[v3,13/14] media: v4l2-async: Discourage use of v4l2_async_notifier_add_subdev

From: Ezequiel Garcia <ezequiel@collabora.com>

Most -if not all- use-cases are expected to be covered by one of:
v4l2_async_notifier_add_fwnode_subdev,
v4l2_async_notifier_add_fwnode_remote_subdev or
v4l2_async_notifier_add_i2c_subdev.

We'd like to discourage drivers from using v4l2_async_notifier_add_subdev,
so rename it as __v4l2_async_notifier_add_subdev. This is
typically a good hint for drivers to avoid using the function.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-async.c  | 8 ++++----
 drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
 include/media/v4l2-async.h            | 9 +++++++--
 3 files changed, 12 insertions(+), 7 deletions(-)

On 1/25/21 10:22 AM, Sakari Ailus wrote:
> From: Ezequiel Garcia <ezequiel@collabora.com>
> 
> Most -if not all- use-cases are expected to be covered by one of:
> v4l2_async_notifier_add_fwnode_subdev,
> v4l2_async_notifier_add_fwnode_remote_subdev or
> v4l2_async_notifier_add_i2c_subdev.
> 
> We'd like to discourage drivers from using v4l2_async_notifier_add_subdev,
> so rename it as __v4l2_async_notifier_add_subdev. This is
> typically a good hint for drivers to avoid using the function.
> 
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Reviewed-by: Helen Koike <helen.koike@collabora.com>

> ---
>  drivers/media/v4l2-core/v4l2-async.c  | 8 ++++----
>  drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
>  include/media/v4l2-async.h            | 9 +++++++--
>  3 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 1f2b7aa1fca6..bd1944c2d062 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -603,7 +603,7 @@ void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
>  
> -int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
> +int __v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
>  				   struct v4l2_async_subdev *asd)
>  {
>  	int ret;
> @@ -620,7 +620,7 @@ int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
>  	mutex_unlock(&list_lock);
>  	return ret;
>  }
> -EXPORT_SYMBOL_GPL(v4l2_async_notifier_add_subdev);
> +EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_subdev);
>  
>  struct v4l2_async_subdev *
>  v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
> @@ -637,7 +637,7 @@ v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
>  	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
>  	asd->match.fwnode = fwnode_handle_get(fwnode);
>  
> -	ret = v4l2_async_notifier_add_subdev(notifier, asd);
> +	ret = __v4l2_async_notifier_add_subdev(notifier, asd);
>  	if (ret) {
>  		fwnode_handle_put(fwnode);
>  		kfree(asd);
> @@ -687,7 +687,7 @@ v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier,
>  	asd->match.i2c.adapter_id = adapter_id;
>  	asd->match.i2c.address = address;
>  
> -	ret = v4l2_async_notifier_add_subdev(notifier, asd);
> +	ret = __v4l2_async_notifier_add_subdev(notifier, asd);
>  	if (ret) {
>  		kfree(asd);
>  		return ERR_PTR(ret);
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 5353e37eb950..919fde20032e 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -833,7 +833,7 @@ v4l2_async_notifier_fwnode_parse_endpoint(struct device *dev,
>  	if (ret < 0)
>  		goto out_err;
>  
> -	ret = v4l2_async_notifier_add_subdev(notifier, asd);
> +	ret = __v4l2_async_notifier_add_subdev(notifier, asd);
>  	if (ret < 0) {
>  		/* not an error if asd already exists */
>  		if (ret == -EEXIST)
> diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> index 25c9ebd3f963..ef4ac3559be9 100644
> --- a/include/media/v4l2-async.h
> +++ b/include/media/v4l2-async.h
> @@ -138,17 +138,22 @@ void v4l2_async_debug_init(struct dentry *debugfs_dir);
>  void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier);
>  
>  /**
> - * v4l2_async_notifier_add_subdev - Add an async subdev to the
> + * __v4l2_async_notifier_add_subdev - Add an async subdev to the
>   *				notifier's master asd list.
>   *
>   * @notifier: pointer to &struct v4l2_async_notifier
>   * @asd: pointer to &struct v4l2_async_subdev
>   *
> + * \warning: Drivers should avoid using this function and instead use one of:
> + * @v4l2_async_notifier_add_fwnode_subdev,
> + * @v4l2_async_notifier_add_fwnode_remote_subdev or
> + * @v4l2_async_notifier_add_i2c_subdev.
> + *
>   * Call this function before registering a notifier to link the provided @asd to
>   * the notifiers master @asd_list. The @asd must be allocated with k*alloc() as
>   * it will be freed by the framework when the notifier is destroyed.
>   */
> -int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
> +int __v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
>  				   struct v4l2_async_subdev *asd);
>  
>  /**
>