关于宏v4l2

struct v4l2_subdev *sd结构体 

struct v4l2_subdev {
#if defined(CONFIG_MEDIA_CONTROLLER)
	struct media_entity entity;
#endif
	struct list_head list;
	struct module *owner;
	bool owner_v4l2_dev;
	u32 flags;
	struct v4l2_device *v4l2_dev;
	const struct v4l2_subdev_ops *ops;
	const struct v4l2_subdev_internal_ops *internal_ops;
	struct v4l2_ctrl_handler *ctrl_handler;
	char name[V4L2_SUBDEV_NAME_SIZE];
	u32 grp_id;
	void *dev_priv;
	void *host_priv;
	struct video_device *devnode;
	struct device *dev;
	struct fwnode_handle *fwnode;
	struct list_head async_list;
	struct v4l2_async_subdev *asd;
	struct v4l2_async_notifier *notifier;
	struct v4l2_async_notifier *subdev_notifier;
	struct v4l2_subdev_platform_data *pdata;
};

sd->ops

    if(sd->ops == NULL){
			DEBUG_CORE("sd->ops NULL");
			break;
		}

然后看看 v4l2_subdev_ops 的定义

static const struct v4l2_subdev_ops ov5645_subdev_ops = {
	.core = &ov5645_core_ops,
	.video = &ov5645_video_ops,
	.pad = &ov5645_subdev_pad_ops,
};

  if(sd->ops->core == NULL){
			DEBUG_CORE("sd->ops->core NULL");
			break;
		}

最后判断ioctl是否为空

if(sd->ops->core->ioctl == NULL){
			DEBUG_CORE("sd->ops->core NULL");
			break;
		}
		sd->ops->core->ioctl(sd, ctrl->id, &ctrl->val);

小结

最后把 v4l2_subdev_call(sd, core, ioctl, ctrl->id,ctrl->val);

转换为了 sd->ops->core->ioctl(sd, ctrl->id, &ctrl->val);

转换这个主要是为了空指针检查。解决问题了以后，还是用原来的宏就行了。