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);
...
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.