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Commit 2249aa5c authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] v4l2-framework: replace g_chip_ident by g_std in the examples 



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: default avatarHans Verkuil <hans.verkuil@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent abbec2d4

Documentation/video4linux/v4l2-framework.txt

+6 −7
Original line number Diff line number Diff line
@@ -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.

Documentation/zh_CN/video4linux/v4l2-framework.txt

+6 −7
Original line number Diff line number Diff line
@@ -247,7 +247,6 @@ i2c_client 结构体，i2c_set_clientdata() 函数可用于保存一个 v4l2_sub 
这些结构体定义如下：



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);

	...
@@ -337,24 +336,24 @@ subdev->dev 域就指向了 v4l2_device。 


注册之设备后，可通过以下方式直接调用其操作函数：



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

	err = sd->ops->core->g_std(sd, &norm);



但使用如下宏会比较容易且合适：



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

	err = v4l2_subdev_call(sd, core, g_std, &norm);



这个宏将会做 NULL 指针检查，如果 subdev 为 NULL，则返回-ENODEV；如果

subdev->core 或 subdev->core->g_chip_ident 为 NULL，则返回 -ENOIOCTLCMD；

否则将返回 subdev->ops->core->g_chip_ident ops 调用的实际结果。

subdev->core 或 subdev->core->g_std 为 NULL，则返回 -ENOIOCTLCMD；

否则将返回 subdev->ops->core->g_std ops 调用的实际结果。



有时也可能同时调用所有或一系列子设备的某个操作函数：



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

	v4l2_device_call_all(v4l2_dev, 0, core, g_std, &norm);



任何不支持此操作的子设备都会被跳过，并忽略错误返回值。但如果你需要

检查出错码，则可使用如下函数：



	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);



除 -ENOIOCTLCMD 外的任何错误都会跳出循环并返回错误值。如果（除 -ENOIOCTLCMD

外）没有错误发生，则返回 0。