diff options
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 10 | ||||
| -rw-r--r-- | include/media/v4l2-device.h | 3 | ||||
| -rw-r--r-- | include/media/v4l2-subdev.h | 5 |
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 |