From 3d3fd89aabd81c1e33baf3dcf16329457cd82c77 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sun, 8 Mar 2009 21:02:10 +0100 Subject: v4l2-device: add a notify callback. From: Hans Verkuil Add a notify callback to v4l2_device to let sub-devices notify their parent of special events. Priority: normal Signed-off-by: Hans Verkuil --- linux/Documentation/video4linux/v4l2-framework.txt | 10 ++++++++++ linux/include/media/v4l2-device.h | 3 +++ linux/include/media/v4l2-subdev.h | 5 +++++ 3 files changed, 18 insertions(+) diff --git a/linux/Documentation/video4linux/v4l2-framework.txt b/linux/Documentation/video4linux/v4l2-framework.txt index accc376e9..1232f3066 100644 --- a/linux/Documentation/video4linux/v4l2-framework.txt +++ b/linux/Documentation/video4linux/v4l2-framework.txt @@ -93,6 +93,11 @@ The first 'dev' argument is normally the struct device pointer of a pci_dev, usb_device or platform_device. It is rare for dev to be NULL, but it happens with ISA devices, for example. +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/.h. + You unregister with: v4l2_device_unregister(struct v4l2_device *v4l2_dev); @@ -280,6 +285,11 @@ 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/linux/include/media/v4l2-device.h b/linux/include/media/v4l2-device.h index 5d7146dc2..3d8e96f6c 100644 --- a/linux/include/media/v4l2-device.h +++ b/linux/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/linux/include/media/v4l2-subdev.h b/linux/include/media/v4l2-subdev.h index 05b69652e..1b97a2c33 100644 --- a/linux/include/media/v4l2-subdev.h +++ b/linux/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 -- cgit v1.2.3