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[media] v4l2-framework: replace g_chip_ident by g_std in the examples

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The framework documentation used the g_chip_ident op as an example. This
op has been removed, so replace its use in the examples by the g_std op.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil
2013-05-29 07:59:57 -03:00
committed by Mauro Carvalho Chehab
parent abbec2d401
commit 2249aa5c97
2 changed files with 12 additions and 14 deletions
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13
Documentation/video4linux/v4l2-framework.txt
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@@ -246,7 +246,6 @@ may be NULL if the subdev driver does not support anything from that category.
It looks like this:
struct v4l2_subdev_core_ops {
int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_dbg_chip_ident *chip);
int (*log_status)(struct v4l2_subdev *sd);
int (*init)(struct v4l2_subdev *sd, u32 val);
...
@@ -346,24 +345,24 @@ Afterwards the subdev module can be unloaded and sd->dev == NULL.
You can call an ops function either directly:
err = sd->ops->core->g_chip_ident(sd, &chip);
err = sd->ops->core->g_std(sd, &norm);
but it is better and easier to use this macro:
err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
err = v4l2_subdev_call(sd, core, g_std, &norm);
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
NULL, or the actual result of the subdev->ops->core->g_chip_ident ops.
is NULL, -ENOIOCTLCMD if either subdev->core or subdev->core->g_std is
NULL, or the actual result of the subdev->ops->core->g_std ops.
It is also possible to call all or a subset of the sub-devices:
v4l2_device_call_all(v4l2_dev, 0, core, g_chip_ident, &chip);
v4l2_device_call_all(v4l2_dev, 0, core, g_std, &norm);
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(v4l2_dev, 0, core, g_chip_ident, &chip);
err = v4l2_device_call_until_err(v4l2_dev, 0, core, g_std, &norm);
Any error except -ENOIOCTLCMD will exit the loop with that error. If no
errors (except -ENOIOCTLCMD) occurred, then 0 is returned.