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Commit 89aec3e1 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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V4L/DVB (10489): doc: use consistent naming conventions for vdev and v4l2_dev. 



Signed-off-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 8ac05ae3

Documentation/video4linux/v4l2-framework.txt

+11 −11
Original line number Diff line number Diff line
@@ -134,7 +134,7 @@ The recommended approach is as follows: 


static atomic_t drv_instance = ATOMIC_INIT(0);



static int __devinit drv_probe(struct pci_dev *dev,

static int __devinit drv_probe(struct pci_dev *pdev,

				const struct pci_device_id *pci_id)

{

	...
@@ -218,7 +218,7 @@ to add new ops and categories. 


A sub-device driver initializes the v4l2_subdev struct using:



	v4l2_subdev_init(subdev, &ops);

	v4l2_subdev_init(sd, &ops);



Afterwards you need to initialize subdev->name with a unique name and set the

module owner. This is done for you if you use the i2c helper functions.
@@ -226,7 +226,7 @@ module owner. This is done for you if you use the i2c helper functions. 
A device (bridge) driver needs to register the v4l2_subdev with the

v4l2_device:



	int err = v4l2_device_register_subdev(device, subdev);

	int err = v4l2_device_register_subdev(v4l2_dev, sd);



This can fail if the subdev module disappeared before it could be registered.

After this function was called successfully the subdev->dev field points to
@@ -234,17 +234,17 @@ the v4l2_device. 


You can unregister a sub-device using:



	v4l2_device_unregister_subdev(subdev);

	v4l2_device_unregister_subdev(sd);



Afterwards the subdev module can be unloaded and subdev->dev == NULL.

Afterwards the subdev module can be unloaded and sd->dev == NULL.



You can call an ops function either directly:



	err = subdev->ops->core->g_chip_ident(subdev, &chip);

	err = sd->ops->core->g_chip_ident(sd, &chip);



but it is better and easier to use this macro:



	err = v4l2_subdev_call(subdev, core, g_chip_ident, &chip);

	err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);



The macro will to the right NULL pointer checks and returns -ENODEV if subdev

is NULL, -ENOIOCTLCMD if either subdev->core or subdev->core->g_chip_ident is
@@ -252,12 +252,12 @@ NULL, or the actual result of the subdev->ops->core->g_chip_ident ops. 


It is also possible to call all or a subset of the sub-devices:



	v4l2_device_call_all(dev, 0, core, g_chip_ident, &chip);

	v4l2_device_call_all(v4l2_dev, 0, core, g_chip_ident, &chip);



Any subdev that does not support this ops is skipped and error results are

ignored. If you want to check for errors use this:



	err = v4l2_device_call_until_err(dev, 0, core, g_chip_ident, &chip);

	err = v4l2_device_call_until_err(v4l2_dev, 0, core, g_chip_ident, &chip);



Any error except -ENOIOCTLCMD will exit the loop with that error. If no

errors (except -ENOIOCTLCMD) occured, then 0 is returned.
@@ -505,8 +505,8 @@ There are a few useful helper functions: 


You can set/get driver private data in the video_device struct using:



void *video_get_drvdata(struct video_device *dev);

void video_set_drvdata(struct video_device *dev, void *data);

void *video_get_drvdata(struct video_device *vdev);

void video_set_drvdata(struct video_device *vdev, void *data);



Note that you can safely call video_set_drvdata() before calling

video_register_device().