-devices to
+notify you of events. Whether you need to set this depends on the sub-device.
+Any notifications a sub-device supports must be defined in a header in
+include/media/<subdevice>.h.
+
You unregister with:
v4l2_device_unregister(struct v4l2_device *v4l2_dev);
@@ -281,6 +286,11 @@ e.g. AUDIO_CONTROLLER and specify that as the group ID value when calling
v4l2_device_call_all(). That ensures that it will only go to the subdev
that needs it.
+If the sub-device needs to notify its v4l2_device parent of an event, then
+it can call v4l2_subdev_notify(sd, notification, arg). This macro checks
+whether there is a notify() callback defined and returns -ENODEV if not.
+Otherwise the result of the notify() call is returned.
+
The advantage of using v4l2_subdev is that it is a generic struct and does
not contain any knowledge about the underlying hardware. So a driver might
contain several subdevs that use an I2C bus, but also a subdev that is
diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
index 5d7146dc291..3d8e96f6ceb 100644
--- a/include/media/v4l2-device.h
+++ b/include/media/v4l2-device.h
@@ -44,6 +44,9 @@ struct v4l2_device {
spinlock_t lock;
/* unique device name, by default the driver name + bus ID */
char name[V4L2_DEVICE_NAME_SIZE];
+ /* notify callback called by some sub-devices. */
+ void (*notify)(struct v4l2_subdev *sd,
+ unsigned int notification, void *arg);
};
/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 05b69652e6c..1b97a2c33a7 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -191,4 +191,9 @@ static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
(!(sd) ? -ENODEV : (((sd) && (sd)->ops->o && (sd)->ops->o->f) ? \
(sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))
+/* Send a notification to v4l2_device. */
+#define v4l2_subdev_notify(sd, notification, arg) \
+ ((!(sd) || !(sd)->v4l2_dev || !(sd)->v4l2_dev->notify) ? -ENODEV : \
+ (sd)->v4l2_dev->notify((sd), (notification), (arg)))
+
#endif